Co-reporter:Xin Lu;Yan Liu;Wenfei Zhang;Xueying Zhang
Journal of Coatings Technology and Research 2017 Volume 14( Issue 4) pp:937-944
Publication Date(Web):19 April 2017
DOI:10.1007/s11998-016-9902-5
Bisphenol A/diaminodiphenylmethane (BA-ddm)-based polybenzoxazine precursor was synthesized from 4,4′-diaminodiphenylmethane, bisphenol A, and paraformaldehyde. The curing behavior of BA-ddm was studied by using differential scanning calorimeter and Fourier transform infrared spectrometer techniques. To verify the anticorrosion property, cured polybenzoxazine (PBA-ddm) coatings were prepared on mild steel (MS) through dip-coating and thermal curing methods. The surface properties of cured PBA-ddm coatings were characterized by microscopy and contact angle measurement. The electrochemical measurements were carried out to investigate the corrosion properties of PBA-ddm-coated MS. The results showed that PBA-ddm-coated MS samples exhibited high anticorrosive performance with the corrosion current reduced by two orders of magnitude than that of pristine MS.
Co-reporter:Zhicheng Bian, Zhong XinXin Meng, Miao Tao, YuHao Lv, Jia Gu
Industrial & Engineering Chemistry Research 2017 Volume 56(Issue 9) pp:
Publication Date(Web):February 15, 2017
DOI:10.1021/acs.iecr.6b04027
Several Ni-based SBA-16 catalysts were synthesized by a citric acid (CA)-assisted impregnation method and applied for syngas methanation in a fix-bed reactor. Various characterization techniques (N2 physical adsorption, powder X-ray diffraction, temperature-programmed reduction, temperature-programmed desorption, X-ray photoelectron spectroscopy, transmission electron microscopy, scanning electron microscopy, and ultraviolet–visible spectroscopy) were used to characterize the catalysts. The amount of citric acid has significant influence on the properties of the catalysts. A small amount of CA could improve the dispersion of nickel species and refine the particle size of the catalysts. The refined nickel particles (3–5 nm) could anchor into the pores (6–7 nm) of the silica, which leads to the confinement of nickel particles. The best activity was obtained on Ni/SBA-16–15%CA catalysts with 100% CO conversion and 99.9% CH4 selectivity at 350 °C, 0.1 MPa, and 15 000 mL/g/h. The catalysts prepared with CA exhibited excellent stability after being calcined at high temperature, which could be attributed to the refined nickel particles anchored into the pores of the silica.
Co-reporter:Yuhao Lv, Zhong Xin, Xin Meng, Miao Tao, Zhicheng Bian, Jia Gu, Wenli Gao
Applied Catalysis A: General 2017 Volume 543(Volume 543) pp:
Publication Date(Web):5 August 2017
DOI:10.1016/j.apcata.2017.05.038
•Ni species are highly dispersed as clusters into the mesopores of KIT-6.•A suitable interaction between Ni and KIT-6 is obtained over 0.5MoNi/KIT-6.•High pressure will accelerates the aggregation of Ni particles.Ni catalysts supported on mesoporous silica KIT-6 with and without promoters (La, Mg and Mo) were prepared by co-impregnation and their catalytic performances on CO methanation were conducted in fixed-bed reactor. As a result, promoters had a negligible benefit to the dispersion of Ni particles since Ni species were highly dispersed on KIT-6. While the metal Ni surface area was reduced due to partial coverage of metal Ni by promoters. Besides the improvement of the promoters (La and Mo) on CO methanation activity, a suitable Ni- support interaction can hindrance the aggregation of Ni particles on 0.5MoNi/KIT-6 during thermal treatment. While the aggregation of Ni particles was severe on Ni/KIT-6 and 0.3LaNi/KIT-6 due to the weak interaction between Ni and support. Furthermore, Mg enhanced the interaction between Ni and KIT-6 by forming NiO-MgO solid solution, but simultaneously some “unsupported” free and “surface rich” Ni species was formed, which would aggregate into larger particles (ca. 25 × 40 nm) during thermal treatment. It was worth mentioning that high pressure (3 MPa) improved the catalytic activities and thermostability of catalysts for CO methanation but the aggregation of metal particles were more severe after thermal treatment in reactants under high temperature.Download high-res image (163KB)Download full-size image
Co-reporter:Shicheng Zhao, Kehua Liu, Shuai Zhou, Yaoqi Shi, Zhong Xin
Polymer 2017 Volume 132(Volume 132) pp:
Publication Date(Web):6 December 2017
DOI:10.1016/j.polymer.2017.10.024
•A novel self-dispersed β nucleating agent (β-NA) for iPP was found.•The β-NA displayed the unique nucleation behavior and mechanism during the crystallization of iPP.•The β-NA was converted into ZnO nanoparticles and the group of ROO¯ chemically absorbed on the surface of ZnO nanoparticles.•The problems of agglomeration of ZnO nanoparticles in iPP was well solved by in situ thermal decomposition of the β-NA.Adding β nucleating agent (β-NA) is the most effective way to induce β-form in isotactic polypropylene (iPP). However, the problem of agglomeration and poor dispersion result in the low nucleation efficiency of β-NA. We reported herein a novel self-dispersed β nucleating agent of iPP, zinc salt of bicycle [2.2.1] hept-5-ene-2-dodecanamide-3-carboxylate (NBDA30), which exhibited a unique nucleation behavior during the crystallization of iPP. The results showed that the content of β crystal of iPP nucleated with 0.2 wt% NBDA30 can reach 0.82 (kβ value), implying that NBDA30 is an effective β nucleating agent of iPP. Polarized optical microscopy (POM) analyses showed that the NBDA30 gradually melted upon increasing temperature and then the melt induced the crystallization of iPP. The unique nucleation behavior was first reported in this study and the nucleation mechanism of iPP induced by NBDA30 was revealed by POM, fourier transform infrared spectroscopy (FTIR), wide-angle X-ray diffraction (WAXD), transmission electron microscopy (TEM) and scanning electron Microscope (SEM). The results indicated that the NBDA30 was converted into ZnO nanoparticles and the group of ROO¯ chemically adsorbed on the surface of ZnO nanoparticles (NPs). The problem of agglomeration of ZnO nanoparticles was well solved by in situ thermal decomposition of NBDA30 and the compatibility of ZnO and iPP matrix was greatly improved by chemical adsorption of organic carboxylic acid on the surface of ZnO NPs. Therefore, the nucleation efficiency of ZnO NPs was greatly increased. The preparation method of self-dispersed nucleating agent can potentially be extended to other nucleating agent or additives to prevent them from aggregating.Download high-res image (477KB)Download full-size image
Co-reporter:Miao Tao, Zhong Xin, Xin Meng, Zhicheng Bian, Yuhao Lv
Fuel 2017 Volume 188() pp:267-276
Publication Date(Web):15 January 2017
DOI:10.1016/j.fuel.2016.09.081
•Methanation catalyst is first prepared by surfactant-assisted impregnation method.•The surfactant can hinder the migration of metal ions during drying.•The surfactant can inhibit the aggregation of NiO during calcination.•The 10%Ni/S15(3) catalyst showed excellent catalytic activity and stability.In this work, several nickel-based SBA-15 catalysts were prepared by surfactant-assisted impregnation method and applied in CO methanation reaction. The characterization results showed that Ni species were uniformly distributed in the ordered mesoporous channels of SBA-15 by adding proper surfactants. The morphologies of the unroasted catalysts and spent catalysts after 100 h stability test were also investigated. The surfactant can hinder the migration of metal ions during drying and inhibit the aggregation of NiO during calcination, which ultimately improve the nickel dispersion. Consequently, the Ni/SBA-15 catalysts prepared with surfactant-assisted impregnation method exhibited superior activity and excellent thermostability owing to the moderate interaction between nickel and support, high nickel surface area and the confinement of support. The 10%Ni/S15(3) catalyst achieved the best activity with 100% CO conversion and about 99.9% CH4 yield at 350 °C, 0.3 MPa and 15,000 mL/g/h.Figure optionsDownload full-size imageDownload as PowerPoint slide
Co-reporter:Jiahui Gu;Xin Meng;Shuzhen Sun;Qingan Qiao;Hongbo Deng
Journal of Chemical Technology and Biotechnology 2016 Volume 91( Issue 5) pp:1327-1338
Publication Date(Web):
DOI:10.1002/jctb.4726
Abstract
BACKGROUND
Recovering high value-added substances (oil, zein and carotenoids) from corn distillers dried grains with solubles (DDGS), the major coproduct of bioethanol, is important to enhance the profit of the corn ethanol process. Currently, few studies have been reported on separating high value-added substances in a process suitable for industrialization. In this article, a semi-continuous countercurrent extraction method was investigated to refine the corn DDGS.
RESULTS
First, an oil yield as high as 94.5% (based on oil content in DDGS) was measured using a series of five packed columns. Second, the DDGS residues after oil extraction were used for zein extraction, obtaining a zein yield of 24.5% (based on protein content in DDGS) with a series of four packed columns. Moreover, the carotenoids in zein were extracted by anhydrous ethanol in a Soxhlet apparatus. The extractives, which accounted for 17% of the original mass of zein, had a carotenoids content of 2.4 mg g−1. Finally, zein was decolored by hydrogen peroxide to form a whiter product.
CONCLUSIONS
The semi-continuous countercurrent method was developed successfully to refine the corn DDGS. The corn oil with high acid value was a perfect feedstock for biodiesel. The zein obtained achieved the quality of a commercial product. © 2015 Society of Chemical Industry
Co-reporter:Xin Meng, Guotao Shi, Chushi Wu, Weijie Chen, Zhong Xin, Yaoqi Shi, Yan Sheng
Polymer Degradation and Stability 2016 Volume 124() pp:112-118
Publication Date(Web):February 2016
DOI:10.1016/j.polymdegradstab.2015.12.003
PLA, which is synthesized from natural resource, has good mechanical property and biodegradable ability, so it is well recognized as a reasonable substituent of petroleum base plastic. Triphenyl Phosphite can increase the molecular weight of PLA through the chain extension with PLA in the melt processing. In this paper, the factors that influence the chain extension of TPP in PLA were studied in detail. The results show that the adding amount of TPP, processing temperature and processing time affect the chain extension of TPP in PLA. When the adding amount of TPP is about 2wt% compared to PLA, the melt temperature is 180 °C and the melt time lasts 15 min, the chain extension is the best. On the conditions, the molecular weight of PLA increases about 56% compared to virgin PLA and can reach 2.52 × 105 g/mol. Furthermore, the chain extension makes the activation energy of oxidation degradation of PLA increases by 14.3%, so the chain extended PLA named PLA-TPP indicates the better oxidation stability.
Co-reporter:Miao Tao, Zhong Xin, Xin Meng, Yuhao Lv and Zhicheng Bian
RSC Advances 2016 vol. 6(Issue 42) pp:35875-35883
Publication Date(Web):12 Apr 2016
DOI:10.1039/C6RA04490E
Several nickel-based SBA-15 catalysts with Ni content in range of 3 wt% to 10 wt% were prepared by the “double-solvent” impregnation method and investigated for synthetic natural gas (SNG) production in a continuous flow fixed-bed reactor. Using a double-solvent impregnation method could improve the dispersion of nickel particles, which significantly improved the catalytic activity of the Ni-based catalysts in the syngas methanation reaction. The 10%Ni/SBA-15(D) catalyst achieved the best activity with 100% CO conversion and about 99% CH4 yield at 400 °C, 0.3 MPa and 15000 mL g−1 h−1. The catalysts were characterized by N2 adsorption–desorption, X-ray diffraction (XRD), transmission electron microscope (TEM), H2-temperature-programmed reduction (H2-TPR), H2 pulse chemisorption, CO-temperature-programmed desorption (CO-TPD) and thermogravimetric (TG). It could be speculated that using the double-solvent impregnation method strengthened the interactions between NiO and the support based on the TPR results. The results of XRD and TG analysis showed that catalyst sintering rather than carbon deposition led to catalyst deactivation in the heat-resistant performance and 100 h stability test.
Co-reporter:Xin Lu, Yan Liu, Changlu Zhou, Wenfei Zhang and Zhong Xin
RSC Advances 2016 vol. 6(Issue 7) pp:5805-5811
Publication Date(Web):12 Jan 2016
DOI:10.1039/C5RA22980D
Hydrophobic bisphenol A-based polybenzoxazine (PBA-a) coatings were prepared on mild steel (MS) through a simple dip coating and thermal curing method. The thermal curing process of PBA-a coating was studied by Fourier transform infrared spectrometer (FTIR) and differential scanning calorimeter (DSC). The film-forming property and the wettability of PBA-a coatings were characterized by the microscopy and the contact angle measurement, respectively. The effects of benzoxazine monomer concentration and curing temperature on corrosion resistance of PBA-a coatings on MS were investigated by the electrochemical measurements. The results revealed that the corrosion resistance properties of PBA-a coatings improved with the increasing concentration of BA-a monomer. For the samples with the BA-a concentration of 500 g L−1, the protection efficiency values of PBA-a coatings were more than 99.0% when the curing temperature increased from 150 °C to 210 °C.
Co-reporter:Changlu Zhou, Jiaping Lin, Xin Lu and Zhong Xin
RSC Advances 2016 vol. 6(Issue 34) pp:28428-28434
Publication Date(Web):01 Mar 2016
DOI:10.1039/C6RA02215D
Polybenzoxazine/epoxy composite coating has been developed on mild steel (MS) substrates by a thermal curing method. The reaction between two components was characterized by Fourier transform infrared spectroscopy (FTIR). The effects of incorporating epoxy on the corrosion resistance of coated steel were investigated by open circuit potential, potentiodynamic polarization, and electrochemical impedance spectroscopy, respectively. The resulted composite coated samples exhibit significant enhancement on the corrosion resistance of MS with the corrosion current reduced by more than one order of magnitude, and the enhancement is improved with an increase in the epoxy content, which benefits from the dual crosslinking network of the composite coating through the incorporation of epoxy. In addition to enhancing the coating barrier performance, all coated samples are substantially hydrophobic with a contact angle of above 100° before and even after the polarization measurements.
Co-reporter:Shicheng Zhao;Hanzhang Gong;Xin Yu;Shibao Sun;Shuai Zhou ;Yaoqi Shi
Journal of Applied Polymer Science 2016 Volume 133( Issue 32) pp:
Publication Date(Web):
DOI:10.1002/app.43767
ABSTRACT
Zinc adipate (Adi-Zn) was observed to be a highly active and selective β-nucleating agent for isotactic polypropylene (iPP). The effects of Adi-Zn on the mechanical properties and the β-crystals content of nucleated iPP were investigated. The impact strength of iPP nucleated with 0.2 wt % Adi-Zn was 1.8 times higher than that of neat iPP. In addition, wide-angle X-ray diffraction analysis indicated that the content of β-crystals in nucleated iPP (kβ value) reached 0.973 with 0.1 wt % Adi-Zn, indicating that Adi-Zn is a highly active and selective β-nucleating agent for iPP. Furthermore, fast scanning chip calorimetry (FSC) studies using cooling rates from 60 to 13,800 °C min−1 revealed that the formation of β-crystals significantly depended on the cooling rates. At cooling rates below 3000 °C min−1, only β-crystals existed. However, at cooling rates above 6000 °C min−1, β-crystals failed to form. Moreover, a lower critical crystallization temperature that corresponded to the generation of β-crystals was investigated using cooling-induced crystallization, and the results are in good agreement with those of a previous study. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43767.
Co-reporter:Juan Liu;Xin Lu 辛忠;Chang-lu Zhou
Chinese Journal of Polymer Science 2016 Volume 34( Issue 8) pp:919-932
Publication Date(Web):2016 August
DOI:10.1007/s10118-016-1810-8
A series of mono-functional benzoxazine monomers with different N-substituents were synthesized from phenol, formaldehyde, and various amines (ammonia, methylamine, n-butylamine, dodecylamine), named P-am, P-m, P-b, and P-da, respectively. The surface properties of these polybenzoxazine films were proven by contact angle measurements. The hydrogen bond network of the polybenzoxazine systems was studied using the FTIR spectra. And the results showed that the surface free energy increased with increasing the fraction of intermolecular hydrogen bonding when the N-substituent was an alkyl chain. However, the rule was not suitable when the N-substituent was H. That was because there was one more kind of intramolecular hydrogen bond in the poly(P-am). Based on these findings, we proposed that both the N-substituent alkyl group and the fraction of intermolecular hydrogen bonding had effects on the surface free energy.
Co-reporter:Shuai Zhou;Weixia Wang;Shicheng Zhao
Journal of Materials Science 2016 Volume 51( Issue 12) pp:5598-5608
Publication Date(Web):2016 June
DOI:10.1007/s10853-016-9856-0
The crystallization behaviors and mechanical properties of both linear isotactic polypropylene (iPP) and long chain branching polypropylene (LCBPP) were investigated with differential scanning calorimetry, polarized optical microscopy, and wide-angle X-ray diffraction. The results indicated that the long chain branching (LCB) structure could act as nucleating agent accelerating the nucleation but impeding the crystal growth of LCBPP, and eventually increased the crystallization peak temperature and decreased the spherulite size of LCBPP. Moreover, with the presence of LCB structure, β-form polypropylene was generated in LCBPPs under injection molding conditions, and the content of β-form increased with the increasing of LCB structure content. Benefiting from the combined effect of the LCB structure and β-form crystal, the LCBPPs revealed not only outstanding toughness but also desired stiffness. The impact strength, flexural modulus and tensile strength of HMSPP3 were increased by, respectively, 260.0, 54.7, and 17.2 % than those of linear iPP. These results are helpful to develop new types of high performance polypropylene.
Co-reporter:Yaoqi Shi;Dongkang Hu;Shicheng Zhao
Journal of Materials Science 2016 Volume 51( Issue 10) pp:4880-4887
Publication Date(Web):2016 May
DOI:10.1007/s10853-016-9793-y
Chain conformation order of poly (l-lactic acid) (PLLA) was investigated by time-lapsed Fourier transform infrared (FTIR) spectroscopy and two-dimensional infrared correlation spectroscopy during the isothermal crystallization at 140 °C. The result showed that the PLLA formed α-crystal during the isothermal crystallization at 140 °C. According to the detailed information in the region of 1000–1500 cm−1 investigated by infrared and 2D correlation spectroscopy, it was found that the conformation of C–O–C groups changed prior to that of CH3 groups. Moreover, the formation of the initial helix chain conformation was interfered by the interchain interactions between the CH3 groups, which consequently resulted in the formation of α-crystal with the distorted 103 helix conformation.
Co-reporter:Weixia Wang;Shuai Zhou;Yaoqi Shi
Journal of Materials Science 2016 Volume 51( Issue 2) pp:788-796
Publication Date(Web):2016 January
DOI:10.1007/s10853-015-9402-5
A strategy to prepare foamable isotactic polypropylene (iPP) was proposed by introducing crystal nucleating agent, 1,3:2,4-bis(p-methylbenzylidene) sorbitol (S20), and the foaming mechanism was also investigated. When a proper concentration (above 0.3 wt%) of S20 was added, iPP/S20 exhibited excellent foaming performance, yielding uniform cells with well-defined structures and higher cell density than those of neat iPP. The results of rheological analysis and TEM confirmed the formation of S20 nanofibrils in iPP matrix. The existence of these nanofibrils increased the melt viscosity of iPP and enhanced the bubble nucleation in the foaming process, and thus should be responsible for the improved foaming ability of iPP. Moreover, iPP/S20 could be foamed in a remarkably wide temperature range from 143 to 163 °C. In comparison, another crystal nucleating agent, sodium 2,2′-methylene-bis-(4,6-di-tert-butylphenyl)-phosphate (NA40), contributed little to the foamability of iPP although it also induced the crystallization of iPP.
Co-reporter:Changlu Zhou;Xin Lu
Journal of Coatings Technology and Research 2016 Volume 13( Issue 1) pp:63-72
Publication Date(Web):2016 January
DOI:10.1007/s11998-015-9722-z
Organoclays modified by two different pillaring agents were introduced in polybenzoxazine (PBz) coatings on mild steel (MS). Both physicochemical properties and corrosion protection performance of composite coatings were fully investigated with the assistance of FTIR, XRD, AFM, SEM, and electrochemical measurements. The octadecyl quaternary ammonium-modified organoclays exhibited an exfoliated structure in polymer matrix, which benefited little in coatings’ barrier property. However, organoclays modified by dimethyl dioctadecyl quarternary ammonium induced an intercalated structure in composites, which greatly enhanced the corrosion resistance of poly(BA-aptms) with corrosion rate reduced by 3 and 4 orders of magnitude, respectively, compared to PBz and bare MS when 3 wt% of organoclays were added.
Co-reporter:Weixia Wang;Shuai Zhou
Frontiers of Chemical Science and Engineering 2016 Volume 10( Issue 3) pp:396-404
Publication Date(Web):2016 September
DOI:10.1007/s11705-016-1577-z
Foamable high melt strength polypropylene (HMSPP) was prepared by grafting styrene (St) onto polypropylene (PP) and simultaneously introducing polydimethylsiloxane (PDMS) through a one-step melt extrusion process. The effect of PDMS viscosity on the foaming behavior of HMSPP was systematically investigated using supercritical CO2 as the foaming agent. The results show that the addition of PDMS has little effect on the grafting reaction of St and HMSPP exhibits enhanced elastic response and obvious strain hardening effect. Though the CO2 solubility of HMSPP with PDMS (PDMS-HMSPP) is lower than that of HMSPP without PDMS, especially for PDMS with low viscosity, the PDMS-HMSPP foams exhibit narrow cell size distribution and high cell density. The fracture morphology of PDMS-HMSPP shows that PDMS with low viscosity disperses more easily and uniformly in HMSPP matrix, leading to form small domains during the extrusion process. These small domains act as bubble nucleation sites and thus may be responsible for the improved foaming performance of HMSPP.
Co-reporter:Zhicheng Bian, Xin Meng, Miao Tao, YuHao Lv, Zhong Xin
Journal of Molecular Catalysis A: Chemical 2016 Volume 417() pp:184-191
Publication Date(Web):June 2016
DOI:10.1016/j.molcata.2016.03.028
•Amino-functionalized mesoporous material SBA-16 was prepared by silylation.•Uniform size of nickel particles were observed on the modified material.•Better thermalstability and long-term stability were achieved for Ni/SBA-16-NH2 catalyst.Via modification of mesoporous material SBA-16 with silane coupling agent, a new functionalized SBA-16 catalyst immobilized Ni has been prepared. The performance of the catalyst for CO methanation then were systemically investigated in a continuous flow fixed-bed reactor. The as-synthesized catalyst was characterized with N2 absorption-desorption, X-ray diffraction, Transmission electron microscopy (TEM), FT-IR spectrum, 29Si-nuclear magnetic resonance (NMR), H2—Temperature Programmed Reduction (TPR) and H2 pulse chemisorption. After modification by aminopropyl-trimethoxysilane (APTMS), the internal surface silanol group of support SBA-16 was replaced by amino-groups. The replacement of hydroxyl groups by amino groups could prevent the agglomeration of metal ion in the solution. Also uniform nickel particle size was observed because the replaced organic groups on SBA-16 could form homogeneous interaction towards the metal. Comparing with the catalyst without functionalized, the catalyst Ni/SBA-16-NH2 exhibited higher activity, excellent heat-resistant performance and better stability in CO methanation. The CO conversion and CH4 selectivity could be 100% and 99.9% at the optimal temperature. Meanwhile, the catalyst showed no decrease of activity in the 100 h life test.
Co-reporter:Xin Lu;Yuhui Hou;Congyi Ye;Jie Zha
Journal of Sol-Gel Science and Technology 2016 Volume 77( Issue 1) pp:145-151
Publication Date(Web):2016 January
DOI:10.1007/s10971-015-3838-6
Uniform rhodamine B-doped poly(3-glycidoxypropylsilsesquioxane) (RB-PGPSQ) fluorescent microspheres with epoxy functional groups were prepared using 3-glycidoxypropyltrimethoxysilane (GPTMS) as precursor via a two-step acid–base-catalyzed sol–gel method. The hydrolysis and condensation processes of GPTMS were tracked by 29Si magnetic resonance spectrometer and field emission scanning electron microscopy to reveal the formation process of the fluorescent microspheres. The average diameters of the fluorescent microspheres could be tuned from 2.07 to 5.33 μm by adjusting the concentrations of GPTMS precursor. The results of confocal microscopy and fluorescence spectrophotometer showed that RB-PGPSQ fluorescent microspheres possessed good fluorescent properties and high photostability.
Co-reporter:Miao Tao, Xin Meng, Yuhao Lv, Zhicheng Bian, Zhong Xin
Fuel 2016 Volume 165() pp:289-297
Publication Date(Web):1 February 2016
DOI:10.1016/j.fuel.2015.10.023
•The Ni/SBA-15 catalyst is first applied in the CO methanation reaction.•The effect of impregnation solvents could be related to the polarities of solvents.•The nickel dispersion depended on the solubility of nickel nitrate.•The 20%Ni/SBA-15(ET) catalyst showed excellent catalytic activity and stability.A series of SBA-15-supported Ni catalysts were prepared by incipient-wetness impregnation with different nickel nitrate solutions and applied in the CO methanation reaction for the production of synthetic natural gas (SNG). The catalysts were also characterized using X-ray diffraction (XRD), N2 physisorption measurements, hydrogen temperature-programmed reduction (H2-TPR), CO chemisorption, CO temperature-programmed desorption (CO-TPD) and transmission electron microscope (TEM). The results showed that the impregnation solvent influenced the catalytic activity in the CO methanation. The catalyst 20%Ni/SBA-15(ET) prepared from ethanol solution exhibited the highest activity with 100% CO conversion and 95% CH4 yield at 300 °C under 0.3 MPa. The effect of impregnation solvents could be related to the polarities of solvents and the solubility of nickel nitrate. The decreased polarity of the solvent caused an increase in the interaction between the nickel complex and silica surface, which would promote the fixation of the precursor onto the silica support and increase the nickel dispersion. As a result, the activity of the catalysts was improved effectively. The lifetime test also indicated that Ni based SBA-15 catalysts had a good catalytic stability. This was because of the stronger interaction between Ni and support.
Co-reporter:Shuai Zhou;Weixia Wang;Shicheng Zhao;Yaoqi Shi
Polymer Engineering & Science 2016 Volume 56( Issue 2) pp:240-247
Publication Date(Web):
DOI:10.1002/pen.24252
Long chain branching polypropylene (LCBPP) with different long chain branching (LCB) contents were prepared by reactive extrusion in the presence of styrene and benzoyl peroxide, and their shear-induced crystallization behaviors were investigated. The results indicated that the LCB structure extended the relaxation time of LCBPP in the molten state, which led to the formation of β-form polypropylene under shear and high cooling rate. The content of β-form (Kβ) increased with the increase of LCB content, shearing rate and cooling rate. The Kβ value of LCBPP3 whose weight average molecular weight was 920,000 g mol−1 could be up to 52.0% with a shear rate of 60 s−1 associated with a cooling rate of 280°C min−1. This study is expected not only to have a deeper understanding of the shear-induced crystallization behavior of LCBPP, but also provide a new strategy to obtain high level β-form polypropylene. POLYM. ENG. SCI., 56:240–247, 2016. © 2015 Society of Plastics Engineers
Co-reporter:Zhicheng Bian, Xin Meng, Miao Tao, YuHao Lv, Zhong Xin
Fuel 2016 Volume 179() pp:193-201
Publication Date(Web):1 September 2016
DOI:10.1016/j.fuel.2016.03.091
•SBA-16 is first used as support of catalysts for CO methanation reaction.•The activity of catalysts was correlated with the metallic surface area of nickel.•Mo–Ni/SBA-16 obtained the best activity (100% CO conversion and 97% CH4 selectivity).A series of Ni/SBA-16 and NiMo/SBA-16 catalysts were prepared by the impregnation methods and their performance on synthetic natural gas (SNG) production were systematically investigated in a continuous flow fixed-bed reactor. Catalysts were characterized by nitrogen physisorption, powder X-ray diffraction (XRD), transmission electron microscopy (TEM), H2 pulse chemisorption, temperature-programmed reduction (TPR), X-ray photoelectron spectroscopy (XPS). Catalysts with the addition of MoO3 exhibited larger metal surface area and better heat-resistant performance, because the strong interaction between Ni and SBA-16 was formed. Mo–Ni/SBA-16(1 wt%) achieves the best activity with 100% CO conversion and 97% CH4 selectivity at 350 °C, 0.1 MPa, and 15,000 mL/g/h. The activity of Mo–Ni/SBA-16(1 wt%) remain stable after calcination in reactant gases at 700 °C and during the 100 h reaction period. It was noting that for catalysts with large metal particle size (more than 20 nm) CO methanation turned to be a structure-insensitive reaction, which the activity is related to the amount of active site rather than the particle size.
Co-reporter:Wenfei Zhang, Xin Lu, Zhong Xin and Changlu Zhou
Nanoscale 2015 vol. 7(Issue 46) pp:19476-19483
Publication Date(Web):26 Oct 2015
DOI:10.1039/C5NR06425B
Two important properties—the low surface free energy of polybenzoxazine (PBZ) and the photocatalysis-induced self-cleaning property of titanium dioxide (TiO2) nanoparticles—are combined to develop a promising approach for oil/water separation. They are integrated into a multifunctional superhydrophobic and superoleophilic material, PBZ/TiO2 modified polyester non-woven fabrics (PBZT), through a simple dip coating and subsequent thermal curing method. The resulting PBZT reveals excellent mechanical durability and strong resistance to ultraviolet (UV) irradiation as well as acid and alkali. This durable superhydrophobic and superoleophilic fabric is efficient for separating oil/water mixtures by gravity with high separation efficiency, and it can also purify wastewater that contains soluble dyes, which makes it more effective and promising in treating water pollution. Importantly, PBZT demonstrates an integrated self-cleaning performance on the removal of both oil and particle contamination. It is expected that this simple process can be readily adopted for the design of multifunctional PBZ/TiO2 based materials for oil/water separation.
Co-reporter:Wenfei Zhang, Xin Lu, Zhong Xin, Changlu Zhou and Juan Liu
RSC Advances 2015 vol. 5(Issue 68) pp:55513-55519
Publication Date(Web):10 Jun 2015
DOI:10.1039/C5RA06410D
Two important properties are combined: the low surface free energy property of polybenzoxazine (PBZ) and the photo-induced superhydrophilicity property of TiO2. A benzoxazine monomer, synthesized by a one-step method, is incorporated with TiO2. Polybenzoxazine/titanium dioxide (PBZ/TiO2) nanocomposite films are prepared using spin coating and a thermal curing method. As a result, a superhydrophobic PBZ/TiO2 film with the largest water contact angle (CA) of ∼166 ± 1° is developed by incorporating a low content of TiO2 (11 wt%, relative to the weight of the benzoxazine monomer) into a PBZ system without any fluorine-containing surface modification agents. The as-prepared superhydrophobic film has good adhesion to glass substrates, and its superhydrophobicity is stable even after heat treatment at 300 °C for 1 h and environmentally durable for more than half a year. When the content of TiO2 is increased to 60%, the consequent nanocomposite film exhibits hydrophobicity–superhydrophilicity transitions with a variation of around 125° in water CA upon ultraviolet (UV) exposure–heat treatment cycles. The effects of the content of TiO2 on the surface wettability, morphology and reversibly switchable wettability of the PBZ/TiO2 films are investigated in detail.
Co-reporter:Shicheng Zhao, Xin Yu, Hanzhang Gong, Zhong Xin, Yaoqi Shi, and Shuai Zhou
Industrial & Engineering Chemistry Research 2015 Volume 54(Issue 31) pp:7650-7657
Publication Date(Web):July 28, 2015
DOI:10.1021/acs.iecr.5b02003
The addition of foreign substances is well-known to be able to improve the crystallization of isotactic polypropylene (iPP) following a nucleation-promoting mechanism. In the present work, however, we found that zinc salt of 1, 4, 5, 6, 7, 7-hexachlorobicyclo [2.2.1] hept-5-ene-2, 3-dicarboxylic acid (HCHD-Zn) unexpectedly decreased the crystallization temperature (Tcp) and crystallization rate of iPP, generating remarkable antinucleation effects. The results of differential scanning calorimetry (DSC) and polarized optical microscopy (POM) showed Tcp of iPP decreased more than 4 °C and nucleation densities of iPP decreased nearly 70% upon the addition of the “anti-nucleating agent” HCHD-Zn. Isothermal crystallization kinetics indicated HCHD-Zn lowered the crystallization kinetic constant k of iPP but had similar Avrami exponent with neat iPP, which revealed HCHD-Zn hindered the crystallization of iPP but did not change the type of nucleation and growth geometries of iPP. We proposed a mechanism of antinucleation of iPP upon the addition of HCHD-Zn from a structural perspective. Hydrogens on the tertiary carbons in the melt of iPP may react with the chlorine in the HCHD-Zn particles dispersed within. The removal of hydrochloride left a 3D network of iPP chains cross-linked by HCHD-Zn particles. Therefore, the restricted movement of polymer chains inhibited the nucleation of iPP.
Co-reporter:Ting Han;Yaoqi Shi;Shicheng Zhao;Xin Meng;Hui Xu ;Shuai Zhou
Journal of Applied Polymer Science 2015 Volume 132( Issue 20) pp:
Publication Date(Web):
DOI:10.1002/app.41977
ABSTRACT
Two functional polysilsesquioxane microspheres, poly(epoxypropoxy)silsesquioxane (PESQ) and poly(epoxypropoxy/amino)silsesquioxane (PEASQ), were grafted onto commercial polylactic acid (PLA) via functional group reactions through melt processing and directly used as novel chain extenders to improve the thermal stability of PLA. During the whole reaction time of 35 min, the torques of P-2PESQ and P-1PEASQ were 60% higher than that of processed PLA. Thermal gravimetric analysis (TGA) revealed that the addition of PESQ or PEASQ into PLA increased the onset temperature for thermal degradation. PEASQ was found to be a potential chain extender for PLA. Compared with the processed PLA, the thermal decomposition temperatures of PEASQ modified PLA increased from 318 to 334°C at 5% weight loss. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41977.
Co-reporter:Shuai Zhou;Shicheng Zhao
Polymer Engineering & Science 2015 Volume 55( Issue 2) pp:251-259
Publication Date(Web):
DOI:10.1002/pen.23889
A novel strategy was developed by melt grafting reaction in the presence of macromonomer vinyl polydimethylsiloxane (VS) and comonomer styrene (St) for preparing high melt strength polypropylene (HMSPP), and the rheological behavior, melt strength, and foaming ability of HMSPP were investigated. The results showed that VS and St were successfully grafted onto isotactic polypropylene (iPP), and the melt strength of HMSPP increased by more than 12 times compared to that of the virgin iPP. Moreover, HMSPP exhibited excellent foaming ability with smaller cell size, higher cell density, and higher expansion ratio compared to the virgin iPP when supercritical carbon dioxide was used as the blowing agent. POLYM. ENG. SCI., 55:251–259, 2015. © 2014 Society of Plastics Engineers
Co-reporter:Jie Zha;Xin Lu
Journal of Sol-Gel Science and Technology 2015 Volume 74( Issue 3) pp:677-684
Publication Date(Web):2015 June
DOI:10.1007/s10971-015-3648-x
For the purpose to realize broadband antireflection on glass substrates, double layer mesoporous polysiloxane coatings were well designed by solving Maxwell equation and prepared through sol–gel dip-coating method using tri-block copolymer (EO20PO70EO20) as porogen. The obtained double layer coatings revealed broadband antireflective performance within wavelength range from 400 to 900 nm with a maximum transmittance of 99.2 % around 520 nm, which was in well agreement with the calculated results. The mesopore structure was confirmed by AFM and N2 adsorption–desorption measurement. Moreover, it was found that the outer layer of resultant coatings showed increased hydrophobicity along with increased temperature. Hence, we proposed that the condensation degree of silica network played an important role on the surface wettability of polysiloxane coatings, which was fully investigated with the assistance of FT-IR and water contact angle measurements.
Co-reporter:Jiahui Gu, Zhong Xin, Xin Meng, Shuzhen Sun, Qingan Qiao, Hongbo Deng
Fuel 2015 Volume 146() pp:33-40
Publication Date(Web):15 April 2015
DOI:10.1016/j.fuel.2014.12.080
•Transestertification of DMC and oil with high acid value and high water content.•The reaction route and reaction mechanism of the DMC and FFA were speculated.•Evaluating of different water absorbents on the yield of biodiesel.•Novozym 435/SAP showed great catalytic activity and operational stability.•Novozym 435/SAP is easy to be recycled and can be used in fixed bed reactor.The corn oil extracted from distillers dried grains with solubles (DDGS), which has a high acid value of 41.6 mg KOH/g and a high water content of 4.5%, is used to produce biodiesel in this article. The transesterification of dimethyl carbonate (DMC) and DDGS-extracted corn oil was studied at the catalysis of Novozym 435. Meanwhile, several water removal agents, which include acrylic super absorbent resin (SAP), 4A-molecular sieve, blue silica-gel and tert-butanol, were added to absorb the water during the reaction. The yield of fatty acid methyl esters (FAMEs) was analyzed by GC with internal standard method. The effect of different reaction conditions (type of water absorbent, molar ratio of DMC to oil, reaction time and temperature, lipase and SAP amount) on the yield of FAMEs were also discussed. Then the highest yield of FAMEs could reach 91.0% at 60 °C for 18 h with molar ratio of DMC to oil 15:1, Novozym 435 amount of 20 wt% and SAP amount of 10 wt% (based on the oil mass). Finally, Novozym 435/SAP showed excellent operational stability without losing any catalytic activity after 8 cycles of repeated use, and the water absorbed by Novozym 435/SAP can be dried at mild temperature (60 °C). Because it is easy to be recycled, the Novozym 435/SAP has a great potential to be used in the continuous biodiesel apparatus such as the fixed bed reactor.Graphical abstractOperational stability of pure Novozym 435 and Novozym 435/SAP.
Co-reporter:Jie Zha
The Journal of Physical Chemistry C 2015 Volume 119(Issue 1) pp:420-425
Publication Date(Web):December 16, 2014
DOI:10.1021/jp510010d
The effect of thermal treatment on surface wettability of polysiloxane coatings was fully studied. In contrary to the enhanced hydrophobicity of methyltrimethoxysilane (MTMS)-based coatings, the water contact angle of tetraethoxysilane (TEOS)-based coatings decreased from 70.8 to 52.8° when temperature increased from 100 to 300 °C. It was confirmed by FT-IR, solid state 29Si NMR, and X-ray photoelectron spectroscopy measurements that compared with MTMS-based coatings, that TEOS-based coatings consisted of more silanol groups, most of which were in the form of intramolecular hydrogen bonds. The further condensation at higher temperature led to a rupture of these intramolecular hydrogen bonds, resulting in high surface free energy and thus hydrophilic surface. Besides, this hydrogen bonding effect on wettability was weakened as the content of MTMS went up in MTMS/TEOS hybrid coatings.
Co-reporter:Xin Lu, Yuhui Hou, Jie Zha, and Zhong Xin
Industrial & Engineering Chemistry Research 2014 Volume 53(Issue 38) pp:14659-14663
Publication Date(Web):September 12, 2014
DOI:10.1021/ie502146k
A two-step acid–base catalyzed sol–gel method has been used to prepare monodispersed poly(3-mercaptopropylsilsesquioxane) (PMPSQ) microspheres. Initially, the hydrolysis of 3-mercaptopropyltrimethoxysilane was catalyzed by hydrochloric acid in an aqueous medium, and then the addition of ammonium hydroxide initiated the condensation of hydrolysate. The formation process of PMPSQ microspheres was characterized by field emission scanning electron microscopy and 29Si NMR. The formation mechanism of the monodispersed microspheres was also discussed. Through this method, monodispersed PMPSQ microspheres with a high yield were achieved and the particle size could be adjusted by changing the precursor concentration.
Co-reporter:Xin Lu, Yuhui Hou, Jie Zha, and Zhong Xin
Industrial & Engineering Chemistry Research 2013 Volume 52(Issue 17) pp:5880-5886
Publication Date(Web):March 11, 2013
DOI:10.1021/ie302556t
Rhodamine B-doped poly(3-mercaptopropylsilsesquioxane) (RB-PMPSQ) fluorescent microspheres with thiol groups were prepared by a facile sol–gel method. Initially, 3-mercaptopropyltrimethoxysilane (MPTMS) monomer was hydrolyzed in an aqueous acid solution with rhodamine B (RB) as the hydrolysis catalyst and the fluorescent dye at the same time, and then an ammonia solution was added into the reaction solution to catalyze the condensation reactions of silanol. Through this method, a high yield of RB-PMPSQ fluorescent microspheres with narrow distribution of particle sizes was obtained, and the size of the particles could be effectively controlled depending upon the concentration of the monomer. The morphology and the fluorescent property of RB-PMPSQ microspheres were characterized by scanning electron microscopy (SEM) and fluorescence spectrophotometer, respectively. The fluorescent microspheres showed excellent photostability. The formation mechanism of the fluorescent microspheres was also proposed.
Co-reporter:Jiaying Zhang, Zhong Xin, Xin Meng, Yuhao Lv, and Miao Tao
Industrial & Engineering Chemistry Research 2013 Volume 52(Issue 41) pp:14533-14544
Publication Date(Web):2017-2-22
DOI:10.1021/ie401708h
Several nickel-incorporated SiO2 catalysts with MoO3 molar content in range of 0.5% to 5.0% were prepared by the hydrothermal synthesis method and investigated for synthetic natural gas (SNG) production in a continuous flow fixed-bed reactor. MoO3 can significantly improve the activity of Ni-SiO2 due to electron transfer from MoO3 to Ni species, while excessive MoO3 (>3.0%) will reduce the catalyst activity due to partial coverage of active metal by MoO3 and formation of Ni–Mo alloy. Ni-0.5%Mo-SiO2 achieves the best activity with 100% CO conversion and ∼99% CH4 yield at 400 °C, 2.0 MPa, and 12000 mL/g/h. The results of thermogravimetry (TG) and temperature-programming reduction (TPR) show that MoO3 can inhibit carbon deposition of Ni-SiO2 and excessive MoO3 (>1.0%) will weaken the interaction between metallic nickel and the support. The results of XRD, TPR, and TG show that catalyst sintering rather than carbon deposition leads to catalyst deactivation in catalytic stability and thermal stability tests.
Co-reporter:Changlu Zhou, Xin Lu, Zhong Xin, Juan Liu, Yanfeng Zhang
Progress in Organic Coatings 2013 Volume 76(Issue 9) pp:1178-1183
Publication Date(Web):September 2013
DOI:10.1016/j.porgcoat.2013.03.013
•A benzoxazine-cured epoxy (EPB) coating was prepared by a thermal curing method.•Water contact angles of all EPB coatings were more than 98°.•EPB coatings performed excellent corrosion protection for mild steel.•Presence of hydrogen-bonding network in EPB coatings was characterized by FTIR.A hydrophobic benzoxazine-cured epoxy coating (EPB) was prepared by a dip coating and thermal curing method using benzoxazine monomer (B-TMOS) as curing agent. Fourier transform infrared (FTIR) analyses confirmed the presence of thermal curing reactions and hydrogen-bonding interactions in the epoxy/polybenzoxazine system. The hydrophobicity of epoxy coatings induced by the incorporation of B-TMOS was enhanced significantly, and the water contact angles of resultant EPB coatings were higher than 98°. The corrosion protection ability of epoxy coatings was investigated by open-circuit potentials, potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) methods. The results showed that the charge transfer resistance (Rct) of EPB coatings was increased by about three orders of magnitude compared with bare mild steel, and the protection efficiency values of all EPB samples were more than 98%. This increased corrosion protection property could be attributed to the high hydrophobic performance of EPB coatings.
Co-reporter:Juan Liu, Xin Lu, Zhong Xin, and Changlu Zhou
Langmuir 2013 Volume 29(Issue 1) pp:411-416
Publication Date(Web):December 6, 2012
DOI:10.1021/la303730m
A series of low surface free energy silane-functional polybenzoxazine films were prepared from alkylphenol, paraformaldehyde, and 3-aminopropyltrimethoxysilane (3-APTMOS) using a facile one-step thermal curing method. The chemical structures of these benzoxazine monomers were confirmed by FTIR and 1H NMR. The surface properties of the series of polybenzoxazine films were proved through contact angle measurement, and the lowest surface energy of these films was 14.91 mJ/m2. Moreover, the hydrogen bond network of the polybenzoxazine systems was studied using the FTIR spectra. The result showed that the intramolecular hydrogen bonding transformed into intermolecular hydrogen bonding with increasing curing time. Based on these findings, the transformation mechanism between the intermolecular and intramolecular hydrogen bonding during the progress of curing was proposed. The thermogravimetric analysis (TGA) results indicated that the silane-functional polybenzoxazine, with a high char yield of 57.01%, possessed excellent thermal stability.
Co-reporter:Jun Zhou
Polymer Composites 2012 Volume 33( Issue 3) pp:371-378
Publication Date(Web):
DOI:10.1002/pc.22157
Abstract
Relationship between molecular structure and nucleation of benzylidene acetals in isotactic polypropylene was investigated by differential scanning calorimeter and two-dimensional correlative infrared spectra. The results indicated that benzylidene acetals can dissolve into isotactic polypropylene at high temperature and form nuclei to induce the crystallization of isotactic polypropylene at low temperature. The solubility of benzylidene acetals depend on the number of hydroxyl, but the nucleation of benzylidene acetals depend on the number of benzylidene, which could interact with methyl of isotactic polypropylene. The latter intermolecular interaction makes the infrared absorbance of methyl change before that of skeleton C-C and methine of isotactic polypropylene in the induction period of crystallization. The order is opposite in the induction period of crystallization of virgin isotactic polypropylene. Then, new efficient nucleating agents for isotactic polypropylene can be designed by changing the number of hydroxyl and benzylidene of benzylidene acetals. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers
Co-reporter:Huijie Dong;Xin Lu;Li Qu
Polymer Composites 2012 Volume 33( Issue 8) pp:1313-1320
Publication Date(Web):
DOI:10.1002/pc.22257
Abstract
A novel type of polybenzoxazine (PB-m)/clay nanocomposites were prepared from 2-bis (3-methyl-3,4-dihydro-2H-1,3-benzoxazinyl) propane (B-m) and di-methyl, di-octadecyl ammonium chloride (DODMAC)-modified clay. Surface properties and thermal stability of the PB-m/clay nanocomposites were characterized by contact angle measurement and thermogravimetry (TGA), respectively. It was found that the PB-m/clay nanocomposites possess the lowest surface free energy (15.27 mJ/m2) after 8 h curing at 210°C, which is even lower than that of poly (tetrafluoroethylene) (21.0 mJ/m2), and the presence of the clay in the B-m PB-m matrix enhances the stability of the surface energy at 210°C. FTIR results show that the intercalated structures of PB-m/clay nanocomposites have no influence on the hydrogen-bonding network of the PB-m during curing. Combining with the results of atomic force microscope, it can be concluded that the stability of surface energies of the PB-m/clay nanocomposites is mainly affected by the migration and masking of clay. Also, TGA results show that the addition of clay improves the thermal stability of PB-m. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers
Co-reporter:Shicheng Zhao;Jing Zhang ;Ting Han
Journal of Applied Polymer Science 2012 Volume 123( Issue 1) pp:617-626
Publication Date(Web):
DOI:10.1002/app.34527
Abstract
Combined effect of α-nucleating agent (NA) sodium 2,2′-methylene-bis(4,6-di-tert-butylphenyl) phosphate (NA11) and nanoclay (NC) on the mechanical properties and crystallization behavior of isotactic polypropylene (iPP) was investigated by mechanical testing, wide-angle X-ray scattering (WAXD), differential scanning calorimetry (DSC), polarized optical microscopy (POM), and scanning electron microscopy (SEM). The mechanical testing results indicated that the separate addition of NA11 and NC only increased the stiffness of iPP while the combined addition of NA11, NC, and maleic anhydride grafted polypropylene (PP-g-MA) simultaneously improved stiffness and toughness of iPP. Compared to pure iPP, the tensile strength, the flexural modulus, and impact strength of iPP composites increased 9.7, 38.6, and 42.9%, respectively. The result indicated good synergistic effects of NC, NA11, and PP-g-MA in improving iPP mechanical properties. WAXD patterns revealed NA11, and NC only induced the α-crystals of iPP. SEM micrograph showed that the PP-g-MA could effectively improve the dispersing of NC in iPP. Finally, the nonisothermal crystallization kinetics of neat iPP and PP nanocomposites was described by Caze method. The result indicated that the addition of NA overcame the shortcoming of low crystallization rate of NC nanocomposites and maintained the excellent mechanical properties, which is another highlight of the combined addition of NAs and nanoclay. Meanwhile, the result showed that nuclei formation and spherulite growth of iPP were affected by the presence of NA and nanoclay. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Co-reporter:Shicheng Zhao;Na Xu;Changquan Jiang
Journal of Applied Polymer Science 2012 Volume 123( Issue 1) pp:108-117
Publication Date(Web):
DOI:10.1002/app.34441
Abstract
A novel highly efficient β-nucleating agent for isotactic polypropylene (iPP), hexahydrophthalic barium (HHPA-Ba), was found and its effects on the mechanical properties, the β-phase content, and crystallization behavior of iPP were investigated, respectively. The results show that the β-phase content of nucleated iPP (kβ value) can reach 80.2% with 0.4 wt % HHPA-Ba. The impact strength and crystallization peak temperature of nucleated iPP are greatly increased. Compared with pure iPP, the impact strength of nucleated iPP can increase 2.4 times. Meanwhile, the spherulite size of nucleated iPP is dramatically decreased than that of pure iPP. The Caze method was used to investigate the nonisothermal crystallization kinetics of nucleated iPP and the crystallization active energy was achieved by Kissinger method. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Co-reporter:Yaoqi Shi
Journal of Applied Polymer Science 2012 Volume 125( Issue 4) pp:2963-2969
Publication Date(Web):
DOI:10.1002/app.36236
Abstract
In this work, 2,2′-methylene-bis-(4,6-di-t-butylphenylene)phosphate lithium (NA03) was synthesized and its crystal structural characterization was obtained by single crystal X-ray diffusion. The crystal data showed geometrically the cell parameter of NA03 matched with isotactic polypropylene (iPP), the a cell dimension was about two times to the value of cell edge of (010)iPP. The disregistry was 2.89%, which was under the upper limit between the lattice matching spacing of host and guest crystals. Then NA03 was proved to be a highly effective nucleating agent for iPP through studying crystallization behaviors, crystallization morphologies, and mechanical properties of iPP nucleated with NA03. The outstanding nucleation efficiency could be attributed to the lattice matching between nucleating agent and iPP. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Co-reporter:Lin Li, Jun-Hua Wang, Zhong Xin
European Polymer Journal 2011 Volume 47(Issue 9) pp:1795-1803
Publication Date(Web):September 2011
DOI:10.1016/j.eurpolymj.2011.06.011
A novel poly (methyl methacrylate-co-2-methacryloyloxyethyl phosphorylcholine-co-tris(trimethylsiloxy)-3-methacryloxypropylsilane) terpolymer (PMMT) was synthesized and the anti-biofouling properties were studied in order to evaluate the potential of this silicone hydrogel to be used as contact lens material. The chemical structure was characterized by IR, 1H-NMR and elemental analysis. Poly methyl methacrylate (PMMA) and poly (methyl methacrylate-co-tris (trimethylsiloxy)-3-methacryloxypropylsilane) (PMT) were also synthesized to compare with PMMT. Protein adsorption measurement showed that for PMMT-2 membrane (MPC: 16.6 mol%), the amount of adsorbed proteins was decreased by 75.3% and 76.8% compared with PMMA and PMT membranes, respectively. SEM pictures showed clearly that PMMT films suppressed the adhesion of platelets. Water structure in polymers was determined by differential scanning calorimetry, and PMMT-2 possessed more freezing water content than PMMT-1 (MPC: 14.5 mol%). The equilibrium water content of PMMT-2 membrane reached 55%, which might offer comfortable wear feeling, and the introduction of MPC increased the wettability of the polymer surface dramatically. Both the terpolymers PMMT-1 and PMMT-2 exhibited high transparency (relatively constant at approximately 96%) in the visible light wave range. Moreover, oxygen transmissibility (Dk/t) of the terpolymers met the requirement for a lens to be worn safely overnight. It could be concluded that the novel silicone hydrogel containing MPC unit was an effective candidate material for making biomaterials, particularly for contact lenses.Graphical abstractHighlights► The wettability of the polymer surface was improved by the introduction of MPC. ► The amount of adsorbed proteins was reduced by the introduction of MPC unit. ► The films exhibited high transparency (96%) in the visible light wave range. ► TRIS unit played a valuable role to improve the oxygen transmissibility.
Co-reporter:Li Qu and Zhong Xin
Langmuir 2011 Volume 27(Issue 13) pp:8365-8370
Publication Date(Web):June 8, 2011
DOI:10.1021/la200073v
A novel fluorinated silane-functional benzoxazine monomer is synthesized, and the structure is characterized by FTIR and 1H NMR. Chemical bonds Si–O–Si linkage between the benzoxazine monomer and the substrate are identified through the variation of water contact angles. The low surface free energy calculation and mechanism of the benzoxazine polymer films are proved through contact angle measurement and FTIR. The film formation property and thermal stability of the polybenzoxazine are also investigated. These results clearly show that this novel polybenzoxazine can not only bond to the substrate but also possess even lower surface free energy which is 15.5 mJ/m2. The polymer also possesses well thermal stability with a glass transition temperature of 188 °C and the 5% weight loss temperatures of 276 °C.
Co-reporter:Huijie Dong, Zhong Xin, Xin Lu, Yuhao Lv
Polymer 2011 Volume 52(Issue 4) pp:1092-1101
Publication Date(Web):17 February 2011
DOI:10.1016/j.polymer.2011.01.009
In our study, the effect of N-substituents on the surface free energy and hydrogen bonding network structure of polybenzoxazine has been studied systematically. The contact angle measurement results show the surface energies of the polybenzoxazines decrease with the increase of alkyl chain length, and are not affected by the steric factor of the tert-butyl group. However, the FTIR curve fitting results show that both the chain length and bulkiness of alkyl group have an effect on the hydrogen bonding network of the polybenzoxazines, and facilitate the formation of intermolecular hydrogen bonding during the progress of cure. This indicates that both alkyl group and the fraction of intermolecular hydrogen bonding have an effect on the surface energy of the polybenzoxazines. Additionally, the transformation mechanism of the intermolecular and intramolecular hydrogen bonding during the progress of cure is proposed for the first time.
Co-reporter:Xin Meng, Zhong Xin, Xue-feng Wang
Polymer Degradation and Stability 2010 Volume 95(Issue 10) pp:2076-2081
Publication Date(Web):October 2010
DOI:10.1016/j.polymdegradstab.2010.06.028
This work deals with the antioxidant activity of benzofuranone compounds in polypropylene (PP). The antioxidant activities of ten benzofuranone compounds in PP were compared using melt flow index (MFI) values of PP stabilized by benzofuranone compounds primarily. The results show: firstly, that the increase of electron donating ability of substituent in 3-substituted benzene ring is beneficial to the improvement of antioxidant activity. Secondly, it has been verified that the steric hindrance of 2′-position substituent can weaken the antioxidant activity of benzofuranone. But when 2′-position substituent forms a hydrogen bond with 3-position reactive hydrogen, the steric hindrance is offset efficiently. Finally, the methyl and tert-butyl groups in the 5 and 7-position of parent benzene ring do not affect the antioxidant activity of benzofuranone compounds in PP obviously.
Co-reporter:Jiangbo Wang
Journal of Applied Polymer Science 2010 Volume 115( Issue 1) pp:330-337
Publication Date(Web):
DOI:10.1002/app.31129
Abstract
The polymethylphenylsilsesquioxane (PMPSQ) microspheres were used as an additive for the injection-molding of polycarbonate (PC) in order to obtain a flame retardant polymer and to damage the other properties of PC as low as possible. The results showed that PMPSQ microspheres were a kind of effective flame retardant by the LOI test and the flame retardancy of PC increased with the increase of PMPSQ content. Thermogravimetric analysis suggested that the PMPSQ could induce crosslinking reactions and accelerate the thermal degradation of PC, sequentially promote the formation of the residue char during degradation. Differential scanning calorimetry measurement showed that the glass transition temperature of PC/PMPSQ system was decreased with the increase of PMPSQ content, which maybe caused by the enlarged free volume of PC-rich phase. The rheological behaviors including dynamic and steady modes, combined with the analysis of scanning electron microscopy photographs, exhibited that the dispersion and compatibility of PMPSQ in the PC matrix decreased the viscosity of the systems and the addition of PMPSQ microspheres improved the processability of PC, but still there exist aggregation of PMPSQ microspheres in PC matrix, which gave a higher impact strength but a lower flexural modulus and elongation at break than pure PC. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Co-reporter:Zhi Cai;Shicheng Zhao;Benxian Shen
Journal of Applied Polymer Science 2010 Volume 116( Issue 2) pp:792-800
Publication Date(Web):
DOI:10.1002/app.31486
Abstract
The mechanical and optical properties of iPP nucleated with bicyclo[2.2.1]heptenedicarboxylate salts (BCHED) have been investigated. The results showed that aluminum bicyclo[2.2.1]heptenedicarboxylate (BCHE13) is the most effective nucleating agent to improve the mechanical and optical properties. Then the effects of the BCHE13 concentration on mechanical and optical properties and crystallization behaviors were studied. The results indicated that the saturated concentration of BCHE13 is about 0.2 wt %, at which nucleated iPP showed the better comprehensive mechanical and optical properties and high crystallization peak temperature. Nonisothermal crystallization kinetics of iPP nucleated with different BCHE13 contents have been investigated by Caze method. The results indicated Avrami exponents of nucleated iPP gradually increased with the increasing of BCHE13 concentration. The results can be explained that crystallization and growth model of nucleated iPP is heterogeneous nuclei followed by more than three-dimension spherical growth during nonisothermal crystallization, which can be proved by agglomeration of BCHE13 in melt iPP. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Co-reporter:Shicheng Zhao
Journal of Polymer Science Part B: Polymer Physics 2010 Volume 48( Issue 6) pp:653-665
Publication Date(Web):
DOI:10.1002/polb.21935
Abstract
Nucleation characteristics of isotactic polypropylene (iPP) nucleated by the α/β compounded nucleating agents (NAs) were investigated by wide-angle X-ray scattering, differential scanning calorimetry and mechanical testing. The results showed that the nucleation effect of the α/β compounded NAs depends on not only nucleation efficiency (NE) of individual β and α NAs and their ratios but also the processing conditions, especially the cooling rates. The nucleating characteristics of the α/β compounded NAs can be illustrated by competitive nucleation. The NA with high NE played a leading role during iPP crystallization even at a low weight ratio and at different cooling rates. The stiffness and toughness of iPP can be simultaneously improved by using suitable compositions at the appropriate ratios. Finally, the nonisothermal crystallization kinetics of iPP nucleated with the α/β compounded NAs was described by Caze method and the crystallization activation energy of nucleated iPP was calculated by Kissinger equation. The result indicated that the crystal growth pattern of nucleated iPP was heterogeneous nucleation followed by three-dimension spherical growth. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 653–665, 2010
Co-reporter:Liang Wen;Dongkang Hu
Journal of Polymer Science Part B: Polymer Physics 2010 Volume 48( Issue 11) pp:
Publication Date(Web):
DOI:10.1002/polb.22014
Abstract
A novel nucleating agent (TBC8-t), self-assembled with p-tert-butylcalix[8]arene (TBC8) and toluene, was used to manipulate the crystallization behavior of poly(L-lactic acid) (PLLA). Toluene molecules were used to adjust the crystallization structure of TBC8. Differential scanning calorimetry results show that the crystallization peak temperature (Tc) and crystallization rate (ΔHc/time) of PLLA nucleated with TBC8-t are 132.3 °C and 0.24 J/gs, respectively, which are much higher than that with conventional nucleating agent-talc (Tc = 119.3 °C, ΔHc/time = 0.13 J/gs). The results of polarized optical microscopy demonstrate that TBC8-t could greatly enhance the crystallization rate of PLLA by increasing the nucleation rate rather than crystal growth rate. Along with an improvement of the crystallization rate, the crystalline morphology of PLLA is also affected by TBC8-t. The addition of TBC8-t transforms most of the original spherulite crystals into sheaf-like crystals. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1235–1243, 2010
Co-reporter:Liping Zhang, Shuzhen Sun, Zhong Xin, Boyang Sheng, Qun Liu
Fuel 2010 Volume 89(Issue 12) pp:3960-3965
Publication Date(Web):December 2010
DOI:10.1016/j.fuel.2010.06.030
The transesterification of palm oil and dimethyl carbonate (DMC) for preparing biodiesel has been carried out at the catalysis of immobilized-lipase in solvent-free system. The components were all confirmed by GC and GC–MS analysis. The fatty acid methyl esters (FAMEs) were analyzed with internal standard method. The fatty acids glycerol carbonate esters (FAGCs) were characterized as the intermediates. And, glycerol dicarbonate (GDC) was confirmed as the byproduct by comparing with the model compound. Moreover, the effects of the reaction conditions (type of lipases, molar ratio of DMC and palm oil, amount of catalyst, reaction temperature and time) on the yield of FAMEs were investigated. The yield of FAMEs could reach 90.5% at 55 °C for 24 h with the molar ratio of DMC to oil 10:1 and the catalyst amount of 20% Novozym 435 (based on the oil weight). There was no obvious loss in the FAMEs yield after Novozym 435 having been used for eight cycles.
Co-reporter:Xin Meng
Science Bulletin 2010 Volume 55( Issue 1) pp:27-31
Publication Date(Web):2010 January
DOI:10.1007/s11434-009-0691-4
The rate constants for the hydrogen donation of three 3-aryl-benzofuranone compounds with tert-butoxyl radicals have been calculated through laser flash photolysis (LFP) technique, which were used to evaluate the hydrogen donating abilities of those 3-aryl-benzofuranone compounds. The antioxidant activities of those 3-aryl-benzofuranone compounds in polypropylene (PP) have been studied using the oxidation induction time (OIT) of PP stabilized by those 3-aryl-benzofuranone compounds too. It has been found that the methyl group on the 2′-position can prevent the hydrogen donation of 3-aryl-benzofuranone with tert-butoxyl radicals and weakens the antioxidant activity of 3-aryl-benzofuranone in the oxidation of PP, i.e., the greater is the hydrogen donating ability of 3-aryl-benzofuranone with radicals, the better is the antioxidant activity of 3-aryl-benzofuranone in the oxidation of PP in the presence of oxygen.
Co-reporter:Shicheng Zhao
Journal of Applied Polymer Science 2009 Volume 112( Issue 3) pp:1471-1480
Publication Date(Web):
DOI:10.1002/app.29689
Abstract
Bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylate salts (BCHED) were synthesized by hydrothermal method. The crystallization kinetics of isotactic polypropylene (iPP) and nucleated iPP with BCHED were investigated by differential scanning calorimeter (DSC) under isothermal and nonisothermal conditions. Isothermal crystallization kinetics was described by Avrami equation and the fold surface free energy (σe) of iPP was calculated by Hoffman theory. The results showed Avrami exponents of nucleated iPP become smaller, the values of t1/2 dramatically decrease, the crystallization rate constants Z(T) greatly increase and the fold surface free energy (σe) of iPP decrease with the addition of the nucleating agents. Under nonisothermal condition the Caze method was applied to deal with the crystallization kinetics of iPP and the crystallization active energy of iPP was determined by Kissinger method. The results showed the crystallization peak temperatures (Tcp) of nucleated iPP greatly increase, but Avrami exponents of iPP were slightly influenced and the crystallization active energy of iPP increases by the addition of BCHED. It can be concluded that BCHED act as nucleating agents and BCHE11 shows the best nucleating effect. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Co-reporter:Shidong Tang, Zhong Xin
Polymer 2009 50(4) pp: 1054-1061
Publication Date(Web):
DOI:10.1016/j.polymer.2008.12.015
Co-reporter:Jiangbo Wang
Frontiers of Chemical Science and Engineering 2009 Volume 3( Issue 2) pp:167-171
Publication Date(Web):2009 June
DOI:10.1007/s11705-009-0006-y
The thermal degradation behaviors of polycarbonate/polymethylphenylsilsesquioxane (FRPC) composites were investigated by thermogravimetric analysis (TGA) under isothermal conditions in nitrogen atmosphere. The isothermal kinetics equation was used to describe the thermal degradation process. The results showed that activation energy (E), in the case of isothermal degradation, was a quick increasing function of conversion (α) for polycarbonate (PC) but was a strong and decreasing function of conversion for FRPC. Under the isothermal condition, the addition of polymethylphenylsilsesquioxane (PMPSQ) retardanted the thermal degradation and enhanced the thermal stability of PC during the early and middle stages of thermal degradation. It also indicated a possible existence of a difference in nucleation, nuclei growth, and gas diffusion mechanism in the thermal degradation process between PC and FRPC. Meanwhile, the addition of PMPSQ influenced the lifetime of PC, but the composite still met the demand in manufacturing and application.
Co-reporter:Xin Meng, Zhong Xin, Yongrong Li, Zhi Cai
Polymer Degradation and Stability 2007 Volume 92(Issue 1) pp:184-188
Publication Date(Web):January 2007
DOI:10.1016/j.polymdegradstab.2006.07.024
The hydrogen donation kinetics of four 3-aryl-benzofuranones with different chemical structures toward tert-butoxyl radicals were studied using laser flash photolysis (LFP) technique. The rate constants of hydrogen reactions, which can be used to evaluate the hydrogen donating abilities of 3-aryl-benzofuranones toward radicals, were obtained. The results showed that the position of substituted methyl group has a very important effect on the hydrogen donating ability of benzofuranone toward tert-butoxyl radicals, i.e. if the methyl group is on 2′-position, the hydrogen donation of 3-aryl-benzofuranone toward tert-butoxyl radicals will be prevented and the hydrogen donating ability will be weakened.
Co-reporter:Xin Lu
Colloid and Polymer Science 2007 Volume 285( Issue 5) pp:599-604
Publication Date(Web):2007 February
DOI:10.1007/s00396-006-1609-1
A procedure has been developed to coat micron-sized poly(styrene-co-3-trimethoxysilyl propyl methacrylate) microspheres with a smooth layer of polysiloxane by the hydrolysis and condensation of methyl trimethoxylsilane (MTMS). Firstly, polystyrene microspheres containing silanol groups were prepared by conventional dispersion polymerization using 3-(trimethoxysilyl) propyl methacrylate (MPS) as a functional comonomer in an ethanol/water medium. Secondly, the synthesis of the polysiloxane shell was carried out using a sol–gel process of MTMS. The thickness of the shells can be easily varied with different copolymer seeds and MTMS feed ratio. When we used copolymer particles with 2.00 μm diameter as seeds, the thickness of the polysiloxane shells can be varied from 0.10 to 0.18 μm. The core/shell structure of the composite microspheres was characterized by transmission electron microscope (TEM).
Co-reporter:Yue-Fei Zhang
Journal of Polymer Science Part B: Polymer Physics 2007 Volume 45(Issue 5) pp:590-596
Publication Date(Web):24 JAN 2007
DOI:10.1002/polb.21072
Sodium 2,2′-methylene-bis(4,6-di-tert-butylphenyl) phosphate (NA40) and N,N-dicyclohexylterephthalamide (NABW) are high effective nucleating agents for inducing the formation of α-isotactic polypropylene (α-iPP) and β-iPP, respectively. The isothermal crystallization kinetics of iPP nucleated with nucleating agents NABW, NA40/NABW (weight ratio of NA40 to NABW is 1:1) and NA40 were investigated by differential scanning calorimetry (DSC) and Avrami equation was adopted to analyze the experimental data. The results show that the addition of NABW, NA40/NABW and NA40 can shorten crystallization half-time (t1/2) and increase crystallization rate of iPP greatly. In these three nucleating agents, the α nucleating agent NA40 can shorten t1/2 of iPP by the largest extent, which indicates that it has the best nucleation effect. While iPP nucleated with NA40/NABW compounding nucleating agents has shorter t1/2 than iPP nucleated with NABW. The Avrami exponents of iPP and nucleated iPP are close to 3.0, which indicates that the addition of nucleating agents doesn't change the crystallization growth patterns of iPP under isothermal conditions and the crystal growth is heterogeneous three-dimensional spherulitic growth. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 590–596, 2007
Co-reporter:Xin Meng, Weiguang Gong, Zhong Xin, Zhi Cai
Polymer Degradation and Stability 2006 Volume 91(Issue 12) pp:2888-2893
Publication Date(Web):December 2006
DOI:10.1016/j.polymdegradstab.2006.08.025
The antioxidant activities of four benzofuranones in melt processing of polypropylene (PP) have been investigated using multiple extrusions. The antioxidant activities of those four benzofuranones with different substituent groups have been evaluated using melt flow index (MFI) and yellowness index (Y.I.) of multiple-extruded PP stabilized with those antioxidants. The change of MFI values indicates as follows: firstly, the position of substituent group has a very important effect on the antioxidant activity of benzofuranone in the melt processing of PP i.e. methyl group of 2′-position may prevent the hydrogen donation of benzofuranone toward PP radicals and make the antioxidant activity of benzofuranone in PP decrease; secondly, electronic property of substituent group of para position to 3-reactive hydrogen has little influence on the antioxidant activity. Furthermore, the theory that the formation of antioxidative products due to the dimerization and disproportionation of benzofuranyl radicals is the main reason that induces the discoloration of stabilized PP has been predicted for the first time.
Co-reporter:Yue-Fei Zhang;Yue-Fei Zhang
Journal of Applied Polymer Science 2006 Volume 100(Issue 6) pp:4868-4874
Publication Date(Web):29 MAR 2006
DOI:10.1002/app.23209
Nucleation effects of 2,2′-methylene-bis (4,6-di-tert-butylphenyl) phosphate metal salts as a nucleating agent for isotactic polypropylene (iPP) were investigated with differential scanning calorimeter and polarized optical microscope, and their effects on mechanical, optical, and heat resistance properties of iPP were also studied. The results showed that monovalent metal salts of substituted aromatic heterocyclic phosphate such as sodium salt, lithium salt, and potassium salt had a good performance. With 0.2 wt % of sodium salt, lithium salt, or potassium salt incorporated into iPP, the crystallization peak temperature of iPP could be increased by 13.5, 13.6, and 15.0°C, respectively; the mass fraction of crystallinity of iPP could be increased by about 5%; and crystallization rate was enhanced increasingly. Meanwhile the tensile strength and flexural modulus of iPP could be increased by about 10 and 30%, respectively, and the clarity and heat distortion temperature of iPP could also be improved significantly. But bivalent and trivalent metal salts of substituted aromatic heterocyclic phosphate had little effect on properties of iPP. Meanwhile the morphology study showed that the addition of monovalent sodium salt could decrease the spherulite size of iPP significantly. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4868–4874, 2006
Co-reporter:Yue-fei Zhang
Journal of Applied Polymer Science 2006 Volume 101(Issue 5) pp:3307-3316
Publication Date(Web):22 JUN 2006
DOI:10.1002/app.23883
The crystallization kinetics of isotactic polypropylene (iPP) and nucleated iPP with substituted aromatic heterocyclic phosphate salts were investigated by means of a differential scanning calorimeter under isothermal and nonisothermal conditions. During isothermal crystallization, Avrami equation was used to describe the crystallization kinetics. Moreover, kinetics parameters such as the Avrami exponent n, crystallization rate constant Zt, and crystallization half-time t1/2 were compared. The results showed that a remarkable decrease in t1/2 as well as a significant increase in overall crystallization rate was observed in the presence of monovalent salts of substituted aromatic heterocyclic phosphate, while bivalent and trivalent salts have little effect on crystallization rate of iPP. The addition of monovalent metal salts could decrease the interfacial free energy per unit area perpendicular to PP chains σe value of iPP so that the nucleation rate of iPP was increased. During nonisothermal crystallization, Caze method was used to analyze the crystallization kinetics. It also showed that monovalent metal salts had better nucleation effects than bivalent and trivalent metal salts. From the obtained Avrami exponents of iPP and nucleated iPP it could be concluded that the addition of different nucleating agents changed the crystal growth pattern of iPP. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3307–3316, 2006
Co-reporter:Changlu Zhou, Xin Lu, Zhong Xin, Juan Liu, Yanfeng Zhang
Progress in Organic Coatings (September 2013) Volume 76(Issue 9) pp:1178-1183
Publication Date(Web):1 September 2013
DOI:10.1016/j.porgcoat.2013.03.013
•A benzoxazine-cured epoxy (EPB) coating was prepared by a thermal curing method.•Water contact angles of all EPB coatings were more than 98°.•EPB coatings performed excellent corrosion protection for mild steel.•Presence of hydrogen-bonding network in EPB coatings was characterized by FTIR.A hydrophobic benzoxazine-cured epoxy coating (EPB) was prepared by a dip coating and thermal curing method using benzoxazine monomer (B-TMOS) as curing agent. Fourier transform infrared (FTIR) analyses confirmed the presence of thermal curing reactions and hydrogen-bonding interactions in the epoxy/polybenzoxazine system. The hydrophobicity of epoxy coatings induced by the incorporation of B-TMOS was enhanced significantly, and the water contact angles of resultant EPB coatings were higher than 98°. The corrosion protection ability of epoxy coatings was investigated by open-circuit potentials, potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) methods. The results showed that the charge transfer resistance (Rct) of EPB coatings was increased by about three orders of magnitude compared with bare mild steel, and the protection efficiency values of all EPB samples were more than 98%. This increased corrosion protection property could be attributed to the high hydrophobic performance of EPB coatings.
Co-reporter:Liang WEN, Zhong XIN
Chinese Journal of Chemical Engineering (December 2010) Volume 18(Issue 6) pp:899-904
Publication Date(Web):1 December 2010
DOI:10.1016/S1004-9541(09)60145-2
The effect of a novel active nucleating agent (TBC8-eb) on the isothermal crystallization of poly(L-lactic acid) (PLLA) was studied by differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). The analysis on kinetics demonstrates that TBC8-eb can not only accelerate the crystallization rate but also transform most of the original spherulite crystals of PLLA into sheaf-like crystals. Furthermore, the free energy of folding (σe) of PLLA and PLLA with TBC8-eb is 0.15 and 0.06 J·m−2, respectively, which suggests that the addition of TBC8-eb favors the regular folding of molecule chains in the crystallization of PLLA, improving its crystallization rate. The FTIR results show that TBC8-eb can accelerate the conformational ordering of PLLA in the isothermal crystallization. The conformational ordering of PLLA nucleated with TBC8-eb begins with the interchain interaction of CH3, and then a short helix emerges where a couple of CH3 groups interact.
Co-reporter:Jiahui Gu, Zhong Xin, Xin Meng, Shuzhen Sun, Qingan Qiao, Hongbo Deng
Journal of Food Engineering (August 2016) Volume 182() pp:1-8
Publication Date(Web):1 August 2016
DOI:10.1016/j.jfoodeng.2016.01.026
•Zein extracted from DDGS was used for the development of human food.•A reduced-pressure distillation method was used to produce zein-based fat analogue.•Xanthan gum was used as the anti-aggregating reagent.•Zein-based fat analogue was applied in mayonnaise.In this study, the zein extracted from distillers dried grains with solubles (DDGS) is utilized to produce a fat analogue, by employing a simple ”reduced-pressure distillation microparticulation“ method. The optimal conditions for preparing the fat analogue are as follows: a zein concentration of 3 w/v% (based on 60 v/v% ethanol water), an agitator speed of 200 rpm, a xanthan gum amount of 20 wt% (based on zein mass) and a heating temperature of 50 °C. The zein-based fat analogue obtained has a volume-weighted mean diameter (D[4, 3]) of about 16 μm, which is then applied in the formulation of mayonnaise, at fat substitution ratios of 0% (full-fat), 20%, 40%, 60%, 80% and 100%, respectively. Based on the appearance, stability, total calorific value, as well as rheological, microstructure and sensory analyses, it may be concluded that the fat substitution ratio of no more than 40% is acceptable. This paper illustrates another high-value added use of zein.
Co-reporter:Miao Tao, Xin Meng, Zhong Xin, Zhicheng Bian, Yuhao Lv, Jia Gu
Applied Catalysis A: General (25 April 2016) Volume 516() pp:127-134
Publication Date(Web):25 April 2016
DOI:10.1016/j.apcata.2016.02.019
Co-reporter:Xin Lu, Qiangfeng Yin, Zhong Xin, Zongqian Zhang
Chemical Engineering Science (15 December 2010) Volume 65(Issue 24) pp:6471-6477
Publication Date(Web):15 December 2010
DOI:10.1016/j.ces.2010.10.001
The strong adsorbability of Ag(I) ions onto poly(3-mercaptopropylsilsesquioxane) (PMPSQ) microspheres synthesized through a two-step acid–base catalyzed sol–gel process method was systematically examined. The effect of adsorption time, initial Ag(I) concentration, and solution pH was studied to optimize the Ag(I) adsorbability of PMPSQ microspheres. The PMPSQ microspheres demonstrate a powerful Ag(I) adsorbability with an adsorptivity above 99.99% when the initial Ag(I) concentration is lower than 10 mM and the highest Ag(I) adsorbance of 1140 mg/g at an initial Ag(I) concentration of 150 mM. Adsorption phenomena appeared to follow Langmuir isotherm. The kinetic studies indicated that the adsorption process well fits the pseudo-second-order kinetics with a very rapid initial adsorption rate of 15.28 mg g−1 min−1. The appropriate solution pH for Ag(I) adsorption is around 2.0–5.4. The PMPSQ microspheres demonstrate a promising application in the removal of Ag(I) ions from aqueous solutions.
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