Co-reporter:Bingbing Guo;Qunfang Lin;Xiuge Zhao
Iranian Polymer Journal 2015 Volume 24( Issue 11) pp:965-975
Publication Date(Web):2015 November
DOI:10.1007/s13726-015-0385-5
Aluminum nitride/polyphenylene sulfide (AlN/PPS) composites were prepared using a melt-blended method, and the thermal, mechanical, morphology, and dielectric properties of the composites were systematically investigated. The results showed that the thermal conductivity of AlN/PPS composites increased with the addition of AlN, in various amounts, by forming a conductive network in the composites due to the filler. Wide-angle X-ray diffraction and scanning electron micrograph/energy dispersive spectrometry were employed to investigate the effects of AlN addition on the crystal property of the matrix. The test results showed that the crystallinity of the PPS increased with higher AlN content at first, and dropped when the volume content of AlN was over 15 vol%, that is because the AlN filler provided a heterogeneous nucleation effect on the PPS. Several thermal conductivity models were applied to predicate the thermal conductivity of AlN/PPS composites. The mechanical tests showed that the impact and flexural strength of the composites initially increased and decreased as the AlN contents increased. Thermogravimetric analyses showed that the thermal stability of PPS increased with the addition of AlN. The thermal conductivity of AlN/PPS composites was tested at different temperatures and it was found that by increases in temperature the thermal conductivity of the composites decreased. The electrical properties of the composites were also investigated.
Co-reporter:Jianfeng Yu;Hongxia Pan
Journal of Coatings Technology and Research 2014 Volume 11( Issue 3) pp:361-369
Publication Date(Web):2014 May
DOI:10.1007/s11998-013-9556-5
In this paper, a series of waterborne acrylic-modified epoxy hybrid dispersions were synthesized and successfully used as primers for coil coatings. Epoxy was phosphated to improve its adhesion to the metal substrate. The grafting reaction of acrylate monomers onto the high molecular weight epoxy resins was studied with infrared spectroscopy, differential scanning calorimetry, and nuclear magnetic resonance. The structure and resin molecules were found to be as expected and the film had the best performance when the acrylate monomer made up less than 40 wt% of the epoxy resin. Modification of the epoxy with phosphoric acid could increase the adhesion to the metal substrate. Better adhesion was achieved with greater amounts of phosphoric acid. R578 urea resin was found to be the most suitable for crosslinking of the resin in this system, and a paint film based on the resulting resin had excellent overall performance.
Co-reporter:Juntao Tang, Chuanjie Fan, Qunfang Lin, Xiaodong Zhou
Colloids and Surfaces A: Physicochemical and Engineering Aspects 2014 Volume 459() pp:65-73
Publication Date(Web):5 October 2014
DOI:10.1016/j.colsurfa.2014.06.044
•Stable, elastic and transparent urea–formaldehyde microcapsules containing tetrachloroethylene.•Sodium carboxymethyl cellulose: protective colloid in one-step method.•The surfactant amount and some crucial synthesis conditions have been optimized.Stable, elastic and optically transparent microcapsules containing tetrachloroethylene (TCE) as internal phase were prepared by in situ polymerization of urea–formaldehyde (UF) using the one-step method. For the first time, sodium carboxymethyl cellulose (NaCMC) was applied into the one-step system as a protective colloid. Microcapsules prepared under different conditions were characterized by scanning electron microscopy, optical microscopy, and thermogravimetric analysis. The results show that NaCMC-based microcapsules can exhibit better thermal and barrier properties than Gum Arabic (GA)-based ones. By formation of capsule wall with more compact microstructures, the NaCMC-based microcapsules can give potential application in encapsulated electrophoretic display systems. The system combining sodium dodecyl sulfate (SDS) and NaCMC together was also investigated. It is suggested that SDS can play an important role during the microencapsulation process, by improving the yield as well as the barrier properties of the products, but also resulting in negative effects at higher ratios of SDS-NaCMC. Other operation conditions such as different molar ratio of reactants (formaldehyde/urea) and addition of ammonium chloride (NH4Cl) were been studied as well.
Co-reporter:Jian Chen, Hui Bi, Shengrui Sun, Yufeng Tang, Wei Zhao, Tianquan Lin, Dongyun Wan, Fuqiang Huang, Xiaodong Zhou, Xiaoming Xie, and Mianheng Jiang
ACS Applied Materials & Interfaces 2013 Volume 5(Issue 4) pp:1408
Publication Date(Web):February 7, 2013
DOI:10.1021/am302825w
A novel architecture of graphene paper is proposed to consist of “1D metallic nanowires/defect-free graphene sheets”. Highly conductive and flexible papers of 1D silver nanowires (Ag NWs) and chemical vapor deposition (CVD) graphene sheets as an example were fabricated by a simple filtration method. CVD graphene paper possesses much higher electrical conductivity of 1097 S/cm, compared with other reported carbon-related papers (graphene, carbon nanotube, etc.). With the addition of Ag NWs to form Ag NWs/graphene paper, the electrical conductivity is further improved up to 3189 S/cm, even higher than ∼2000 S/cm of bulk graphite. Ag NWs/graphene papers have very good flexibility with the only <5% loss of electrical conductivity over 500 times mechanical bending. Highly conductive composite papers have potential in high-performance, flexible energy conversion and storage devices.Keywords: flexible paper; graphene; highly electrical conductivity; silver nanowires;
Co-reporter:Chuanjie Fan;Juntao Tang
Journal of Applied Polymer Science 2013 Volume 129( Issue 5) pp:2848-2856
Publication Date(Web):
DOI:10.1002/app.39008
Abstract
This study investigates the role of ammonium chloride in the process of preparing poly (urea-formaldehyde) (PUF) microcapsules using the one-step method. Scanning electron microscopy (SEM) and optical microscopy (OM) were used to observe the morphology of the microcapsule. The results showed that the addition of ammonium chloride in the one-step process of preparing PUF resin microcapsule decreases the pH of the system. The decrease in pH of the system is due to the reaction between ammonium chloride and formaldehyde, and more so due to the reaction between ammonium chloride and hydroxymethyl urea. In addition to reducing the pH of the system, the reaction between ammonium chloride and urea-formaldehyde resin can generate surface active substances, which drives the formed UF nanoparticles to enrich the surface of the dispersed phase. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Co-reporter:Fan Chuanjie;Tang Juntao;Zhou Xiaodong
Iranian Polymer Journal 2013 Volume 22( Issue 9) pp:665-675
Publication Date(Web):2013 September
DOI:10.1007/s13726-013-0165-z
The physical properties of microcapsules are strongly influenced by the synthetic conditions used for their preparation. To prepare microcapsules possessing a smooth surface morphology, high mechanical strength, and reduced permeability of the core material, in situ polymerization in an oil-in-water emulsion was performed using poly (urea–formaldehyde) and tetrachloroethylene as the shell and core materials, respectively. The influence of the synthetic conditions, including the initial pH value, concentration of wall material, concentration of NaCl, and heating rate, on the properties of the resulting microcapsules was investigated systematically by an orthogonal factorial design. The physical properties of the microcapsules were characterized using scanning electron microscopy and optical-photographic microscopy. The results showed that the concentration of shell material has a substantial effect on the mechanical strength of the microcapsules. Additionally, a slow heating rate and high initial pH value enhance the preparation of well-defined spherical microcapsules having excellent barrier properties. Finally, a moderate concentration of sodium chloride can remarkably improve the compactness of the capsule wall. The optimum conditions, determined on the basis of utilization of wall material, are as follows: initial pH value: 3.5; concentration of shell material: 3.6 × 10−2 g/mL; heating rate: 0.5 °C/min; and concentration of sodium chloride: 5.0 × 10−2 g/mL.
Co-reporter:Xuan Xie, Yunwen Wu, Yiyang Kong, Zixiao Zhang, Xiaodong Zhou
Colloids and Surfaces A: Physicochemical and Engineering Aspects 2012 Volume 408() pp:104-113
Publication Date(Web):20 August 2012
DOI:10.1016/j.colsurfa.2012.05.038
Multilayer core–shell structure hollow spheres were synthesized on the basis of hollow glass sphere (HGS) along with magnetic layer and conducting layer. The deposition of ferrite compound was conducted via chemical co-precipitation method onto HGS surface using ammonium acetate stabilizing precursor solution which performed as chemical plating process. The ratio of ammonium acetate: metal ion appeared to be critical when forming ferroferric oxide compounds. Sequentially, in situ chemical oxidative polymerization in H2O/C2H5OH/5-sulfosalicylic acid/pyrrole/FeCl3 system consequently obtained multilayer HGS@Ferrite@Polypyrrole composites. 5-Sulfosalicylic acid-FeCl3 constitutes a doping-initiating chelate which was found to provide good compactness and uniformity resulting in good conductivity. Qualitative characterization proved the core–shell structure and encapsulation effect. Doping amount and organic/inorganic ratio was quantitatively calculated. The HGS@Ferrite@PPy composite has remarkable excellent properties. The magnetization reaches 20.61 emu/g as soft magnetic materials, with a hysteresis loop presenting superparamagnetic whose coercivity and remnant magnetization hitting zero. The conductivity was as high as 16.5 S/cm much higher than other composites with similar structure. The cavity effect, magnetic loss and conducting loss combined provide this kind of material good electromagnetic wave absorption effect under low addition amount.Graphical abstract.Highlights► Hollow glass spheres@ferrite@ polypyrrole composite. ► Ratio of ammonium acetate: metal ion is critical to stabilize chemical plating process. ► Remarkable excellent superparamagnetic magnetic property and conductivity. ► Combined absorption of cavity structure, magnetic layer and conducting layer.
Co-reporter:Shuanghui Deng, Xiaodong Zhou, Chuanjie Fan, Qunfang Lin, Xinggui Zhou
Composites Part A: Applied Science and Manufacturing 2012 Volume 43(Issue 6) pp:990-996
Publication Date(Web):June 2012
DOI:10.1016/j.compositesa.2012.01.004
In this work, diblock copolymer Hydroxyl-Terminated poly (n-butylacrylate)-b-poly (glycidyl methacrylate) (OH-PnBA-b-PGMA) was synthesized by atom transfer radical polymerization (ATRP) and was then introduced into the interface between carbon fiber and epoxy resin. Micro-Raman spectroscopy and microbond test were employed to study the influence of grafted polymers on the interfacial properties. From the Micro-Raman spectroscopy results, the interfacial thermal stress in carbon fiber/epoxy resin micro-composite decreases from 546.9 MPa to 451.9 MPa due to the grafting of OH-PnBA180-b-PGMA70 on the carbon fiber. Meanwhile, the interfacial shear strength (IFSS) value increases rapidly from 29.8 MPa to 52.3 MPa, measured by microbond test. Therefore, it can be concluded that such a diblock copolymer can effectively both release the thermal stress and improve the interfacial adhesion. Moreover, it proves that the length of PnBA block has great influence on the interfacial properties of carbon fiber/epoxy composite.
Co-reporter:Xuan Xie, Xiaodong Zhou
Colloids and Surfaces A: Physicochemical and Engineering Aspects 2011 Volume 386(1–3) pp:158-165
Publication Date(Web):5 August 2011
DOI:10.1016/j.colsurfa.2011.07.015
Metal or alloy hollow structures were studied to synthesis low density conducting materials, while conducting polymer received more attention for its low-cost and environmental stability. A buffer system was constituted in this paper, which can reduce concentration gradient in polymerization process to improve uniformity and conductivity. A simple route has been developed to obtain low density core–shell hollow borosilicate glass sphere (HBGS)@polypyrrole composite. Polypyrrole (PPy) was chemically grafted from amino group rich layer onto HBGS. H2O/C2H5OH/5-sulfosalicylic acid/pyrrole/FeCl3 system could be regarded as a polymerization buffer system. Fourier infrared spectrum (FT-IR) and X-ray diffraction (XRD) analysis confirmed the perfect capsulation. Scanning electron microscope (SEM) images showed the thickness and surface morphology. Thermogravimetric analysis was conducted to investigate the thermal stability. The conductivity was determined using standard four-point probe method. The probable formation mechanism of the system was proposed on the basis of the experimental results, correlative formula was also calculated fitting the modules.Graphical abstractHighlights► Hollow borosilicate glass spheres@polypyrrole composites with core–shell structure. ► 5-Sulfosalicylic acid (SSA): emulsifier, dopant and chelate reagent with initiator. ► H2O/alcohol/SSA/pyrrole/FeCl3 appears to be buffer system for polymerization. ► Thickness and conductivity was designable and correlative formula fits the modules.
Co-reporter:Chuanjie Fan
Polymer Bulletin 2011 Volume 67( Issue 1) pp:15-27
Publication Date(Web):2011 June
DOI:10.1007/s00289-010-0355-1
Microcapsules containing tetrachloroethylene as an internal phase were prepared by in situ polymerization of urea–formaldehyde (UF) without prepolymerization. The effects of different emulsifiers on the process of microencapsulation and morphology of microcapsules were investigated. The results show that the emulsifier gum arabic (GA) can effectively slow down the deposition rate of resin onto the oil/water interface, which can lead to smooth and compact surface of microcapsules. The surface activity of GA was also enhanced by complex formation of gum arabic and sodium dodecyl benzene sulfonate. The microcapsules represent good thermal and barrier property as a result of the formation of capsule wall with compact microstructure.
Co-reporter:Huan Zhai;Li Fang;Ai Lu
Journal of Applied Polymer Science 2010 Volume 115( Issue 4) pp:2019-2027
Publication Date(Web):
DOI:10.1002/app.31214
Abstract
The prepreg of continuous glass fiber reinforced poly(phenylene sulphide) (PPS) was prepared using the powder impregnation technique and cut into the pellets, in which the length of glass fibers was the same as the pellets. After injection molding, the mechanical properties were tested and the effects of the pellet length, fiber content, and thermal treatment on the mechanical properties at different temperatures were studied. It is found that the tensile strength and flexural strength of 6-mm pellet sample are slightly higher than that of 3- and 12-mm pellet samples. The tensile strength, flexural strength, and modulus decrease significantly with increasing the temperature. The notched Izod impact strength at 85ºC is higher than both at 25ºC and 205ºC. At 205ºC, the glass fiber reinforced PPS composites can still keep better mechanical properties. When the fiber content ranges from 0 to 50%, the mechanical properties increase with increasing the fiber contents at different temperatures, except the notched Izod impact strength do not further increase at 145 and 205ºC with raising the fiber content from 40 to 50%. Thermal treatment could improve the mechanical properties of the composites at higher serving temperature. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Co-reporter:Chuanjie Fan, Xiaodong Zhou
Colloids and Surfaces A: Physicochemical and Engineering Aspects 2010 Volume 363(1–3) pp:49-55
Publication Date(Web):20 June 2010
DOI:10.1016/j.colsurfa.2010.04.012
A series of microcapsules were prepared by in situ polymerization with poly(urea–formaldehyde) as the shell material and glass beads as the core material. Glass beads were chosen as the core material because their size distribution was narrow and their surface was easily changed to be hydrophobic. The respective effects of initial pH value, concentration of wall material and surfactant, stirring rate on the state of microencapsulation were investigated systematically. The results showed that the surface morphology of the microcapsule depends mainly on the final pH value and stirring rate. A higher final pH value and faster stirring rate helped to prepare a smoother microcapsule. Addition of ammonium chloride was found to be very important in preparing of PUF microcapsules. The involvement of ammonium chloride caused a substantial drop in the pH value during reaction and enhanced the deposition of UF nanoparticles onto the surface of microcapsule.
Co-reporter:Yin Li, Qunfang Lin, Lingxia Chen, Xiaodong Zhou
Composites Science and Technology 2009 Volume 69(11–12) pp:1919-1924
Publication Date(Web):September 2009
DOI:10.1016/j.compscitech.2009.04.008
To control the interfacial structure of glass fiber-reinforced composites, triblock copolymer coupling agents polystyrene-block-poly(n-butylacrylate)-block-poly(γ-methacryloxypropyltrimethoxysilane), (PS-b-PnBA-b-PMPS) were synthesized by atom transfer radical polymerization, then were chemically grafted on the glass fiber surfaces with a sufficiently high grafting density. When the grafted glass fibers are embedded in polystyrene (PS) matrix melt, copolymer brushes assemble at the interface of glass fiber/PS system to form the hemispherical domain morphology, where PnBA blocks form the inner core collapsing on fiber surface, while the outer layer PS blocks shield the PnBA blocks from PS homopolymer melt and entangle with the molecular chain of PS homopolymer. The influence of molecular architecture and organization of triblock copolymer coupling agents on the interfacial shear strength of glass fiber/PS system was investigated by means of Microbond Test. It is found that an increase in the PS block lengths is of advantage to the interfacial shear strength. A PnBA block length about the degree of polymerization (DPn) of 50 is desirable for the interfacial shear strength.
Co-reporter:Jingqiang Hou;Zhijun Sui;Xinggui Zhou
Polymer International 2009 Volume 58( Issue 5) pp:564-569
Publication Date(Web):
DOI:10.1002/pi.2569
Abstract
BACKGROUND: To overcome the self-agglomeration of carbon nanofibers (CNFs), a number of studies have dealt with surface modification of CNFs to improve their wettability. In this work, a novel, simple and practical approach based on the introduction of methacrylate units to graft polymers onto the surface of CNFs is proposed.
RESULTS: The functionalized CNF samples were characterized using Fourier transform infrared and Raman spectroscopy, thermal gravimetric analysis and transmission electron microscopy. The molecular weight of grafted polystyrene (PS) is influenced by the monomer feed ratio. The stabilities of various CNF dispersions were measured using an optical analyzer. When the content of grafted PS is 34.2%, the functionalized CNFs attain a stable dispersion in xylene.
CONCLUSION: In the presence of methacrylate units, PS has been successfully grafted onto the surface of CNFs via an in situ polymerization. Moreover, the introduction of methacrylate units opens the functionalization of CNFs to other routes. Copyright © 2009 Society of Chemical Industry
Co-reporter:Fan Chuanjie ;Zhou Xiaodong
Polymers for Advanced Technologies 2009 Volume 20( Issue 12) pp:934-939
Publication Date(Web):
DOI:10.1002/pat.1342
Abstract
Preparation of microcapsules applied to the fabrication of self-healing composites has attracted a lot of attention. However, the leakage of core material from the microcapsule is a major problem in self-healing microcapsules. Proper dispersion of layered silicates within the wall of microcapsule is a strategy for improving the barrier properties of the microcapsule. In the present study, poly(urea-formaldehyde) (PUF) microcapsules containing dicyclopentadiene (DCPD) were prepared by in situ polymerization. For the preparation of UF/clay nanocomposite microcapsules, acid-modified montmorillonite (H-MMT) was used as an effective catalyst for the condensation of urea and formaldehyde, and the condensation polymerization in the galleries resulted in the delamination of the clay, as confirmed by TEM and XRD analysis. Scanning electron microscopy (SEM) was applied to observe the morphology of the microcapsules and the barrier property of microcapsules was investigated by thermal gravimetry (TG) analysis and mass release method. On comparison with conventional microcapsules (CMs), nanocomposite microcapsules (NCMs) have better barrier property. This can be attributed to the nanocomposite structure of the microcapsules, where nanosized montmorillonite dispersed in UF to decrease the core material cross-over. Copyright © 2008 John Wiley & Sons, Ltd.
Co-reporter:Yin Li;Lingxia Chen
Journal of Materials Science 2008 Volume 43( Issue 15) pp:5083-5091
Publication Date(Web):2008 August
DOI:10.1007/s10853-008-2588-z
A kind of di-block copolymer polystyrene-block-poly(γ-methacryloxy-propyltrimethoxysilane) (PS-b-PMPS) with different PS block length and a kind of tri-block copolymer polystyrene-block-poly(n-butylacrylate)-block-poly(γ-methacryloxypropyltrimethoxysilane) (PS-b-PnBA-b-PMPS) with different PnBA block length were synthesized by atom transfer radical polymerization (ATRP), in which PS was a ‘hard’ block and PnBA was a ‘soft’ block. The interfacial crystallization behaviors of glass fiber/polypropylene systems modified with different coupling agents MPS, PS-b-PMPS, and PS-b-PnBA-b-PMPS were investigated on different crystallization conditions. Transcrystallinity could not be induced on non-isothermal crystallization or without maleic anhydride (10%) in polypropylene, but it appeared when glass fibers were treated with common silane coupling agent γ-methacryloxypropyltrimethoxysilane (MPS) and di-block copolymer coupling agent PS-b-PMPS in 135 °C isothermal crystallization without shear and 150 °C isothermal crystallization with shear. However, it disappeared at the interface when the samples were treated with tri-block copolymer coupling agent (PS-b-PnBA-b-PMPS) either under static or shear-induced condition. It might be that the flexible interlayer formed by the flexible block PnBA of PS-b-PnBA-b-PMPS could relax not only the thermal stress resulted from interface temperature gradient arising from sample cooling for crystallization, but also the shear stress induced by fiber/matrix interface shear.
![Poly[oxy[methyl(3,3,3-trifluoropropyl)silylene]]](http://img.cochemist.com/ccimg/25800/25791-89-3.png)
![Poly[oxy[methyl(3,3,3-trifluoropropyl)silylene]]](http://img.cochemist.com/ccimg/25800/25791-89-3_b.png)
