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Study on the Polymerization and Spinning of Poly(P-Phenylene Sulfide)

Author: ZhangHao
Tutor: LiuZhaoFeng
School: Donghua University
Course: Materials Science
Keywords: poly(p-phenylene sulfide) high molecular weight fiber polymerization melt-spinning thermal property
CLC: TQ340.6
Type: Master's thesis
Year: 2007
Downloads: 90
Quote: 5
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Abstract


As an innovative high-performance synthetic fiber, polyphenylene sulfide（PPS） fiber has excellent resistance to chemical corrosion, good thermal stability and electric insulation, with mechanical tenacity comparable to Nomex fiber. As for its excellent properties, the fibers and fabric made from it have been widely used in industrial applications. Especially it plays an irreplaceable role in high temperature filter area. Now, the developed countries like USA, Japan are quickly pushing their studies on PPS fibers. However, the research on the synthesis of fiber-grade polyphenylene sulfide and spinning in our country is still at the beginning stage, especially the related reports on PPS fiber is rare.Using sodium sulfide （Na2S） and p-dichlorobenzene （p-DBC） as raw materials, a linear and high molecular weight PPS has been prepared in N-methyl-2-pyrrolidone （NMP） at high pressure by two-step method in this paper. Studies are concentrated on the effects of the reaction conditions, such as reaction time, precursor ratio, water content of monomers etc. on intrinsic viscosity of the prepared powder and the relation between the growth of molecular weight and reaction time of polymerization. The chemical structure of the prepared power was investigated by Fourier transform infrared spectroscopy and raman spectroscopy. Melting points （Tm） and mass loss temperature （Td） of the resin were investigated by DSC and TGA.The experimental result showed that the synthesis of PPS were influenced by many factors such as reaction time, precursor ratio, water content etc. When the mole ratio of Na2S and p-DBC was slightly higher than the ideal value, reaction effect was better and production rate was higher. With the decreasing of water content, the intrinsic viscosity of the prepared powder was increasing. While the water content was lower than a certain value, the intrinsic viscosity of the prepared powder assumed drop tendency. When the rest conditions were constant, along with time extension, the intrinsic viscosity of the prepared powder increased and the melt point of the prepared powder raised. The catalyst played very important role in enhancing the molecular weight. On the one hand it improved the solubility of polymer in NMP, on the other hand it enhanced the reaction activity.Using fiber-grade polyphenylene sulfide resin as raw materials, the freshly spun fiber was prepared by the method of melt spinning. Through drawing and heat set, the product PPS fiber was prepared. In the paper, the selection and the pre-treatment of raw material and the effect of spinning conditions on fiber-forming property were discussed firstly, including the spinning temperature, rate of extrusion and jet stretch ratio etc. Secondly, the after-treatment process of PPS fiber was explained. Of these, the effect of process parameters such as drawing ratio, drawing temperature and heat-treating conditions on mechanical properties of PPS fiber were discussed in detail. Thirdly, we tested the fiber using DSC, SEM and X-ray diffraction etc. and analyzed the super-molecular structure and properties of PPS fiber. The results indicated that through drawing, the degree of orientation of PPS fiber increased obviously. And by annealing, the fibrillation had complete lamellar crystal. Then the macroscopic mechanical properties of fiber were improved obviously.The thermal decomposition behavior of PPS fibers had been explored using TG-DSC coupling technology in N2。Through the studies on the TG and DTG curves, it is found that there is no weight loss of PPS fiber before 500℃, the greatest weight loss appears between 520℃and 600℃, and after that it is a process of slow weight loss. DSC curves exhibit that the thermal decomposition reaction of PPS fibers is not single in the whole process of weight loss. Moreover, PPS fibers had been experimented on heat treatment, and some relations between dry heat shrinkage, tenacity retention and heat treatment time and heat treatment temperature have been studied.

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