Co-reporter:Peng Liu, Hanying Tang, Ming Lu, Chong Gao, Feng Wang, Yanfen Ding, Shimin Zhang, Mingshu Yang
Polymer Degradation and Stability 2017 Volume 135() pp:1-7
Publication Date(Web):January 2017
DOI:10.1016/j.polymdegradstab.2016.10.013
This article reports a study of the preparation of nanosilica-immobilized antioxidant (SiO2-APTMS-AO) and the thermal oxidative stability of low density polyethylene (LDPE) nanocomposites containing SiO2-APTMS-AO. SiO2-APTMS-AO was prepared based on the fumed nanosilica which was firstly modified with an aminosilane coupling agent and then reacted with 3,5-Di-tert-butyl-4-hydroxybenzoic acyl chloride. Infrared spectroscopy, X-ray photoelectron spectroscopy and thermogravimetric analysis measurements confirmed that the antioxidant group was chemically immobilized onto nanosilica. LDPE/silica nanocomposites were prepared by melt mixing and then pressed into different films. The thermal oxidative stability of the nanocomposites was evaluated by thermogravimetric analysis in air atmosphere, oxidation induction time (OIT) and long-term accelerated thermal aging. The results showed that the SiO2-APTMS-AO can significant improve the thermal oxidative stability of LDPE nanocomposite. Because SiO2-APTMS-AO is based on inorganic nano-filler, in comparison to organic antioxidants, it might have advantages in thermal stability and migration stability during processing and application.
Co-reporter:Yintao Wang, Feng Wang, Quanxiao Dong, Mingchen Xie, Peng Liu, Yanfen Ding, Shimin Zhang, Mingshu Yang, Guoqiang Zheng
Polymer Degradation and Stability 2017 Volume 146(Volume 146) pp:
Publication Date(Web):1 December 2017
DOI:10.1016/j.polymdegradstab.2017.10.017
To enhance the flame-retardant performance of expandable graphite (EG) in rigid polyurethane foam (RPUF), EG particles were encapsulated with inorganic nanoparticles, namely aluminum hydroxide (ATH), forming complex particles EG@ATH with core-shell structure. After the deposition of ATH shell, the expandability of the particles was enhanced from 163 to 197 ml/g, leading to better flame-retardant performance in RPUF. At a content of 11.5 wt%, the limited oxygen index could be increased from 21.5% to 29.6% by EG@ATH, in comparison to 27.5% by the physical mixture of EG and ATH (EG + ATH). Besides, EG@ATH exhibited better performance than EG + ATH on reducing the total smoke release and CO production. It is worth noticing that ATH could react with isocyanate groups, which was confirmed through FTIR. As a result, the interaction between the core-shell particles and the polymer matrix was enhanced, which protected the cell structure of RPUF from destroying by EG particles. The improved flame-retardant performance of EG@ATH, together with their low-cost, easy fabrication and especially friendliness to the environment, make it prospective in applications for flame retardancy of RPUF.A kind of core-shell expandable graphite @ aluminum hydroxide (EG@ATH) as the halogen-free flame retardant for rigid polyurethane foams (RPUF) was designed. This is the first report to prepare encapsulation of expandable graphite with inorganic nanomaterials to increase the expandability. The as-prepared EG@ATH particles showed high efficiency of flame retardancy in RPUF, and improved interface adhesion between EG@ATH particles and RPUF, due to the pre-reaction of ATH layers with polyisocyanate.Download high-res image (198KB)Download full-size image
Co-reporter:Chong Gao, Cunzhe He, Yanfen Ding, Juan Chen, Feng Wang, Peng Liu, Shimin Zhang, Zengxi Li, Mingshu Yang
Fuel 2017 Volume 203(Volume 203) pp:
Publication Date(Web):1 September 2017
DOI:10.1016/j.fuel.2017.05.011
•The organic montmorillonite (OMMT) decreased the yield stress of model waxy oil.•The OMMT decreased the crystallinity and the dimension of the wax crystals.•The OMMT inhibited gelation of the wax crystals.•The OMMT changed the dependence of yield stress on thermal history.To study the influence of organic montmorillonite (OMMT) on the yield stress of the model waxy oil (LMO) under dynamic cooling, OMMT was prepared through ion exchange of the sodium montmorillonite with dimethyldioctadecylammonium chloride (DOAC). The incorporation of OMMT lead to a great reduction of the yield stress, which could be explained by the inhibition effect of OMMT on the wax gelation. For 100 ppm OMMT loading, the yield stress reduced by 74.1% at 36 °C. The inhibition effect was realized through decreasing the wax crystallinity, reducing the crystal dimension and introducing the electrostatic repulsion between the crystal particles. The role of thermal history on the yield stress was also studied. Compared with the pure LMO, the OMMT-doped LMO showed different dependence level on the thermal history, but similar trend with that. High testing temperature and short holding time facilitated a lower yield stress. Due to the presence of different shear stress during cooling, the cooling rate showed a complicated effect on the yielding process.
Co-reporter:Hanying Tang;Quanxiao Dong;Peng Liu;Yanfen Ding;Feng Wang
Science China Chemistry 2016 Volume 59( Issue 10) pp:1283-1290
Publication Date(Web):2016 October
DOI:10.1007/s11426-016-0146-0
In the present work, 3-methacryloxypropyltrimethoxy-silane silanized silica (SiO2-WD70) and 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide immobilized silica (SiO2-WD70-DOPO) nanoparticles were prepared. Silica, SiO2-WD70 and SiO2-WD70-DOPO were incorporated into polypropylene (PP) by melt compounding. Differential scanning calorimetry (DSC), X-ray diffraction (XRD) and polarized optical microscopy (POM) were employed to investigate the isothermal crystallization behavior of PP and PP/silica composites. The kinetic constant (kn), and half crystallization time (t1/2) were calculated by Avrami equation, while the surface free energy of folding was calculated by Lauritzen-Hoffman theory. The increased kn, decreased t1/2 and the surface free energy (σe) in the order of PP, PP/SiO2, PP/SiO2-WD70 and PP/SiO2-WD70-DOPO nanocomposites were attributed to the surface modification of silica. XRD indicated that SiO2-WD70-DOPO addition had no effect on PP crystal structure but accelerated the crystallization rate. POM determined that SiO2-WD70-DOPO addition promoted the nucleation of PP by inducing a higher nucleation density during isothermal conditions. The surface modified nanoparticle SiO2-WD70-DOPO might find possible application as a new type of inorganic nano-sized nucleation agent for PP.
Co-reporter:Chunchun Han, Feng Wang, Chong Gao, Peng Liu, Yanfen Ding, Shimin Zhang and Mingshu Yang
Journal of Materials Chemistry A 2015 vol. 3(Issue 19) pp:5065-5072
Publication Date(Web):27 Apr 2015
DOI:10.1039/C4TC02880E
It is known that ultraviolet (UV) radiation is harmful to human health and affects the long-term stability of many organic materials. It has recently been discovered that blue radiation also poses a danger. In this study, epoxy–ZnO/CdS (EP–ZC) nanocomposites capable of shielding both UV and blue radiation were developed. First, ZnO/CdS nanoparticles were synthesized through the growth of CdS on prefabricated ZnO quantum dots (ZnO QDs). In contrast to ZnO QDs, which only absorb a portion of UV light, the ZnO/CdS nanoparticles exhibited strong absorption over the wavelength region extending from UV light to blue light. Further, their absorption-band range could be controlled by adjusting the Zn/Cd molar ratio. In situ polymerization was employed to prepare the EP–ZC nanocomposites, which were highly transparent at wavelength greater than 500 nm. It was found that the EP–ZC nanocomposites exhibited strong UV-shielding capability and could almost completely block UV light between 200–400 nm as well as more than 80% of the blue light between 400–450 nm when they contained 0.3 wt% ZnO/CdS nanoparticles. Finally, their optical transparency to visible light in the region beyond blue light was the same as that of pure epoxy due to the uniform dispersion of nanoparticles.
Co-reporter:Xinwei Jiang, Feng Wang, Gen Li, Lin Qi, Peng Liu, Yanfen Ding, Shimin Zhang and Mingshu Yang
RSC Advances 2015 vol. 5(Issue 76) pp:62160-62166
Publication Date(Web):20 Jul 2015
DOI:10.1039/C5RA10399A
As a kind of one-dimensional (1D) nanostructured material, nanorod rutile titanium dioxide (TiO2) with high surface-to-volume ratio shows potential applications in UV-ray shielding, self-cleaning devices, energy conversion and storage. Well dispersed rod-shaped rutile was prepared by hydrolysis of TiCl4 with hydrochloric acid (HCl) solutions and FeCl3 at low temperature. The crystalline form and morphology were characterized by X-ray diffraction (XRD), Raman spectrum and transmission electron microscopy (TEM). The doping of iron was confirmed by X-ray photoelectron spectroscopy (XPS) analysis. A series of experiments were conducted to figure out the effects of reaction conditions on the crystalline form and shape of the powders. The results showed that either change of acids (H2SO4 or HNO3) or varying of cations (NaCl or AlCl3) leaded to a mixed products or pure anatase. A possible mechanism was proposed to explain why the change of minerals or acids would make such a remarkable difference.
Co-reporter:Peng Liu;Chong Gao;Chunchun Han;Hanying Tang;Feng Wang;Yanfen Ding;Shimin Zhang
Polymer International 2015 Volume 64( Issue 8) pp:1053-1059
Publication Date(Web):
DOI:10.1002/pi.4921
Abstract
A nanosilica-immobilized UV absorber (SiO2-APTMS-UVA) was prepared by the following methods: the fumed nanosilica was first modified with an aminosilane coupling agent 3-aminopropyltrimethoxysilane (APTMS) and then reacted with hydroxy-benzoyl chloride. Several measurements confirmed that the UV absorber was chemically immobilized on the surface of the nanosilica. SEM observation showed that SiO2-APTMS-UVA was homogeneously dispersed in the matrix of low density polyethylene (LDPE) and polypropylene (PP). The photo-degradation of the nanocomposites was evaluated by an accelerated aging test. It was found that the SiO2-APTMS-UVA has a great effect on preventing the degradation of LDPE or PP under UV exposure. © 2015 Society of Chemical Industry
Co-reporter:Ping Lei, Feng Wang, Shimin Zhang, Yanfen Ding, Jincai Zhao, and Mingshu Yang
ACS Applied Materials & Interfaces 2014 Volume 6(Issue 4) pp:2370
Publication Date(Web):January 14, 2014
DOI:10.1021/am4046537
Abundant and renewable solar light is an ideal resource for the industrial application of TiO2 photocatalysis in environmental purification. Over the past decades, the pursuit for visible-light photocatalysts with low cost, simple process, and high efficiency remains a challenging task. Here, we report a novel organic–inorganic nanohybrid photocatalyst (conjugation-grafted-TiO2) by chemically grafting conjugated structures onto the surfaces of TiO2 nanoparticles through controlled thermal degradation of the coacervated polymer layer. The interfacial C–O–Ti bonds between TiO2 and conjugated structures can act as the pathway to quickly transfer the excited electrons from conjugated structures to TiO2, therefore contribute to high visible-light photocatalytic efficiency. Our findings provide an economic route to prepare the conjugation-grafted-TiO2 nanohybrid, and develop a routine to improve the photocatalytic efficiency of organic–inorganic hybrid materials through the interfacial interaction.Keywords: conjugation; electron transfer; grafting; nanohybrid; TiO2; visible light;
Co-reporter:Chong Gao, Shimin Zhang, Feng Wang, Bin Wen, Chunchun Han, Yanfen Ding, and Mingshu Yang
ACS Applied Materials & Interfaces 2014 Volume 6(Issue 15) pp:12252
Publication Date(Web):June 27, 2014
DOI:10.1021/am501843s
Acrylonitrile-butadiene-styrene resin (ABS)/graphene nanocomposites were prepared through a facile coagulation method. Because the chemical reduction of graphene oxide was in situ conducted in the presence of ABS at the dispersion stage, the aggregation of the graphene nanosheets was avoided. It was shown by transmission electron microscopy that the graphene nanosheets were selectively located and homogeneously dispersed in the styrene-acrylonitrile (SAN) phase. The electrical conductivity and linear viscoelastic behavior of the nanocomposites were systematically studied. With increasing filler content, graphene networks were established in the SAN phase. Consequently, the nanocomposites underwent a transition from electrical insulator to conductor at a percolation threshold of 0.13 vol %, which is smaller than that of other ABS composites. Such a low percolation threshold results from extreme geometry, selective localization, and homogeneous dispersion of the graphene nanosheets in SAN phase. Similarly, the rheological response of the nanocomposites also showed a transition to solid-like behavior. Due to the thermal reduction of graphene nanosheets and structure improvement of graphene networks, enhanced electrical conductivity of the nanocomposites was obtained after annealing.Keywords: ABS resin; electrical conductivity; graphene; network; rheology; selective localization
Co-reporter:Lin Qi;Yanfen Ding;Quanxiao Dong;Bin Wen;Feng Wang;Shimin Zhang
Journal of Applied Polymer Science 2014 Volume 131( Issue 16) pp:
Publication Date(Web):
DOI:10.1002/app.40601
ABSTRACT
Rutile-type titanium dioxide (TiO2) nanorods were prepared, superficially modified and tested for the protection of polypropylene (PP) from the UVB and UVC irradiations. The silica coating blocked the active sites on the nanorods and the following calcination further reduced the amount of surface hydroxyl groups and thus, made the TiO2 nanorods more efficient against the photodegradation. Compared with spherical TiO2 nanoparticles, the calcined silica-coated TiO2 nanorods demonstrated good photostabilization efficiency due to the excellent shielding effect and the improved dispersion of the nanoparticles in PP matrix. When used in combination with the conventional hindered amine light stabilizer (HALS), CHIMASSORB® 944, the surface modified TiO2 nanorods revealed strong synergistic effect during the photo-oxidation of the PP composites. The capacity of photostabilization was much higher than the combination with the commercial spherical TiO2 nanoparticles and even higher than the typical HALS photostabilization system containing hindered phenol TINUVIN® 328. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40601.
Co-reporter:Lin Qi;Yan-fen Ding;Quan-xiao Dong;Bin Wen
Chinese Journal of Polymer Science 2014 Volume 32( Issue 7) pp:834-843
Publication Date(Web):2014 July
DOI:10.1007/s10118-014-1472-3
Surface modified rutile-type titanium dioxide (CST) nanorods were used as a UV absorber in polypropylene (PP) thick bars in combination with the hindered amine light stabilizer (HALS) Chimassorb® 944 (C944). For all of the tested samples, the photodegradation was mainly limited in the region near the exposed surface, as proved by the carbonyl index and molecular weight. Compared with the typical HALS photostabilization system containing organic hindered phenol UV absorber Tinuvin® 328 (T328), the thickness of photodegradation region for PP/C944/CST was only a quarter to that for PP/C944 and PP/C944/T328, while the rates of reduction in molecular weight and increase in carbonyl index were much lower. Optical microscopic observation showed that the evolution of surface micro-cracks in PP/C944/CST was quite different from that in the other samples, while scanning electronic micrographs revealed that the depth of the micro-cracks in PP/C944/CST was much shorter than that in the others. It is therefore concluded that the protection of CST on PP thick bars is mainly attributed to the outstanding UV-shielding and cracks-blocking abilities.
Co-reporter:Quanxiao Dong, Laurence C. Chow, Tongxin Wang, Stanislav A. Frukhtbeyn, Feng Wang, Mingshu Yang, James W. Mitchell
Colloids and Surfaces A: Physicochemical and Engineering Aspects 2014 Volume 457() pp:256-262
Publication Date(Web):5 September 2014
DOI:10.1016/j.colsurfa.2014.05.047
•A new bioresorbable composite was prepared from PLA and a more basic TTCP filler.•TTCP filler may reduce inflammation by neutralizing the acid degraded from PLA.•AEAPS and PMDA were used to improve the interfacial and mechanical strength.A new bioresorbable polylactide/calcium phosphate composite with improved mechanical strengths and a more basic filler, tetracalcium phosphate (TTCP), was prepared by melt compounding. N-(2-aminoethyl)-3-aminopropyltrimethoxysilane (AEAPS) and pyromellitic dianhydride (PMDA) were used to improve the interfacial adhesion between TTCP and polylactide (PLA). While AEAPS improved the dispersion of TTCP in the matrix, PMDA might react with the terminal hydroxyl group of PLA and the amino group on the surface of AEAPS modified TTCP, which could further enhance the interfacial strength. The tensile strength was improved to 68.4 MPa for the PLA/TTCP–AEAPS composite from 51.5 MPa for the PLA/TTCP composite (20 wt% of TTCP). Dynamic mechanical analysis suggested that there was a 51% improvement in storage modulus compared to that of PLA alone, when PMDA (0.2 wt% of PMDA) was incorporated into the PLA/TTCP–AEAPS composite (5 wt% of TTCP). Using this new bioresorbable PLA composite incorporated with a more basic filler for biomedical application, the inflammation and allergic effect resulted from the degraded acidic product are expected to be reduced.
Co-reporter:Peng Liu;Mingming Liu;Chong Gao;Feng Wang;Yanfen Ding;Bin Wen;Shimin Zhang
Journal of Applied Polymer Science 2013 Volume 130( Issue 2) pp:1301-1307
Publication Date(Web):
DOI:10.1002/app.39318
ABSTRACT
A phosphorous flame retardant (DOPO-MAH) was synthesized through the reaction between of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and maleic anhydride (MAH) and confirmed by FT-IR, 1H NMR, and 31P NMR techniques. The obtained flame retardant was then melt blended with poly(butylene terephthalate) (PBT) to prepare flame retardant PBT/DOPO-MAH composites. The composites were characterized by LOI, UL-94, and mechanical tests as well as scanning electron microscopy, thermogravimetric analysis, and differential scanning calorimetry analysis. On adding 20 wt % DOPO-MAH, LOI increased from 20.9 to 25.7 and the UL-94 V-0 rating was achieved, whereas the tensile and flexural properties were notably improved. Torque-time profile during the melt blending and intrinsic viscosity of the composite indicated that DOPO-MAH acted as both flame retardant and chain extender for the PBT matrix. The results showed that PBT/DOPO-MAH composite is a promising material for its good comprehensive properties. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1301-1307, 2013
Co-reporter:Quanxiao Dong;Mingming Liu;Yanfen Ding;Feng Wang;Chong Gao;Peng Liu;Bin Wen;Shimin Zhang
Polymers for Advanced Technologies 2013 Volume 24( Issue 8) pp:732-739
Publication Date(Web):
DOI:10.1002/pat.3137
The synergistic effect of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) immobilized silica (SiO2-DOPO) nanoparticles with an intumescent flame retardant (IFR) on the flame retardancy of polypropylene (PP) was investigated by UL 94 vertical tests and limiting oxygen index (LOI) measurements. It was found that the PP/IFR composites (25 wt%) achieved the UL94 V0 grade and LOI increased to 32.1 with an incorporation of 1.0 wt% SiO2-DOPO nanoparticles. Based on thermogravimetric analysis, scanning electronic microscopy and rheological analysis, it is speculated that three factors are mainly contributed to the improvement of the flame retardancy. First, the thermal stability of PP/IFR composites was improved by incorporating SiO2-DOPO nanoparticles. Second, the presence of SiO2-DOPO nanoparticles could induce the formation of a continuous char skin layer during combustion. The compact char layer could effectively impede the transport of bubbles and heat. Third, rheological analysis indicated that SiO2-DOPO nanoparticles could increase viscosity of the PP/IFR composites, which was also benefited to increase flame retardancy. Copyright © 2013 John Wiley & Sons, Ltd.
Co-reporter:Quanxiao Dong;Chong Gao;Yanfen Ding;Feng Wang;Bin Wen;Shimin Zhang;Tongxin Wang
Journal of Applied Polymer Science 2012 Volume 123( Issue 2) pp:1085-1093
Publication Date(Web):
DOI:10.1002/app.34574
Abstract
A new flame retardant polycarbonate/magnesium oxide (PC/MgO) nanocomposite, with high flame retardancy was developed by melt compounding. The effect of MgO to the flame retardancy, thermal property, and thermal degradation kinetics were investigated. Limited oxygen index (LOI) test revealed that a little amount of MgO (2 wt %) led to significant enhancement (LOI = 36.8) in flame retardancy. Thermogravimetric analysis results demonstrated that the onset temperature of degradation and temperature of maximum degradation rate decreased in both air and N2 atmosphere. Apparent activation energy was estimated via Flynn–Wall–Ozawa method. Three steps in the thermal degradation kinetics were observed after incorporation of MgO into the matrix and the additive raised activation energies of the composite in the full range except the initial stage. It was interpreted that the flame retardancy of PC was influenced by MgO through the following two aspects: on the one hand, MgO catalyzed the thermal-oxidative degradation and accelerated a thermal protection/mass loss barrier at burning surface; on the other hand, the filler decreased activation energies in the initial step and improved thermal stability in the final period. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Co-reporter:Quanxiao Dong;Yanfen Ding;Bin Wen;Feng Wang;Huicong Dong
Colloid and Polymer Science 2012 Volume 290( Issue 14) pp:1371-1380
Publication Date(Web):2012 September
DOI:10.1007/s00396-012-2631-0
After the surface silylation with 3-methacryloxypropyltrimethoxysilane, silica nanoparticles were further modified by 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO). The immobilization of DOPO on silica nanoparticles was confirmed by Fourier transform infrared spectroscopy, UV–visible spectroscopy, magic angle spinning nuclear magnetic resonance, and thermogravimetric analysis. By incorporating the DOPO-immobilized silica nanoparticles (5 wt%) into polypropylene matrix, the thermal oxidative stability exhibited an improvement of 62 °C for the half weight loss temperature, while that was only 26 °C increment with incorporation of virgin silica nanoparticles (5 wt%). Apparent activation energies of the polymer nanocomposites were estimated via Flynn–Wall–Ozawa method. It was found that the incorporation of DOPO-immobilized silica nanoparticles improved activation energies of the degradation reaction. Based on the results, it was speculated that DOPO-immobilized silica nanoparticles could inhibit the degradation of polypropylene and catalyze the formation of carbonaceous char on the surface. Thus, thermal stability was significantly improved.
Co-reporter:Junhua Zhang ; Frans H. J. Maurer
The Journal of Physical Chemistry C 2011 Volume 115(Issue 21) pp:10431-10441
Publication Date(Web):May 11, 2011
DOI:10.1021/jp201613x
TiO2 nanoparticles were in situ generated in one-dimensional poly(methyl methacrylate) PMMA nanohybrid fibers with excellent dispersion by using electrospinning combined with a sol–gel method followed by a mild hydrothermal treatment that preserves the properties of the polymer to the maximum degree. Detailed information of the preparation method, synthesis route, structure and properties of TiO2/PMMA nanohybrids is revealed. The possible rationale for the uniform formation of TiO2 nanoparticles in the PMMA matrix is discussed with respect to the role of the acid solvent trifluoroacetic acid (TFA) as well as the electrospun fiber structure in the sol–gel and hydrothermal process. The use of TFA in the preparation of electrospun precursor/PMMA solutions induces full hydrolysis of titanium alkoxide. The rapid electrospinning process suppresses the condensation reaction of the precursor. The strong hydrogen bonding interaction between hydrolyzed inorganic precursor and the polymer results in stable precursor/PMMA nanohybrids at ambient conditions. The solid fibrous polymer structure facilitates the generation and homogeneous distribution of nanosized TiO2 particles within the PMMA matrix at hot water conditions, which are ready to be used in biomedical and optical applications.
Co-reporter:Junhua Zhang;Bin Wen;Feng Wang;Yanfen Ding;Shimin Zhang
Journal of Polymer Science Part B: Polymer Physics 2011 Volume 49( Issue 19) pp:1360-1368
Publication Date(Web):
DOI:10.1002/polb.22306
Abstract
Hybrid nanofibers of ZnO precursors/PET were fabricated by electrospinning a nonaqueous poly(ethylene terephthalate) (PET) solution containing zinc acetate dihydrate. Scanning electron microscopy images showed that the as prepared nanofibers had smooth and uniform surfaces, and the diameter was decreased with increasing zinc acetate dihydrate content and reducing PET concentration. After the treatment by a mild process of immersing the fibers in ammonia-ethanol mixtures (pH ≈ 9–11), the surface of the nanofibers became rough during the formation of ZnO nanocrystals in the fibers. High resolution transmission electron microscopy images showed that the mean particle size became smaller with increasing diameter of the polymer fibers and decreasing content of ZnO. Fourier transform infrared spectra confirmed the ZnO formation in the hybrid nanofibers. X-ray diffractometry patterns indicated that ZnO had the Wurtzite structure. The formation and growth of ZnO nanocrystals in the nanofiber matrices was also influenced by the various other parameters, that is, the pH value of the reaction solution, the content of zinc acetate dihydrate within the fibers, the reaction time and temperature. Photoluminescence spectra under excitation at 300 nm revealed a broad and intense ultraviolet emission. The UV-visible diffuse reflectance spectra demonstrated the blue shift in the absorbance curve, which was ascribed to the quantum confinement effects of ZnO nanoparticles in the hybrid materials. These hybrid nanofibers can potentially be used in light emitters, chemical sensors, photo-catalysts and solar cells. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 49: 1360–1368, 2011
Co-reporter:Junhua Zhang, Mingshu Yang, and Frans H. J. Maurer
Macromolecules 2011 Volume 44(Issue 14) pp:5711-5721
Publication Date(Web):June 22, 2011
DOI:10.1021/ma201004b
Positron annihilation lifetime spectroscopy (PALS) has been performed on a series of PMMA nanohybrids containing nanometric TiO2, which were produced by means of different preparation methods, i.e., melt mixing, electrospinning combined with solution mixing, or in-situ sol–gel growth methods, to study the effect of filler content and constituents on the free volume properties. The PMMA nanocomposites containing titania precursor or in-situ-formed TiO2 additives exhibit altered free volume properties compared to adding commercial TiO2 P25 fillers. The orthopositronium (o-Ps) lifetime (τ3) (free volume cavity size) was constant with composition in P25/PMMA nanohybrids due to the absence of interfacial interaction. However, in TiO2 precursor/PMMA composite fibers the free volume cavity size decreased substantially with hydroxyl group concentration and recovered after hydrothermal treatment. Additionally, a strong correlation between the glass transition temperature and the o-Ps lifetime in the nanohybrids was observed. These effects are caused by the hydrogen-bonding interaction between hydroxyl groups in the inorganic phase and carbonyl groups in the PMMA matrix, which concentration is dependent on the hydrothermal treatment, leading to differences in the packing of the polymer chains and a changed polymer segmental flexibility. The results also show a clear linear decrease in the o-Ps yield (I3) with increasing P25 content of the composites. A dominant inhibition effect was observed in the TiO2 precursor/PMMA systems, caused by inhibition of positronium formation by the hydroxyl group in the titania precursor. In addition to the pronounced negative deviations of the o-Ps intensity with the concentration of hydroxyl groups in in-situ TiO2/PMMA nanohybrid fibers, a stronger inhibition efficiency of hydroxyl groups was observed than in the precursor/PMMA nanocomposite fibers.
Co-reporter:Jing Chen, Ming Shu Yang, Shi Min Zhang
Composites Part A: Applied Science and Manufacturing 2011 Volume 42(Issue 5) pp:471-477
Publication Date(Web):May 2011
DOI:10.1016/j.compositesa.2011.01.006
Nanosilica was firstly reacted with the reactive antioxidant, methyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate (AO), via transesterification, to form a nanosilica-immobilized antioxidant, AO-silica. And then it was incorporated into polypropylene (PP) by melt compounding. Fourier transform infrared spectroscopy combined with the other characterization methods elucidated that the reactive antioxidant was chemically immobilized onto the nanosilica surface. SEM observation showed that the nanosilica-immobilized antioxidant was homogeneously dispersed into the matrix of PP. It has been reported that the antioxidative efficiency of AO-silica was superior to the corresponding low molecular counterpart (AO), based on the measurement of the oxidation induction time (OIT) of the PP/AO-silica and the PP/AO compounds containing equivalent antioxidant component. By paying attention to the changes of carbonyl absorption at different UV exposure times, it was observed that the UV aging-resistance ability of PP/nanosilica-immobilized antioxidant was much higher than that of PP/neat nanosilica compound during the long-time accelerated photo aging.
Co-reporter:Feng Wang;DongMin Zhang;YanFen Ding;LiXin Zhang
Science Bulletin 2011 Volume 56( Issue 1) pp:14-17
Publication Date(Web):2011 January
DOI:10.1007/s11434-010-4174-4
The pipeline transportation of waxy crude oil is a problem both at home and abroad. In this paper, a novel nanohybrid pour-point depressant (PPD) was used to decrease the pour point and viscosity of waxy crude oil. The pour point and apparent viscosity of waxy crude oil was decreased significantly upon addition of the nanohybrid PPD, and the long-term stability of the nanohybrid PPD was superior to that of a conventional ethylene-vinyl acetate copolymer PPD. Polarized optical microscopy and X-ray diffraction were used to study the effect of the nanohybrid PPD on the crystallization of crude oil. Addition of the nanohybrid PPD reduced the amount of wax crystals, prevented their aggregation, and reduced the temperature at which the crude oil started to crystallize. The significant effect of this nanohybrid PPD on the pour point and viscosity depressing of crude oil is of great importance for facilitating the safe, efficient and energy-minimized transportation of waxy crude oil.
Co-reporter:Xinfeng Xu;Yanfen Ding;Feng Wang;Bin Wen;Junhua Zhang;Shimin Zhang
Polymer Composites 2010 Volume 31( Issue 5) pp:825-834
Publication Date(Web):
DOI:10.1002/pc.20865
Abstract
An alkylammonium intercalated montmorillonite (A-MMT) was modified by edge grafting with 3-glycidoxypropyltrimethoxysilane. In comparison with poly(ethylene terephthalate) (PET)/A-MMT, the resultant grafted clay, S-A-MMT, exhibited improved miscibility with PET matrix and revealed better dispersion state in the melting compounded PET/S-A-MMT nanocomposites. As a result, the PET/S-A-MMT nanocomposite had slower degradation rate owing to the enhanced clay barrier effect. Meanwhile, the nanocomposite exhibited lower degradation onset temperature under nitrogen because of the clay catalysis effect, which can be explained by the decreasing degradation reaction energy calculated from Coats–Redfern method of degradation kinetics. In the other hand, nanocomposite with better clay dispersion state exhibited increasing thermal oxidative stability due to clay barrier effect of hindering oxygen to diffuse in, which accorded with the continuous and compact char surface formed during polymer degradation. The clay catalysis and barrier effect of silicate layers were presented directly in isothermal oxidative TGA experiment. Furthermore, the mechanical and crystallization properties of PET/clay nanocomposites were investigated as well. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers
Co-reporter:Xinfeng Xu, Yanfen Ding, Zhongzhong Qian, Feng Wang, Bin Wen, Hu Zhou, Shimin Zhang, Mingshu Yang
Polymer Degradation and Stability 2009 Volume 94(Issue 1) pp:113-123
Publication Date(Web):January 2009
DOI:10.1016/j.polymdegradstab.2008.09.009
Organoclays with various contents of hydroxyl groups and absorbed ammonium were prepared and compounded with poly(ethylene terephthalate) (PET), forming PET/clay nanocomposites via melt extrusion. Dilute solution viscosity techniques were used to evaluate the level of molecular weight of PET/clay nanocomposites. Actually, a significant reduction in PET molecular weight was observed. The level of degradation depended on both the clay structure and surfactant chemistry in organoclays. The composites, based on clay with larger amount of hydroxyl groups on the edge of clay platelets, experienced much more degradation, because the hydroxyl groups acted as Brønsted acidic sites to accelerate polymer degradation. Furthermore, organoclays with different amounts of absorbed ammonium led to different extents of polymer degradation, depending upon the acidic sites produced by the Hofmann elimination reaction of ammonium. In addition, the composite with better clay dispersion state, which was considered as an increasing amount of clay surface and ammonium exposed to the PET matrix, experienced polymer degradation more seriously. To compensate for polymer degradation during melt extrusion, pyromellitic dianhydride (PMDA) was used as chain extender to increase the intrinsic viscosity of polymer matrix; more importantly, the addition of PMDA had little influence on the clay exfoliation state in PET/clay nanocomposites.
Co-reporter:Xiangfu Meng;Haitao Wang;Zhongzhong Qian;Xiaowei Gao;Qingfeng Yi;Shimin Zhang
Polymer Composites 2009 Volume 30( Issue 5) pp:543-549
Publication Date(Web):
DOI:10.1002/pc.20584
Abstract
Photodegradable polypropylene (PP) composites were prepared via melting blending using PP and titanium dioxide (TiO2) immobilized organically modified montmorillonite (organoclay). TiO2 immobilized organoclay (TiO2-OMT) was synthesized by immobilizing anatase TiO2 nanoparticles on organically modified clay via sol–gel method. The structure and morphology of TiO2-OMT were characterized by XRD and scanning electron microscope (SEM), which showed that anatase TiO2 nanoparticles with the size range of 8–12 nm were uniformly immobilized on the surface of organoclay layers. Diffuse reflection UV–vis spectra revealed TiO2-OMT had similar absorbance characters to that of commercial photocatalyst, Degussa P25. The solid-phase photocatalytic degradation of PP/TiO2-OMT composites was investigated by FTIR, DSC, GPC and SEM. The results indicated that TiO2-OMT enhanced the photodegradation rate of PP under UV irradiation. This was due to that immobilization of TiO2 nanoparticles on organoclay effectively avoided the formation of aggregation, and thereby increased the interface between PP and TiO2 nanoparticles. After 300 h irradiation, the average molecular weight was reduced by two orders of magnitude. This work presented a promising method for preparation of environment-friendly polymer nanocomposites. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers.
Co-reporter:Zhongzhong Qian;Hu Zhou;Xinfeng Xu;Yanfen Ding;Shimin Zhang
Polymer Composites 2009 Volume 30( Issue 9) pp:1234-1242
Publication Date(Web):
DOI:10.1002/pc.20683
Abstract
The CTAB ammonium intercalated montmorillonite clay, CMT, was modified by an alkylsilane, Dodecyltrimethoxylsilane, to improve the miscibility of organoclays with PE matrix, involving the grafting reaction between the silane and silanol groups on the edge of clay. The silane modified clays (DMT) exhibited improved thermal stability due to the replacement of the physically adsorbed ammonium by the covalently bonded silane. The clays were melt compounded with polyethylene. Compared with the composite of PE/CMT, the clay dispersion state was improved, and a unique orientation of the clay layered was observed in PE/DMT nanocomposites, which was confirmed by XRD and TEM studies. The dispersion state, orientation degree of clay and, as a result, the mechanical and thermal properties of the nanocomposites were enhanced with the increasing amount of the grafted silane, indicating that the edge grafting of silane played a crucial role in controlling the structure and properties of nanocomposites. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers
Co-reporter:Xiangfu Meng, Nan Luo, Shengli Cao, Shimin Zhang, Mingshu Yang, Xiao Hu
Materials Letters 2009 Volume 63(Issue 16) pp:1401-1403
Publication Date(Web):30 June 2009
DOI:10.1016/j.matlet.2009.03.023
In-situ growth of titania nanoparticles in poly (ethylene terephthalate) (PET) nanofibers has been successfully achieved by combining sol–gel method and electrospinning process. Titania precursor, tetra-n-butyl titanate (TBT), was firstly hydrolyzed in trifluoroacetic acid (TFA), and then blend with a solution of PET in mixture of trifluoroacetic acid/dichloromethane (TFA/DCM) to form a homogeneous solution for electrospinning. Titania nanoparticles in-situ generated in the electrospun nanofibers via a hydrothermal treatment process at 70 °C–90 °C. The morphology and crystallinity of PET/TiO2 hybrid nanofibers were investigated using TEM and DSC. The results showed that titania nanoparticles of anatase phase with an average diameter of about 10 nm in-situ generated both inside and on the surface of PET electrospun nanofibers. The reversible networks formed between titania nanoparticles and PET macromolecular chains led to considerable decrease of PET crystallinity.
Co-reporter:Xiaowei Gao, Xiangfu Meng, Haitao Wang, Bin Wen, Yanfen Ding, Shimin Zhang, Mingshu Yang
Polymer Degradation and Stability 2008 Volume 93(Issue 8) pp:1467-1471
Publication Date(Web):August 2008
DOI:10.1016/j.polymdegradstab.2008.05.009
A nanosilica-immobilized antioxidant was prepared and incorporated into polypropylene (PP) by melt compounding. It has been found that the antioxidant efficiency of the nanosilica-immobilized antioxidant was superior to the corresponding low molecular counterpart (AO), based on the measurement of the oxidation induction time (OIT) of PP/nanosilica-immobilized antioxidant and PP/AO compounds containing an equivalent antioxidant component. By paying attention to the changes of carbonyl absorption and tensile strength of PP compounds with thermal oven aging time, it was observed that the thermal oxidative stability of PP/nanosilica-immobilized antioxidant was much higher than that of PP/AO compound during the long-term accelerated thermal aging.
Co-reporter:Feng Wang, Xiangfu Meng, Xinfeng Xu, Bin Wen, Zhongzhong Qian, Xiaowei Gao, Yanfen Ding, Shimin Zhang, Mingshu Yang
Polymer Degradation and Stability 2008 Volume 93(Issue 8) pp:1397-1404
Publication Date(Web):August 2008
DOI:10.1016/j.polymdegradstab.2008.05.026
The blends of poly(ethylene terephthalate) (PET) and poly(butylene terephthalate) (PBT) undergo transesterification reactions between PET and PBT during melt processing. In this research, PET/PBT transesterification has been investigated in the presence of nano-fillers, including pure SiO2 and silane-coupling-agent-modified SiO2. The results show that the incorporation of SiO2 nanoparticles inhibits PET/PBT transesterification, and the influence of pure SiO2 is higher than modified SiO2. The inhibition of SiO2 on transesterification is explained by the fact that the hydroxyl end groups of PET and PBT react with the surface hydroxyl groups of SiO2 before transesterification due to the high activity of surface hydroxyl groups of SiO2, and the reduction of hydroxyl end groups of PET and PBT leads to the inhibition of transesterification between PET and PBT. This has been demonstrated by the experimental data of TGA, FTIR, and XPS. And the reactivity of hydroxyl end groups of PBT is higher than that of PET.
Co-reporter:Haitao Wang, Xiangfu Meng, Bin Wen, Xiaowei Gao, Shimin Zhang, Mingshu Yang
Materials Letters 2008 Volume 62(21–22) pp:3745-3747
Publication Date(Web):15 August 2008
DOI:10.1016/j.matlet.2008.04.045
Melamine-formaldehyde resin microencapsulated red phosphorus was successfully prepared for the first time using montmorillonite as a stabilizer. The microencapsulated red phosphorus was characterized with FTIR, XPS and SEM. Meanwhile, its water absorption, ignition point and particle size distribution were also determined. Particle size analysis showed that montmorillonite could function as an effective stabilizer during the microencapsulation process of red phosphorus, and montmorillonite had the similar effects of the common surfactant sodium dodecyl sulfate (SDS). Moreover, the obtained montmorillonite stabilized microcapsules also exhibited lower water absorption and higher ignition point compared with the common red phosphorus microcapsules stabilized with surfactant SDS.
Co-reporter:Guangjun Hu;Xiyan Feng;Shimin Zhang
Journal of Applied Polymer Science 2008 Volume 108( Issue 6) pp:4080-4089
Publication Date(Web):
DOI:10.1002/app.28048
Abstract
Crystallization behavior of poly(ethylene terephthalate)/multiwalled carbon nanotubes (PET/MWNTs) composites have been investigated under isothermal conditions and in comparison with the conventional nucleating agents, sodium benzoate, and micrometric carbon/glass fibers. In the PET/MWNTs composites, MWNTs promote the crystallization of PET as a heterogeneous nucleating agent, and the nucleation efficiency is greatly enhanced when MWNTs was homogeneously dispersed in PET matrix. In comparison with pure PET, spherulites size of PET/MWNTs composites is significantly reduced, and the shape becomes quite irregular. TEM images indicate that MWNTs bundles locate in the center of spherulites of PET and act as nuclei. Fold surface free energy during nucleation process for MWNTs nucleated PET is just half of pure PET, suggesting that MWNTs are efficient nucleating agents for PET. The sequence of nucleating ability of is given as follows: sodium benzoate>MWNTs>talc>carbon fibers≈glass fibers. The nucleation in the presence of sodium benzoate is a chemical nucleation process that may cause severe degradation of PET, but MWNTs nucleate PET through “particle effect,” which does not affect the molecular weight of PET. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Co-reporter:Hu Zhou;Shimin Zhang
Journal of Applied Polymer Science 2008 Volume 108( Issue 6) pp:3822-3827
Publication Date(Web):
DOI:10.1002/app.27984
Abstract
Nylon 6/clay nanocomposites (NCNs) of different clay loadings are prepared by melt compounding. The effects of clay loading and dispersion on the thermal conductivity of NCNs are investigated using XRD, TEM, DSC, and POM. The results show that the thermal conductivity of the exfoliated NCNs decreases with an increase of clay content; but the thermal conductivity of the intercalated NCNs does not decrease, indeed, it increase markedly at high clay content. Such results observed in the exfoliated NCNs are opposite to the expectation of the classic Maxwell thermal conduction model. The further investigations indicate that such decrease observed in the exfoliated NCNs is due mainly to the exfoliation of clay layers. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Co-reporter:Xiangfu Meng;Zhongzhong Qian;Haitao Wang
Journal of Sol-Gel Science and Technology 2008 Volume 46( Issue 2) pp:195-200
Publication Date(Web):2008 May
DOI:10.1007/s10971-008-1677-4
In this study, SiO2/TiO2–organoclay hybrids with high adsorption capability and high photocatalytic activity were synthesized by immobilizing mixed silica and titanium dioxide nanoparticles on organically modified clay via a hydrothermal sol–gel method. Addition of negatively charged silica particles enhanced the uniform dispersion of titanium dioxide nanoparticles on organoclay layers by decreasing the system tension, which resulted in high photocatalytic activity of SiO2/TiO2–organoclay hybrids. The high adsorption capability endowed by organically modified clay enriched the organic compounds around the photoactive sites, and thus greatly improved the photodegradation efficiency. Combining the high adsorption capability of organoclay with the high photocatalytic activity of TiO2 nanoparticles, SiO2/TiO2–organoclay hybrids were promising and cost-effective photocatalysts in removal of pollutants from wastewater.
Co-reporter:Yanfen Ding;Shimin Zhang;Hu Zhou;Zhongzhong Qian;Xiangfu Meng
Journal of Applied Polymer Science 2007 Volume 106(Issue 3) pp:1751-1756
Publication Date(Web):17 JUL 2007
DOI:10.1002/app.26818
In this paper, short carbon-fiber-reinforced nylon 6/clay nanocomposites are prepared via melt compounding, and fiber breakage and dispersion during processing are studied. The influences of clay and processing conditions on fiber breakage and dispersion are taken into consideration. It is found that the presence of organoclay can improve fiber dispersion, which is due to dispersion at the nanoscale of exfoliated clay sheets with large aspect ratio. The bimodal distribution of fiber length is observed in fiber-reinforced nanocomposites, which is similar to that in conventional fiber-reinforced composites. The improvement of fiber breakage at moderate organoclay loadings is also observed, which is ascribed to the rheological and lubricating effects induced by organoclay. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Co-reporter:Quansheng Su;Meng Feng;Shimin Zhang;Jianming Jiang
Polymer International 2007 Volume 56(Issue 1) pp:
Publication Date(Web):15 AUG 2006
DOI:10.1002/pi.2109
The melt blending of polypropylene-blend-polyamide 6-blend-organoclay (PP/PA6/organoclay) systems has been investigated using an internal mixer without any traditional compatibilizer. In the presence of organoclay, the melting of PA6 phase is accelerated and the dimension of the dispersed phase in the matrix is reduced. Transmission electron microscopy results reveal clay-rich interface zones formed between the PA6 dispersed phase and the PP matrix in the PP/PA6/organoclay system. An interface blending approach has been designed to investigate the interface zones between the immiscible polymers, and the interface zones have been characterized by Fourier transform infrared and X-ray photoelectron spectroscopy. In the presence of the organoclay, the PA6 component in interface zones is stable even after etching extraction with formic acid, suggesting a strong interaction takes place among PP, PA6 and the organoclay. Such clay-rich interface zones act as a compatibilizer for the two immiscible polymers, resulting in a better dispersion of PA6 phase in PP matrix. Copyright © 2006 Society of Chemical Industry
Co-reporter:Guangjun Hu;Xiangfu Meng;Xiyan Feng;Yanfen Ding
Journal of Materials Science 2007 Volume 42( Issue 17) pp:7162-7170
Publication Date(Web):2007 September
DOI:10.1007/s10853-007-1609-7
In the present work, we report the preparation and photocatalytic properties of hybrid nanofibers/mats of anatase TiO2 nanoparticles and multi-walled carbon nanotubes (MWNTs) using combined sol–gel and electrospinning techniques. Poly(vinyl pyrrolidone) is used as a base polymer in the electrospinning suspension to assist the formation of nanofibers and subsequently removed by calcination. The hybrid nanofibers are characterized using XRD, Raman spectra, FT-IR, XPS, SEM, TEM and N2 adsorption measurements. The results show that MWNTs are encapsulated by in-situ formed anatase TiO2 nanoparticles, with chemical bonding C–O–Ti between anatase TiO2 nanoparticles and MWNTs. Hybrid nanofibrous mats with moderate content of MWNTs (mass ratio TiO2:MWNTs = 100:20) exhibit enhanced adsorption ability and excellent photocatalytic activity. The composition, diameter and morphology of hybrid nanofibers can be tuned by varying sol–gel formulation, electrospinning parameter and post-treatment condition. TiO2/MWNTs hybrid nanofiber and mats have promising applications in water purification and solar cell areas.
Co-reporter:Chungui Zhao, Huaili Qin, Fangling Gong, Meng Feng, Shimin Zhang, Mingshu Yang
Polymer Degradation and Stability 2005 Volume 87(Issue 1) pp:183-189
Publication Date(Web):January 2005
DOI:10.1016/j.polymdegradstab.2004.08.005
Polyethylene/clay composites were prepared by melt compounding polyethylene and montmorillonite clay organically modified with different intercalating agents. Wide-angle X-ray diffraction (WAXD) and transmission electron microscopy (TEM) revealed that PE/clay nanocomposites formed when using a reactive intercalating agent, while only conventional microcomposites were obtained from the common alkylammonium intercalated clay. Mechanical testing indicated that the reinforcement in the nanocomposites was more effective than that in their conventional counterparts. The thermal stability and flammability of the PE/clay nanocomposites were measured by thermogravimetric analysis (TGA) and cone calorimetry. By adding only 2 phr organoclay, the peak heat release rate of the nanocomposite was reduced by 54%. Further studies indicated that the improvement of flammability is due to the formation of a clay-enriched protective char during combustion.
Co-reporter:Shimin Zhang;Huaili Qin;Chungui Zhao
Journal of Polymer Science Part B: Polymer Physics 2005 Volume 43(Issue 24) pp:3713-3719
Publication Date(Web):3 NOV 2005
DOI:10.1002/polb.20668
The thermal degradation kinetics of polypropylene/clay microcomposites and nanocomposites were studied by thermogravimetric analysis. In comparison with pure polypropylene, the reaction order of the degradation of the composites became zero-order, and the activation energy increased dramatically. The zero-order kinetics were associated with the acidic sites (H+) created on the clay layers, whereas the increase in the activation energy was coupled with the shielding effect of clay. The kinetic analysis could provide additional mechanistic clues concerning the thermal stability and flammability of polymer/clay nanocomposites. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 3713–3719, 2005
Co-reporter:Fangling Gong, Meng Feng, Chungui Zhao, Shimin Zhang, Mingshu Yang
Polymer Testing 2004 Volume 23(Issue 7) pp:847-853
Publication Date(Web):October 2004
DOI:10.1016/j.polymertesting.2004.02.004
Poly(vinyl chloride)/montmorillonite (PVC/MMT) nanocomposites were synthesized via in situ intercalative polymerization and their microstructure, particle characteristics and mechanical properties were investigated. The montmorillonite layers were almost exfoliated into nanoscale layers and an exfoliated nanostructure was obtained. The mean particle size of the nanocomposites decreased and the degree of porosity of the particles increased with increasing organic modified montmorillonite (OMMT) content. The nanocomposites exhibited higher cold plasticizer absorption (CPA) and slightly greater fluid plasticity in comparison with pure PVC. The addition of OMMT into PVC matrix improved the production process and the mechanical properties of the composite resin.
Co-reporter:Xiyan Feng, Guangjun Hu, Xiangfu Meng, Yanfen Ding, Shimin Zhang, Mingshu Yang
Applied Clay Science (August 2009) Volume 45(Issue 4) pp:239-243
Publication Date(Web):August 2009
DOI:10.1016/j.clay.2009.06.016
Co-reporter:Hanying Tang, Peng Liu, Ming Lu, Yanfen Ding, Feng Wang, Chong Gao, Shimin Zhang, Mingshu Yang
Polymer (10 March 2017) Volume 112() pp:
Publication Date(Web):10 March 2017
DOI:10.1016/j.polymer.2017.02.029
•Antioxidant immobilized on the surface of co-condensed nanosilica (SN-NH2).•The nano-antioxidant (SN-NH2-AO) exhibited good thermal stability.•SN-NH2-AO improved significantly the thermal-oxidative stability of polypropylene.•SN-NH2-AO exhibited excellent anti-extraction property.Antioxidant in form of hindered phenol structure is commonly used to prolong the service life of polymer, while the low molecule antioxidant has defect for its low thermal stability and physical loss. Herein, the feasibility of using co-condensed silica immobilized antioxidant (denoted as SN-NH2-AO) to improve the thermal-oxidative stability of polypropylene (PP) was evaluated. Firstly, SN-NH2-AO was prepared by immobilization of 3,5-di-tert-butyl-4-hydroxyphenylpropionic acid (AO) on the surface of co-condensed silica (SN-NH2) which was synthesized by co-hydrolysis and condensation of tetraethoxysilane and aminopropyltriethoxysilane. Compared with AO, SN-NH2-AO exhibited higher thermal stability. Further, SN-NH2-AO was incorporated into PP by melt blending. The incorporation of SN-NH2-AO could not only disperse well in PP matrix but also improve the thermal-oxidative stability of PP distinctly. It was found that although the anti-oxidative efficiency of SN-NH2-AO was slightly inferior to AO, SN-NH2-AO exhibited superiority on anti-extraction property.Download high-res image (253KB)Download full-size image
Co-reporter:Chunchun Han, Feng Wang, Chong Gao, Peng Liu, Yanfen Ding, Shimin Zhang and Mingshu Yang
Journal of Materials Chemistry A 2015 - vol. 3(Issue 19) pp:NaN5072-5072
Publication Date(Web):2015/04/27
DOI:10.1039/C4TC02880E
It is known that ultraviolet (UV) radiation is harmful to human health and affects the long-term stability of many organic materials. It has recently been discovered that blue radiation also poses a danger. In this study, epoxy–ZnO/CdS (EP–ZC) nanocomposites capable of shielding both UV and blue radiation were developed. First, ZnO/CdS nanoparticles were synthesized through the growth of CdS on prefabricated ZnO quantum dots (ZnO QDs). In contrast to ZnO QDs, which only absorb a portion of UV light, the ZnO/CdS nanoparticles exhibited strong absorption over the wavelength region extending from UV light to blue light. Further, their absorption-band range could be controlled by adjusting the Zn/Cd molar ratio. In situ polymerization was employed to prepare the EP–ZC nanocomposites, which were highly transparent at wavelength greater than 500 nm. It was found that the EP–ZC nanocomposites exhibited strong UV-shielding capability and could almost completely block UV light between 200–400 nm as well as more than 80% of the blue light between 400–450 nm when they contained 0.3 wt% ZnO/CdS nanoparticles. Finally, their optical transparency to visible light in the region beyond blue light was the same as that of pure epoxy due to the uniform dispersion of nanoparticles.
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