Co-reporter:Yi Ye;Ming Tian;Zhongjie Du;Jianguo Mi
Langmuir January 12, 2016 Volume 32(Issue 1) pp:230-238
Publication Date(Web):2017-2-22
DOI:10.1021/acs.langmuir.5b02966
Fluorinated polyhedral oligomeric silsesquioxane (F-POSS) nanoparticles have been widely used to enhance the hydrophobicity or oleophobicity of polymer films via constructing the specific micro/nanoscale roughness. In this work, we study the oleophobicity of pure and F-POSS-decorated poly(vinylidene fluoride) (PVDF) and poly(methyl methacrylate) (PMMA) films using a dynamic density functional theory approach. The role of nanoparticle size and coverage and the chemical features of F-POSS and the polymer film in the wetting behavior of diiodomethane droplets has been integrated to the remaining ratio of surface potential to quantitatively characterize the corner effect. It is shown that, on the basis of universal force field parameters, the theoretically predicted contact angles are in general agreement with the available experimental data.
Co-reporter:Jingxin Zhang, Zhongjie Du, Wei Zou, Hangquan Li, Chen Zhang
Composites Science and Technology 2017 Volume 148(Volume 148) pp:
Publication Date(Web):18 August 2017
DOI:10.1016/j.compscitech.2017.05.008
A magnesium oxide (MgO) nanoparticles-decorated carbon fiber hybrid (CFMgO) were designed and fabricated as thermal conductive but electric insulating filler for polymer matrix. Carbon fibers (CF) and MgO nanoparticles were firstly treated by the coupling agents with amine groups and epoxy groups, respectively. Then CFMgO was constructed through grafting the nanoparticles onto the surface of the fiber. It was expected that the thermal conductivity of CF would be enhanced but its electrical conductivity would be inhibited by the coating of MgO nanoparticles. The chemical structure and morphology of CFMgO were investigated using Fourier transform infrared spectrometer (FT-IR), X-ray photoelectron spectroscopy (XPS), and scanning electron microscope (SEM). Finally, the hybrid filler was introduced into Nylon 6. The strong interfacial interaction between the filler and matrix was exhibited, attributed to the existence of the coupling agents and the rough surface of nanoparticles-decorated CF. The highest thermal conductivity reached 0.748 W/m·K at 20 wt % addition of CFMgO. Meanwhile, the insulation of the composite appeared at higher than 10 wt% addition of the hybrid filler. Furthermore, connected by MgO nanoparticles, less CF was necessary for the construction of heat conduction channel, and lower value of percolation threshold was achieved.
Co-reporter:Yaqi Hou, Zhongjie Du, Chen Zhang, Ming Tian, and Jianguo Mi
The Journal of Physical Chemistry C 2017 Volume 121(Issue 5) pp:
Publication Date(Web):January 17, 2017
DOI:10.1021/acs.jpcc.6b11552
Under the depletion effect of poly(acrylic acid) chains, CdSe nanoparticles coated with oleic acid ligand aggregated into clusters and self-assembled into an ordered two-dimensional hexagon-shaped array on the surface of a carbon film. Such behavior was also reproduced via dynamic density functional theory. Given the same condition, the aggregation enhancement of nanoparticles on the substrate and the ratio of hexagonal side length to vertex size in a crystal cell are similar in both experimental and theoretical sections, suggesting a reasonable interpretation of the mechanism of the disorder-to-order transition. Thereafter, the theoretical predictions reveal the range of spontaneous self-assembly, which can be directed, enhanced, or controlled by changing either nanoparticle size or interactions among nanoparticles, poly(acrylic acid), and substrate.
Co-reporter:Weixia Yang, Wei Zou, Zhongjie Du, Hangquan Li, Chen Zhang
Composites Science and Technology 2016 Volume 123() pp:106-114
Publication Date(Web):8 February 2016
DOI:10.1016/j.compscitech.2015.12.009
Improved conductive polystyrene (PS)-based nanocomposite filled with ultralow addition of multi-walled carbon nanotubes (MWCNTs) were fabricated by concentrated emulsion polymerization. First, the foam structure was constructed to compress MWCNTs into a thin polymer skeleton and enhance the electrical conductivity of the nanocomposite. Second, a polyelectrolyte poly (3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) was introduced onto MWCNTs to reduce the noncontact resistivity within the inter-tube junctions. The effect of porous morphology, the loading phase and content of MWCNTs, and the synergetic effect of MWCNTs and PEDOT:PSS on the electrical conductivity of the nanocomposites were investigated. It was found that the foam structure of nanocomposite with a specific location of conductive fillers can strongly reduce the percolation threshold. In addition, the conductivities of the nanocomposites could be controlled by the porous structure. As a result, the percolation threshold of 0.3 wt% PEDOT:PSS/MWCNTs to PS matrix was achieved, and the highest conductivity was obtained from the foam structure with the thinnest pore wall and the appropriate ratio of PEDOT:PSS/MWCNTs.
Co-reporter:Xiaoqian Zhang, Zhongjie Du, Wei Zou, Hangquan Li, Chen Zhang, Shuxin Li and Wenli Guo
RSC Advances 2015 vol. 5(Issue 81) pp:65890-65896
Publication Date(Web):27 Jul 2015
DOI:10.1039/C5RA12072A
Porous elastic and pressure-sensitive conductive polyurethane (PU) monoliths were synthesized by concentrated emulsion templating. A toluene solution containing tolylene diisocyanat (TDI), castor oil, and a surfactant was used as the continuous phase of the concentrated emulsion, and deionized water was used as the dispersed phase. In order to make the monolith conductive, acid-treated multi-walled carbon nanotubes (MWCNTs) were introduced into it, which were distributed in both phases spontaneously. After the continuous phase of the concentrated emulsion was cured, toluene and water were removed, and a highly porous elastic monolith was obtained. The MWCNTs in the continuous phase were embedded in the bulk PU matrix forming a conductive network and those previously in the dispersed phase were precipitated on the surface of the pore walls. It was the contact extent of the MWCNTs on the pore walls that rendered the monolith with pressure-sensitive conductivity. A compression strain of about 40% could cause a reduction in resistance by two orders of magnitude.
Co-reporter:Jiaxi Han, Zhongjie Du, Wei Zou, Hangquan Li, and Chen Zhang
Industrial & Engineering Chemistry Research 2015 Volume 54(Issue 31) pp:7623-7631
Publication Date(Web):June 29, 2015
DOI:10.1021/acs.iecr.5b01305
This work focuses on developing the adsorbent for carbon dioxide (CO2) capture from high-humidity flue gas by loading moisture-responsive polyethylenimine (PEI) hydrogel interface layer in porous polymer matrix. The chemical structure and porous morphology of the porous adsorbents are characterized. The CO2 adsorption capacity and adsorption thermodynamics are studied. Also, the factors that affect the adsorption capacity including different molecular weight of PEI, loading weight and cross-linking degree of hydrogel, and moisture are investigated. The experimental results show that the porous polymer coated with PEI hydrogel exhibits a much higher adsorption capacity for CO2 and keep a high CO2–N2 selectivity by effective utilization of moisture. The CO2 adsorption capacity as high as 4.85 mmol CO2/g of adsorbent is obtained at 40 °C, with 1,4-butanediol diacrylate (BDA)/PEI ratio of 0.25. Moreover, the formation of three-dimensional cross-linked network in hydrogel shows good regeneration stability.
Co-reporter:Xiaoqian Zhang, Wei Zou, Zhongjie Du, Hangquan Li, Shuxin Li, Minjun Liu, Chen Zhang, Wenli Guo
Materials Chemistry and Physics 2015 Volume 164() pp:78-84
Publication Date(Web):15 August 2015
DOI:10.1016/j.matchemphys.2015.08.025
•Concentrated emulsion template was applied to fabricate PU foam.•The PU foam with an average pore size and an open-cell structure was achieved.•A strengthened interface was important for the stability of concentrated emulsion.•Colloidal silica on interface could improve the stability of concentrated emulsion.•The control on the morphology of porous PU was investigated.A method for preparing porous polyurethane (PU) monoliths through a step polymerization in concentrated emulsion template was proposed. The concentrated emulsion was constructed by using tolylene diisocyanate (TDI), butylenes glycol and a surfactant as the continuous phase, and deionized water as the dispersed phase. Polyglycerol polyricinoleate (PGPR) was selected as the surfactant because it was an amphiphilic oligomer containing reactive hydroxyl groups. It could react with TDI firstly and thus built up a solid interface to maintain the stability of the concentrated emulsion. As a result, polyurethane porous monolith was obtained by the curing reaction between TDI and –OH containing species and thereafter the removal of water phase. When colloidal silica particles were introduced into aqueous phase, a more uniform and finer porous structure could be achieved from the more strengthened interface. The effects of the composition, the surfactant, the volume fraction of dispersed phase, and the content of colloidal silica on the morphology of porous PU were investigated.
Co-reporter:Gaiping Guo;Zhongjie Du;Wei Zou;Aimin Xiang;Hangquan Li
Journal of Applied Polymer Science 2015 Volume 132( Issue 28) pp:
Publication Date(Web):
DOI:10.1002/app.42221
ABSTRACT
Phthalic anhydride modified soy protein (PAS)/glycerol plasticized soy protein (GPS) composite films were fabricated by using extrusion and compression-molding. Modified with phthalic anhydride, the soy protein lost its thermoplastic ability and was used as a filler to reinforce the GPS matrix. Fourier transform infrared spectra, optical transmittance, scanning electron microscope, mechanical tests, water resistance tests, as well as thermo-gravimetric analysis were carried out to investigate the structure and properties of PAS and the plastic composites. The similar chemical structure of PAS and GPS led to compatibility of the two components resulting in high transparency and enhanced tensile properties of the composites. The water resistance of GPS was also improved by the incorporation of PAS. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42221.
Co-reporter:Chunchuang Li, Zhongjie Du, Wei Zou, Hangquan Li, Chen Zhang
Reactive and Functional Polymers 2015 Volume 88() pp:24-30
Publication Date(Web):March 2015
DOI:10.1016/j.reactfunctpolym.2015.02.001
The polymer foam coated with zero-valent copper (Cu0) was designed and prepared for the removal of hexavalent chromium (Cr(VI)) in water. Firstly, porous poly(tert-butyl acrylate) was fabricated by concentrated emulsion polymerization and then acrylic acid groups were generated on the surface of foam by hydrolysis reaction. Secondly, with the help of the large amount reactive carboxylic acid groups, polyethyleneimine (PEI) were chemically grafted onto the surface by the reaction between amine group and acrylic acid group. Finally, zero-valent copper was reduced by sodium borohydride (NaBH4) and coated on the surface of polymer foam. Thus the copper functionalized porous adsorbent (Cu0–PEI–PAA) was constructed, and then applied for removing Cr(VI) from aqueous solution. The removal mechanism of Cr(VI) involved redox reaction by zero-valent copper and adsorption by amine groups, simultaneously. As a result, 99.5% of Cr(VI) could be removed within 2 h, and the maximum removal capacity for Cr(VI) of Cu0–PEI(1800)–PAA was 9.16 mg/g. Furthermore, the effect of initial concentration of Cr(VI), pH value, and temperature on the Cr(VI) removal was investigated. Therefore, the as-prepared zero-valent copper-loaded polymer foam could be an efficient and promising remediation material to remove Cr(VI) from wastewater.
Co-reporter:Yang Wang, Xiangdong Wang, Zhongjie Du, Chen Zhang, Ming Tian, and Jianguo Mi
Langmuir 2015 Volume 31(Issue 8) pp:2342-2350
Publication Date(Web):February 5, 2015
DOI:10.1021/la505035k
The wettability of critical droplets on microscale geometric rough surfaces has been investigated using a density functional theory approach. In order to analyze the effect of roughness on nucleation free-energy barriers, the local density fluctuations at liquid–solid interfaces induced by the multi-interactions of a corner substrate are presented to interpret the interfacial free-energy variations, and the vapor–liquid–solid contact line tensions are derived from the contact angles of nuclei to account for the three-phase contact energies. The corresponding wetting diagrams have been constructed in Cassie, Wenzel, and impregnation regions. It is shown that, under the same condition, modest deviations between the microscale and the macroscale models can be observed within the Cassie region, whereas these deviations have been enlarged in the Wenzel and impregnation regions as well as the Cassie–Wenzel transition region. These deviations are also correlated to the roughness of the surface. The reason can be attributed to the cooperative effect of the liquid–solid interfacial free energy and line tension. This study offers a fundamental understanding of wettability of ultrasmall droplets on a microscale geometric rough surface.
Co-reporter:Jiaxi Han, Kaijun Xie, Zhongjie Du, Wei Zou, Chen Zhang
Carbohydrate Polymers 2015 120() pp: 85-91
Publication Date(Web):20 April 2015
DOI:10.1016/j.carbpol.2014.12.011
•The β-CD functionalized polystyrene porous monolith was prepared.•The volume fraction of dispersed phase and the content of allyl-β-CD were studied.•The migration of allyl-β-CD towards the water/oil interface was investigated.•The enrichment of β-CD at interface improved adsorption capacity of phenol.A β-cyclodextrin (β-CD) functionalized polystyrene porous monolith was prepared by the following procedure: First, β-CD was modified with allyl bromide leading to allyl-β-cyclodextrin (allyl-β-CD); then a concentrated emulsion was prepared using a mixture of allyl-β-CD, styrene, and divinyl benzene as the continuous phase and water as the dispersed phase. In the third step, a β-cyclodextrin (β-CD) functionalized polystyrene porous monolith was obtained by copolymerization of allyl-β-CD and styrene followed by removal of the water phase. Since the allyl-β-CD contained both hydrophilic and hydrophobic groups, it tended to move towards the water/oil interface. As a result, the internal surfaces of the porous monolith were enriched with β-CD. This enrichment was indicated by X-ray photoelectron spectroscopy characterization. The high content of β-CD and the high specific surface area of the porous monolith both contributed to a high adsorption capacity. For example, the maximum adsorption of phenol was 5.74 mg/g. Importantly, the porous monolith could be easily regenerated and recycled through desorption with ethanol and it was found that the adsorption properties remained stable for at least five adsorption/desorption cycles.
Co-reporter:Gaiping Guo;Zhongjie Du;Wei Zou
Journal of Polymers and the Environment 2015 Volume 23( Issue 2) pp:183-189
Publication Date(Web):2015 June
DOI:10.1007/s10924-014-0682-7
Poly (vinyl alcohol) (PVA)/soy protein isolate (SPI) blend film plasticized with glycerol is fabricated by melting processing in presence of water. The structure and properties are investigated by Fourier-transform infrared spectroscopy, X-ray diffraction, differential scanning calorimeter, scanning electron microscope (SEM), mechanical testing, and thermo-gravimetric analysis (TGA). It is found that strong hydrogen bonds between soy protein and PVA macromolecules are formed. The incorporation of soy protein into PVA decreases the crystallinity of the latter. The crystallization and melting temperatures decrease with increasing SPI content. SEM shows that certain degree of phase separation occurs in the blend film, with soy protein phase finely dispersed in the PVA matrix. The PVA/SPI blend film possesses high flexibility even at high protein content, which ensures its potential applications as packaging film. TGA experiments shows that the incorporation of soy protein rendered the thermostability of the blend film.
Co-reporter:Lina Cui, Zhongjie Du, Wei Zou, Hangquan Li and Chen Zhang
RSC Advances 2014 vol. 4(Issue 52) pp:27591-27596
Publication Date(Web):06 Jun 2014
DOI:10.1039/C4RA02691H
A novel composite was constructed by the in situ growth of silver nanowires (AgNW) on multi-walled carbon nanotubes (MWCNT). Firstly, thiol groups were covalently bonded onto the surface of MWCNT by the esterification of thioglycolic acid with hydroxylated MWCNT. Reduced platinum (Pt) nanoparticles were then attached to the MWCNT via the thiol groups. In the presence of poly(vinyl pyrrolidone), Pt nanoparticles served as seeds for generating AgNW of uniform diameter. Finally, a MWCNT/AgNW composite with a conductive network structure was fabricated. The structure and morphology of the composite were measured by a variety of methods, including UV-visible extinction spectrometry, energy-dispersive spectrometry, X-ray diffractometry, Raman spectrometry and electron microscopy. An electrically conductive thin film of 80% transparency with a sheet resistance of 47.8 Ω sq−1 was prepared by coating the composite onto a polyethylene terephthalate film substrate.
Co-reporter:Yang Wang ; David K. Sang ; Zhongjie Du ; Chen Zhang ; Ming Tian ;Jianguo Mi
The Journal of Physical Chemistry C 2014 Volume 118(Issue 19) pp:10143-10152
Publication Date(Web):April 21, 2014
DOI:10.1021/jp501683d
The wetting behavior of diiodomethane on crystalline poly(tetrafluoroethylene) (PTFE), noncrystalline PTFE, and poly(vinylidene cyanide-alt-1H,1H,2H,2H-perfluorodecyl vinyl ether) surfaces are analyzed theoretically. By combining three-dimensional reference interaction site model with three-dimensional density functional theory, the theory provides the overall density and free-energy distributions of diiodomethane at the three surfaces. It is shown that surface roughness arising from polymer structure and configuration plays the crucial role in the surface tension and the wettability. Meanwhile, the contribution of chemical composition is also important to the surface tension by altering the intra- and intermolecular interactions and renormalizing the surface roughness. The predicted contact angles of a diiodomethane droplet on the three surfaces are in good agreement with the available experimental values, showing the theory is able to quantitatively evaluate the cooperative contributions of chemical composition and geometry to wettability.
Co-reporter:Hai Fu, Zhong-jie Du, Wei Zou, Hang-quan Li and Chen Zhang
Journal of Materials Chemistry A 2013 vol. 1(Issue 47) pp:14943-14950
Publication Date(Web):03 Oct 2013
DOI:10.1039/C3TA12844J
A carbon nanotube reinforced polypyrrole nanowire network was constructed by in situ polymerization of pyrrole in the presence of carbon nanotubes using cetyltrimethylammonium bromide micelles as a soft template. Carbon nanotubes as a reinforcer were embedded into a network of polypyrrole nanowires, thus retaining in the latter a complete network. The resulting network possessed a specific surface area of 112.1 m2 g−1 and a rough porous structure. The embedding of carbon nanotubes decreased the charge transfer resistance in the polypyrrole nanowires and allowed easy access and rapid diffusion of ions/electrons. When applied as a capacitive electrode, a specific capacitance of 183.2 F g−1 was observed at a current density of 8 A g−1. The specific capacitance retention was 85% after 1000 cycles at 1 A g−1. An asymmetric supercapacitor was fabricated using the network as a positive electrode and active carbon as a negative electrode, and when operated at a maximum voltage of 1.5 V, had a high energy density (15.1 W h kg−1 at 3000 W kg−1). A long-term cycling test of the asymmetric supercapacitor at a current density of 1 A g−1 displayed a capacitance retention of 72% even after 3000 cycles of charge and discharge.
Co-reporter:Hai Fu, Zhong-jie Du, Wei Zou, Hang-quan Li, Chen Zhang
Carbon 2013 Volume 65() pp:112-123
Publication Date(Web):December 2013
DOI:10.1016/j.carbon.2013.08.006
An easy method to synthesize a strongly coupled cobalt ferrite/carbon nanotube (CoFe2O4/CNT) composite with oxygen bridges between CoFe2O4 and reduced carbon nanotubes (CNTs) by calcining the precursor material was reported. The precursor was prepared by an electrostatic self-assembly of the exfoliated Co(II)Fe(II)Fe(III)-layered double hydroxide (CoFeFe-LDH) nanosheets and acid treated CNTs. The deoxygenation effect of ferrous ion (Fe2+) in CoFeFe-LDH nanosheets on the oxygen-containing groups of acid treated CNTs was investigated by X-ray photoelectron spectroscopy (XPS) measurement. After thermal conversion, the obtained CoFe2O4 was bonded to the reduced CNTs through Metal–O–C (oxygen bridge), which was characterized by XPS, Fourier transform infrared spectroscopy, and Raman spectroscopy. When applied as an anode for lithium-ion battery, the CoFe2O4/CNT composite exhibited a low resistance of charge transfer and Li-ion diffusion, good cycle performance, and high rate capability. At a lower current density of 0.15 A·g−1, a specific discharge capacity of 910 mA·h·g−1 was achieved up to 50 cycles. When current density was increased to 8.8 A·g−1, the CoFe2O4/CNT composite still delivered 500 mA·h·g−1.
Co-reporter:Yanhui Du, Zhongjie Du, Wei Zou, Hangquan Li, Jianguo Mi, Chen Zhang
Journal of Colloid and Interface Science 2013 Volume 409() pp:123-128
Publication Date(Web):1 November 2013
DOI:10.1016/j.jcis.2013.07.071
•CO2 adsorbent based on rich amine functionalized nano-silica was fabricated.•Polyacrylic acid acted as a multi-functional bridge.•CO2 adsorption capacity is 3.8 mmol/g at 100 KPa CO2, 40 °C.•The adsorbent exhibited a good selectivity for CO2–N2 separation.•The adsorbent could be easily regenerated.An easy strategy to obtain an effective carbon dioxide adsorbent based on rich amines functionalized nano-silica was proposed. Polyacrylic acid (PAA), acted as a multi-functional bridge, was firstly immobilized onto the surface of silica nanoparticles. Each carboxylic acid group was subsequently reacted with an amine group of alkylamines, and plenty of remained amines groups could be coated onto silica nanoparticles. As a result, the rich amines loaded nano-silica was fabricated and applied as CO2 adsorbent. The structures and morphologies of amines modified nano-silica were characterized by FTIR, TGA, TEM, and CHNS elemental analysis. Moreover, the effect of molecular weight of PAA and that of alkylamine on CO2 absorption capacity was discussed. As expected, SiO2–PAA(3000)–PEI(10000) adsorbent possessed remarkably high CO2 uptake of approximately 3.8 mmol/g-adsorbent at 100 KPa CO2, 40 °C. Moreover, it was found that the adsorbent exhibited a high CO2 adsorption rate, a good selectivity for CO2–N2 separation, and could be easily regenerated.
Co-reporter:Zuolong Liu, Zhongjie Du, Wei Zou, Jianguo Mi, Hangquan Li, Yihan Wang and Chen Zhang
RSC Advances 2013 vol. 3(Issue 41) pp:18849-18856
Publication Date(Web):07 Aug 2013
DOI:10.1039/C3RA43597K
A moisture-resistant CO2 adsorbent was designed and prepared. The adsorbent used porous polystyrene as a skeleton, surface modified with amine groups. The structure and morphology of the adsorbent were characterized using infrared spectroscopy, scanning electron microscopy, and energy-dispersive spectrometry. Due to the huge specific surface area covered by a large number of amine groups, such porous material could be applied for capturing carbon dioxide under atmospheric pressure. Under a pressure of 100 Kpa, 3.46 mmol g−1 of CO2 adsorption uptake was observed. The porous adsorbent also exhibited a high CO2 adsorption rate, excellent moisture resistance, good selectivity for CO2–N2 separation, and easy CO2 regeneration.
Co-reporter:Tao Zhang;Zhongjie Du;Wei Zou;Hangquan Li
Journal of Applied Polymer Science 2013 Volume 130( Issue 6) pp:4245-4254
Publication Date(Web):
DOI:10.1002/app.39706
ABSTRACT
Multiwalled carbon nanotubes (MWNTs) are covalently grafted with hydroxyl modified phosphazene, which constitutes a novel flame retardant structure, and introduced into ethylene-vinyl acetate (EVA) copolymer via melt blending. The structure and morphology of the phosphazene-wrapped MWNTs are characterized using Fourier transform infrared spectroscopy and transmission electron microscopy. The grafted phosphazene introduces phosphorus- and nitrogen-containing species onto the surface of MWNTs and thus improves thermal stability of EVA resin and the dispersion of MWNTs in EVA matrix. Thermogravimetric analysis and cone calorimeter analysis reveal that phosphazene and MWNTs produce a synergistic effect on the enhancement of the thermal stability and flame retardancy of EVA. Furthermore, SEM observation indicates that phosphazene accelerates the formation of char residue on the surface of MWNTs. The char residue fills the space in the network structure of MWNTs and glues the MWNTs together. The dense char/MWNTs layers constitute a heat and mass block and therefore a better flame retardancy is observed. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 4245–4254, 2013
Co-reporter:Tao Zhang, Zhongjie Du, Wei Zou, Hangquan Li, Chen Zhang
Polymer Degradation and Stability 2012 Volume 97(Issue 9) pp:1716-1723
Publication Date(Web):September 2012
DOI:10.1016/j.polymdegradstab.2012.06.014
Co-reporter:Nianjun Kang;Zhongjie Du;Hangquan Li;Zhehan Zhao
Journal of Applied Polymer Science 2012 Volume 123( Issue 3) pp:1675-1683
Publication Date(Web):
DOI:10.1002/app.34630
Abstract
A series of β-cyclodextrin-based epoxy resins were synthesized with different epoxy equivalent weights. Their chemical structures were characterized with Fourier Transform Infrared Spectroscopy (FTIR) and Nuclear Magnetic Resonance Spectroscopy (NMR) examination. These epoxy resins were cured using L-arginine as a curing agent, and the degradation behavior of the cured resins was evaluated under different acidic buffer solutions at 37°C. The degradable behavior of such epoxy resins suggested potential applications as environment friendly materials. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Co-reporter:Nianjun Kang;Zhongjie Du;Hangquan Li
Polymers for Advanced Technologies 2012 Volume 23( Issue 10) pp:1329-1334
Publication Date(Web):
DOI:10.1002/pat.2043
In this report, a novel phosphorus/silicon-containing reactive flame retardant, hexa(3-triglycidyloxysilylpropyl)triphosphazene (HGPP), was synthesized and characterized by Fourier transform infrared spectrometry and nuclear magnetic resonance spectra (1H, 31P, and 29Si), respectively. To prepare cured epoxy, HGPP had been co-cured with diglycidyl ether of bisphenol-A (DGEBA) via 4,4-diaminodiphenylsulfone as a curing agent. The mechanical, thermal, and flame retardant properties of the cured epoxy were evaluated by dynamic mechanical analysis, thermogravimetric analysis, and limiting oxygen index (LOI). According to these results, it could be found that incorporation of HGPP in the cured epoxy system showed good thermal stability, high LOI values, and high char yield at high temperature. As moderate loading of HGPP in the epoxy system, its storage modulus and glass transition temperature were higher than those of neat DGEBA. Copyright © 2011 John Wiley & Sons, Ltd.
Co-reporter:Nianjun Kang;Zhongjie Du;Hangquan Li
Journal of Applied Polymer Science 2012 Volume 124( Issue 6) pp:4915-4919
Publication Date(Web):
DOI:10.1002/app.35582
Abstract
Polymethyl(3-glycidyloxypropyl)siloxane (PMGS) was synthesized as a flame-retardant additive, which were cocured with diglycidyl ether of bisphenol-A (DGEBA) using 4,4′-diaminodiphenylsulfone as a curing agent. The structure of PMGS was confirmed through Fourier transform infrared and 1H-NMR spectra. The cured products were characterized with dynamic mechanical thermal analysis, thermogravimetric analysis, and oxygen index analyzer. With PMGS incorporated, the cured epoxy resin showed better thermal stability, higher limited oxygen index, and higher char yield. At moderate loading of PMGS, the storage modulus and glass transition temperature of the cured epoxy resin based on neat DGEBA were obviously improved. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Co-reporter:Hai Fu, Zhong-jie Du, Wei Zou, Hang-quan Li, Chen Zhang
Materials Letters 2012 Volume 78() pp:54-57
Publication Date(Web):1 July 2012
DOI:10.1016/j.matlet.2012.03.062
Multi-walled carbon nanotubes (MWNTs) were grafted with poly (acrylic acid) (PAA) forming PAA-g-MWNTs, which were subsequently neutralized with a sodium hydroxide solution resulting in sodium polyacrylate encapsulated MWNTs (PAANa-g-MWNTs). Then PAANa-g-MWNTs were introduced into polyetherimide (PEI) as an electrically conductive additive. The polymer-encapsulated MWNTs could be finely dispersed in the PEI matrix. Moreover, determinations of the electrical conductivity and electrochemical impedance spectra (EIS) of the nanocomposites indicated that the electrical conductive percolation threshold of PAANa-g-MWNTs in PEI was decreased obviously over that of pristine MWNTs, and partially because of the improved dispersion of the conductive filler, partially because of the joint efforts of the moderate ionic conductivity induced by PAANa with the electronic conductivity by MWNTs in the polymer matrix.Graphical abstractHighlights► PAANa-g-MWNTs were introduced into PEI as an electrically conductive additive. ► The percolation threshold was decreased from 4% of MWNTs to 1.75% of PAANa-g-MWNTs. ► The enhanced conductivity came from ionic conducting mechanism induced by PAANa.
Co-reporter:Wei Zou, Zhong-jie Du, Hang-quan Li and Chen Zhang
Journal of Materials Chemistry A 2011 vol. 21(Issue 35) pp:13276-13282
Publication Date(Web):08 Aug 2011
DOI:10.1039/C1JM11125F
A highly transparent and luminescent CdSe quantum dot (QD)/epoxy nanocomposite was prepared by mixing amido-functionalized QDs with an epoxy matrix. The original oleic acid ligand on the QDs was replaced by thioglycolic acid, and then primary amine groups were introduced via a reaction between the carboxyl group of thioglycolic acid and Schiff’s base. The QDs with amido-functionalized ligands showed a better dispersibility and higher optical properties in the epoxy matrix. It was found that the nanocomposite filled with 0.3 wt% modified green light-emitting QDs had a similar transparency to the neat epoxy and twice the luminescence intensity of nanocomposite-filled 0.3 wt% original QDs. Moreover, a QD/epoxy nanocomposite, which could emit clear white light by combining the unabsorbed blue excitation light and the re-emitted yellow light, was successfully fabricated by following the same strategy. The as-prepared QD/epoxy nanocomposite has potential applications in encapsulating materials in light-emitting diode.
Co-reporter:Wei Zou;Zhong-jie Du;Hang-quan Li
Polymer International 2011 Volume 60( Issue 5) pp:751-757
Publication Date(Web):
DOI:10.1002/pi.3005
Abstract
A facile approach is proposed for the fabrication of surface-modified CdSe quantum dots (QDs) with compatibility with various media and better dispersibility by self-assembly of a functionalizable comb polymer. The comb polymer was prepared from the reaction between the acyl chloride groups in poly(acryloyl chloride) and the hydroxyl groups in 1-octadecanol. With the combination of the compatibility and entanglement of the aliphatic chain in 1-octadecanol and similar aliphatic chain in oleic acid ligand of QDs, the comb polymer could cap on the QDs and thus endow them with functional groups. The structure of such a polymer was investigated using Fourier transform infrared spectroscopy. According to the reactivity of remaining acyl chloride groups in the comb polymer, the polymer ligands could be tailored to be various structures, and then lipophilic, hydrophilic and functional QDs were obtained. The fluorescence properties of the surface-modified QDs were investigated, and the morphologies and dispersions of different kinds of surface-modified QDs were characterized using transmission electron microscopy. Finally, homogeneous and stable dispersions of QDs in various media could be realized by adjusting the structure of the comb polymer. Copyright © 2010 Society of Chemical Industry
Co-reporter:Yilei Zhu;Zhongjie Du;Hangquan Li
Polymer Engineering & Science 2011 Volume 51( Issue 9) pp:1770-1779
Publication Date(Web):
DOI:10.1002/pen.21964
Abstract
The poly(vinyl alcohol) (PVA)-based nanocomposites embedded with modified multiwalled carbon nanotubes (MWCNTs) were prepared. To enhance the interfacial interaction between MWCNTs and PVA, acid-treated MWCNTs were grafted with PVA chains, compatibilizing MWCNTs and the matrix. The better dispersion of MWCNTs in PVA matrix was obtained by the introduction of MDI reaction bridges and then PVA molecules onto the surface of MWCNTs. Moreover, strong interaction between MWCNTs and PVA matrix was evidenced through the measurement results of the melting behavior, polarized Raman measurement, and nonisothermal crystallization behavior of the nanocomposites. Owing to the reinforcement of MWCNTs, the tensile strength and modulus of PVA nanocomposite containing 0.9 wt% MWCNTs were increased by 160.7 and 109.2%, respectively, compared to neat PVA. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers
Co-reporter:Jie Tu, Zhongjie Du, Hangquan Li, Chen Zhang
Colloids and Surfaces A: Physicochemical and Engineering Aspects 2011 Volume 375(1–3) pp:68-75
Publication Date(Web):5 February 2011
DOI:10.1016/j.colsurfa.2010.11.059
Hydrophilic surface modification of porous epoxy monoliths was carried out by introducing the initiator into the wall of pores and then polymerizing acrylic acid monomer onto the surface. The porous epoxy monolith was prepared via concentrated emulsion polymerization template. Before fully curing of epoxy, the free radical initiator was immobilized on the pore surface by swelling the porous epoxy monolith in initiator/acetone solution. After acrylic acid monomers were infiltrated into the pores and then polymerized, the hydrophilic polymer layers were generated on the wall of pores. The effects of the curing time of epoxy and the swelling time in solution on the morphology of poly (acrylic acid) layers were discussed. The polymerization of hydrophilic polymer on the pore surface of the porous monolith was investigated by scanning electron microscopy, transmission electron microscopy, and energy-dispersive spectrometer. The hydrophilic modification and the wettability of the surface of pores in porous epoxy monoliths were studied by water contact angle and water absorption measurement.Graphical abstractThe hydrophilic poly (acrylic acid) layer covered on the pore surfaces of the porous epoxy monolith after modification.Research highlights▶ Porous epoxy monolith was prepared via concentrated emulsion polymerization template. ▶ Initiator was swelled into the interface of pores before fully curing of epoxy. ▶ Hydrophilic modification of the pore walls of porous epoxy monoliths was realized.
Co-reporter:Wei Zou, Zhong-jie Du, Hang-quan Li, Chen Zhang
Polymer 2011 Volume 52(Issue 9) pp:1938-1943
Publication Date(Web):19 April 2011
DOI:10.1016/j.polymer.2011.02.043
A facile approach to introduce carboxyl groups onto the surface of CdSe quantum dots (QD) was achieved via oleic acid ligands self-assembly, and then CdSe quantum dots/epoxy fluorescence nanocomposites were successfully fabricated. The surface constitution of QD, the better dispersibility of QD in epoxy matrix, and the reactivity with epoxy of carboxyl groups functionalized QD were characterized by Fourier transform infrared (FT-IR), transmission electron microscopy (TEM), and differential scanning calorimetry (DSC), respectively. As the result of surface modification, the carboxyl groups functionalized QD could be stably and homogenously dispersed in chloroform and acid anhydride cured epoxy matrix. The fresh fluorescence as well as the toughening behavior of the QD/epoxy nanocomposites was presented.
Co-reporter:Jianhua Li;Zhongjie Du;Hangquan Li
Journal of Polymer Science Part B: Polymer Physics 2010 Volume 48( Issue 20) pp:2140-2147
Publication Date(Web):
DOI:10.1002/polb.22095
Abstract
A methodology for preparing porous epoxy monolith via chemically induced phase separation was proposed. The starting system was a mixture of an epoxy precursor, diglycidyl ether of bisphenol-A (DGEBA), a curing agent, 4,4′-diaminodiphenylmethane (DDM), and a thermoplastic polymer, polypropylene carbonate (PPC). As DGEBA was cured with DDM, the system became phase-separated having PPC particles dispersed in epoxy matrix. After PPC particles were removed by thermal degradation, a porous structure was obtained. The phase separation mechanism was determined by the initial composition and illustrated by a pseudophase diagram. The pore size increased with increasing the concentration of PPC and raising the curing temperature. The intermediate and final morphologies of the system were studied using optical and scanning electron microscopy, respectively. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2010
Co-reporter:Kejing Yu;Zhongjie Du;Hangquan Li
Polymer Engineering & Science 2010 Volume 50( Issue 2) pp:396-401
Publication Date(Web):
DOI:10.1002/pen.21529
Abstract
Blends of poly-ε-caprolactam (nylon6) and poly{2,6-diimidazo[4,5-b:4′5′-e]pyridinylene-1,4(2,5-dihydroxy) phenylene} (PIPD/nylon 6) have been prepared via a controlled polymer solution crystallization method. The crystallization behavior of nylon 6 in the blends was investigated using differential scanning calorimetry (DSC), x-ray diffraction (XRD), and polarizing microscopy (PLM). The results indicated that the presence of PIPD inhibited the nucleation rate of the crystallization of nylon 6, resulting in reduction in crystallization temperature, degree of crystallinity, and the perfection of crystal. Such influence was attributed to the formation of hydrogen bonds between nylon 6 and PIPD molecules. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers
Co-reporter:Jianli Wang;Zhongjie Du;Congju Li;Hangquan Li
Journal of Applied Polymer Science 2009 Volume 111( Issue 2) pp:746-752
Publication Date(Web):
DOI:10.1002/app.29099
Abstract
Inverse concentrated emulsions were prepared using aqueous colloidal silica suspension as the hydrophilic dispersed phase and a solution of diglycidyl ether of bisphenol-A (DGEBA), its curing agent polyamide resin, low molecular weight 650, surfactant nonyl phenol polyoxyethylene ether (NPE-4) in 4-methyl-2-pentanon as the continuous phase, which was expected to be used as the precursors of preparation of porous epoxy resins. The stability, i.e., the resistance to phase separation was studied. The effects of various parameters on the stability of the concentrated emulsions were investigated. The colloidal silica can strengthen the steric repulsion in the system and improve the stability. Viscosity of both phases played a major role in the stability. Precuring of the continuous phase provided an increased initial viscosity and enhanced the stability. Lower volume fraction of the dispersed phase can help to maintain stability of the concentrated emulsions. Properly increasing the curing rate, the concentrated emulsions may acquire a high viscosity in a short time, which retarded the phase separation. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Co-reporter:Ke-Jing Yu, Zhong-Jie Du, Hang-Quan Li, Chen Zhang
Materials Letters 2009 Volume 63(Issue 8) pp:664-666
Publication Date(Web):31 March 2009
DOI:10.1016/j.matlet.2008.12.028
By introducing the nano-CaCO3 into in-situ polymerization, a templated material of poly(2,6-diimidazo[4,5-b:4'5'-e]pyridinylene-1,4(2,5-dihydroxy)phenylene)(PIPD) with a narrow pore size distribution can be prepared synchronously. The results we obtained suggested that the nano-CaCO3 played as a nucleation agent during the polymerization, which led to the obvious improvement of formation PIPD nanospheres. The effects of the solvent on the formation of nanospheres have been also investigated. With the treatment of the methanesulfonic acid (MSA), PIPD nanospheres with more regular and ordered morphology were obtained. Pore size distribution of the templated material recorded by mercury intrusion porosimetry (MIP) showed an average pore size with narrow distribution and the porosity of 60.22%.
Co-reporter:Jianhua Li, Zhongjie Du, Hangquan Li, Chen Zhang
Polymer 2009 50(6) pp: 1526-1532
Publication Date(Web):
DOI:10.1016/j.polymer.2009.01.049
Co-reporter:Chunchuang Li, Zhongjie Du, Wei Zou, Hangquan Li, Chen Zhang
Reactive and Functional Polymers (March 2015) Volume 88() pp:24-30
Publication Date(Web):1 March 2015
DOI:10.1016/j.reactfunctpolym.2015.02.001
The polymer foam coated with zero-valent copper (Cu0) was designed and prepared for the removal of hexavalent chromium (Cr(VI)) in water. Firstly, porous poly(tert-butyl acrylate) was fabricated by concentrated emulsion polymerization and then acrylic acid groups were generated on the surface of foam by hydrolysis reaction. Secondly, with the help of the large amount reactive carboxylic acid groups, polyethyleneimine (PEI) were chemically grafted onto the surface by the reaction between amine group and acrylic acid group. Finally, zero-valent copper was reduced by sodium borohydride (NaBH4) and coated on the surface of polymer foam. Thus the copper functionalized porous adsorbent (Cu0–PEI–PAA) was constructed, and then applied for removing Cr(VI) from aqueous solution. The removal mechanism of Cr(VI) involved redox reaction by zero-valent copper and adsorption by amine groups, simultaneously. As a result, 99.5% of Cr(VI) could be removed within 2 h, and the maximum removal capacity for Cr(VI) of Cu0–PEI(1800)–PAA was 9.16 mg/g. Furthermore, the effect of initial concentration of Cr(VI), pH value, and temperature on the Cr(VI) removal was investigated. Therefore, the as-prepared zero-valent copper-loaded polymer foam could be an efficient and promising remediation material to remove Cr(VI) from wastewater.
Co-reporter:Hai Fu, Zhong-jie Du, Wei Zou, Hang-quan Li and Chen Zhang
Journal of Materials Chemistry A 2013 - vol. 1(Issue 47) pp:NaN14950-14950
Publication Date(Web):2013/10/03
DOI:10.1039/C3TA12844J
A carbon nanotube reinforced polypyrrole nanowire network was constructed by in situ polymerization of pyrrole in the presence of carbon nanotubes using cetyltrimethylammonium bromide micelles as a soft template. Carbon nanotubes as a reinforcer were embedded into a network of polypyrrole nanowires, thus retaining in the latter a complete network. The resulting network possessed a specific surface area of 112.1 m2 g−1 and a rough porous structure. The embedding of carbon nanotubes decreased the charge transfer resistance in the polypyrrole nanowires and allowed easy access and rapid diffusion of ions/electrons. When applied as a capacitive electrode, a specific capacitance of 183.2 F g−1 was observed at a current density of 8 A g−1. The specific capacitance retention was 85% after 1000 cycles at 1 A g−1. An asymmetric supercapacitor was fabricated using the network as a positive electrode and active carbon as a negative electrode, and when operated at a maximum voltage of 1.5 V, had a high energy density (15.1 W h kg−1 at 3000 W kg−1). A long-term cycling test of the asymmetric supercapacitor at a current density of 1 A g−1 displayed a capacitance retention of 72% even after 3000 cycles of charge and discharge.
Co-reporter:Wei Zou, Zhong-jie Du, Hang-quan Li and Chen Zhang
Journal of Materials Chemistry A 2011 - vol. 21(Issue 35) pp:NaN13282-13282
Publication Date(Web):2011/08/08
DOI:10.1039/C1JM11125F
A highly transparent and luminescent CdSe quantum dot (QD)/epoxy nanocomposite was prepared by mixing amido-functionalized QDs with an epoxy matrix. The original oleic acid ligand on the QDs was replaced by thioglycolic acid, and then primary amine groups were introduced via a reaction between the carboxyl group of thioglycolic acid and Schiff’s base. The QDs with amido-functionalized ligands showed a better dispersibility and higher optical properties in the epoxy matrix. It was found that the nanocomposite filled with 0.3 wt% modified green light-emitting QDs had a similar transparency to the neat epoxy and twice the luminescence intensity of nanocomposite-filled 0.3 wt% original QDs. Moreover, a QD/epoxy nanocomposite, which could emit clear white light by combining the unabsorbed blue excitation light and the re-emitted yellow light, was successfully fabricated by following the same strategy. The as-prepared QD/epoxy nanocomposite has potential applications in encapsulating materials in light-emitting diode.
