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Chen X.,Southwest Jiaotong University | Chen X.,University of Sichuan | Yu J.,National Engineering Research Center for Compounding and Modification of Polymer Materials | Zhang Z.,Southwest Jiaotong University | Lu C.,University of Sichuan
Carbohydrate Polymers | Year: 2011

Cellulose fibers were extracted from the rice straw by a mechanical-high pressure steam technique. The structure, chemical composition and thermal properties of cellulose fibers were investigated by using Fourier transform infrared (FTIR) spectroscopy, wide-angle X-ray diffraction (WAXD), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). FTIR analysis and chemical composition of fibers demonstrate that this mechanical-high pressure steam treatment can result in partial removal of hemicellulose and lignin from the structure of fibers. WAXD results reveal that this results in improved crystallinity of the fibers. The rice straw fibers are determined to have diameters in the range of 5-10 μm. After mechanical-high pressure steam treatments, the thermal properties of the rice straw fibers from the TGA results are found to increase dramatically after treatments. The degradation temperature of the rice straw fibers reaches over 280 °C, which is reasonably promising for the use of these fibers in reinforced-polymer composites. © 2011 Elsevier Ltd. All rights reserved. Source


Cheng Q.,Tianjin Polytechnic University | Cui Z.,Tianjin Polytechnic University | Li J.,Tianjin Polytechnic University | Qin S.,National Engineering Research Center for Compounding and Modification of Polymer Materials | Yan F.,Tianjin Polytechnic University
Journal of Power Sources | Year: 2014

Poly(vinylidene fluoride)/polysulfone (PVDF/PSF) blend microporous matrix of polymer electrolyte for lithium ion battery is prepared via thermally induced phase separation (TIPS) technique. Because of only one parameter, i.e., the PSF/PVDF weight ratio, the membrane microstructure is conveniently controlled. The membrane formation mechanism of PVDF/PSF blend membranes is proposed with the assistance of a binary PSF/PVDF weight ratio-temperature phase diagram. In addition to studying the microstructure and mechanical properties of PVDF/PSF blend membrane, the relationship between properties of membrane, electrochemical performances of corresponding polymer electrolyte and membrane microstructure are also discussed in this paper. It is found that the addition of PSF not only increases ionic conductivity and electrochemical stable window of polymer electrolyte, but also markedly enhances charge-discharge performances of coin cell. The results reveal that PVDF/PSF blend microporous membranes prepared via TIPS technique can be used as polymer matrices of polymer electrolytes for lithium ion batteries. © 2014 Elsevier B.V. All rights reserved. Source


Ma T.,Tianjin Polytechnic University | Cui Z.,Tianjin Polytechnic University | Wu Y.,Tianjin Polytechnic University | Qin S.,National Engineering Research Center for Compounding and Modification of Polymer Materials | And 4 more authors.
Journal of Membrane Science | Year: 2013

PVDF/PMMA blend microporous membranes were fabricated via thermally induced phase separation (TIPS) process using a single diluent. Then the blend membranes were soaked in a liquid electrolyte to form polymer electrolytes. Finally, the polymer electrolytes were assembled in coin cells to test electrochemical properties. The effects of PMMA/PVDF weight ratio on the phase diagram of PVDF/PMMA/diluent system, morphology, crystallinity, crystal structure, mechanical properties and porosity of the membranes were discussed. The electrochemical properties of corresponding polymer electrolytes, such as ionic conductivity, cell charge-discharge capacity and discharge performance at different current densities, electrochemical stability windows, were also investigated in this paper. It was found that the cloud point of the system decreased and the membrane morphology changed from cellular structure to network structure with an increase in the amount of PMMA. Both electrolyte uptake of blend membranes and ionic conductivity of corresponding polymer electrolytes also increased with an increase in the amount of PMMA. The maximum ionic conductivity was found to reach 3.38×10-3S/cm at 25°C. The graphite/polymer electrolyte/LiFePO4 cells of blend membranes showed higher charge-discharge capacity and better discharge performance at different current densities. Electrochemical stability window was stable up to 4.7V (vs. Li+/Li). © 2013. Source


Chen M.,Southwest Jiaotong University | Xu Y.,Southwest Jiaotong University | Chen X.,Southwest Jiaotong University | Ma Y.,Southwest Jiaotong University | And 3 more authors.
High Performance Polymers | Year: 2014

In this article, thermoplastic polyurethane-microencapsulated ammonium polyphosphate (MTAPP) is prepared and well characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, and thermogravimetric analysis (TGA). MTAPP and APP are added onto polypropylene (PP) as a novel intumescent flame-retardant system to improve the flame retardancy of PP. The flammability, thermal stability, and mechanical properties of the flame-retardant PP composites are investigated by limiting oxygen index (LOI), UL-94 vertical burning test, cone calorimeter test (CCT), TGA, and mechanical properties tests. The results show that MTAPP exhibits better flame retardancy and thermal stability than that of the APP in the flame-retardant PP composites. The LOI value of the PP/MTAPP composite at the same loading level is higher than that of PP/APP composite. The dripping of MTAPP system disappears compared with APP system from UL-94 test. The results of the CCT also indicate that MTAPP is an effective flame retardant in PP. The improvement may be attributed to the better charring capacity of MTAPP from TGA. Additionally, the mechanical properties of MTAPP are better than those of APP in PP. © The Author(s) 2014. Source


Guo J.,National Engineering Research Center for Compounding and Modification of Polymer Materials | He M.,Guizhou Kumkuat Materials Ltd. | Li Q.,National Engineering Research Center for Compounding and Modification of Polymer Materials | Yu J.,National Engineering Research Center for Compounding and Modification of Polymer Materials | Qin S.,National Engineering Research Center for Compounding and Modification of Polymer Materials
Journal of Applied Polymer Science | Year: 2013

Nanocomposite of thermoplastic elastomer ethylene-octene copolymer/maleated ethylene-octene (POE/POE-g-MAH) with organo-montmorillonite (OMMT, 11 wt %) as masterbatch have been obtained by melt blending and it has been characterized by transmission electron microscopy (TEM). Flame retardant POE/POE-g-MAH/OMMT/ ammonium polyphosphate-pentaerythritol (APP-PER) (an intumescent flame retardant with 75 wt % ammonium polyphosphate and 25 wt % pentaerythritol) composites were prepared by using melting processing to study their structures, flame-retardancy, thermal, and mechanical properties. TEM showed exfoliated structures throughout POE/POE-g-MAH/OMMT masterbatch and POE/POE-g-MAH/OMMT/APP- PER nanocomposites. Synergistic effect was observed between OMMT and APP-PER resulting in significant improvements on thermal stability, flame-retardancy and mechanical properties in the POE/POE-g-MAH/OMMT/APP-PER nanocomposites. © 2013 Wiley Periodicals, Inc. Source

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