Study On The Synthesis, Structure And Performance Of High Molecular Weight Polyarylene Sulfide Sulfone

Polyarylene sulfide sulfone (PASS) and poly(thenylene sulfide) (PPS) are both excellent high-performance poly(arylene sulfide) thermoplastics with outstanding nature of heat resistant ,corrosion resistant, radiation resistance, fire retardant, mechanical behaviors , dimensional stability and electrical property and had already been widely used as structural polymer. But PASS is amorphous, with the glass transition temperature (Tg) around 215℃, and its thermal stability and conservation rate of strength at high temperature environment are superior to that of semi crystalline PPS, which enable PPSS suitable for preparing high performance resin-based composites. Meanwhile, PASS is an excellent substance for membrane material, which can serve as insulation film in hot circumstances and as separating membranes in exacting terms. The high performance which PPSS hold made it is widely used in automobile industry, mechanical industry, aviation industry, military industry and etc as high performance engineering plastics and resin-based composites. In the beginning of this paper, all kinds of the resins of (Polyarylene sulfide) PAS were sorted. The performances and synthesis methods of each kind were also introduced. Some shortcomings of PASS which is a very important kind of PAS were pointed out at the same time. The target of this paper which would focused on the research work of the synthesis, structure and performance, composites'processing of new PASS resin were then conformed. In the paper, many creative and exploratory works were done, and a series of research finding were accordingly achieved: Firstly, with 4,4-dichloro diphenylsulfone (DCDPS), Na2S·XH2O and unique catalytic system, the polymerization reaction was carried out in polar organic solvent at atmospheric pressure, which is distinguished from the synthesis at high pressure at abroad, and high molecular weight PASS polymers were obtained. The optimum technological conditions of synthesis of PASS resin at normal atmosphere were gained by exploring the synthetic methods of PASS elaborately and repeatedly, which had excellent stability, high-viscosity product and good repeatability, and high molecular weight PASS resin with the maximum viscosity of 0.615g/dl was attained, which was a little higher than that of 0.610g/dl at high pressure reported at abroad. The synthetically technology conditions of the high molecular weight PASS at a 100-liter scale were groped for and got through and a series of ten-kilogram PASS resins were obtained. Secondly, the structure and performances of PASS resins and PASS membranes were researched thoroughly. The chain structures of PASS resins were characterized by infra-red spectrometry (IR), ultraviolet spectra (UV), Laser-Raman spectrum (LR), nuclear magnetic resonance spectroscopy (NMR) and so on, and the result showed that the anticipative PASS was synthesized. The aggregation structure of PASS was studied by X-ray diffraction (XRD), small angel laser light-scattering (SALS), scanning electron microscopy (SEM), atom force microscope (AFM), all of which have concluded that the untreated PASS sample are amorphous, and that the one annealed at suitable temperature has gave birth to short-range order structure; which can enhance the heat endurance. Through the torsional braid analysis (TBA) of PASS, other types of molecular chain morphology changes were founded beside the glass transition and the short-range order structure and break temperature were defined, and the preliminary analysis of the formation of secondary ordered structure has determined the research aspect. The DSC and TGA of PASS showed that PASS has excellent thermal stability, and during certain viscosity range, the thermal stability and glass transition temperature was increasing as the viscosity aroused. When the viscosity reached certain value or critical value, the property of PASS was driving to stability. From the research of dissolvability of PASS, it can be obviously conformed that PASS is a kind of resin to excellent chemical corrosion resistant property. The processing fluidity of PASS was also be studied by means of melting indexing and be tentatively discussed. Thirdly, the processing condition of twin-screw extruding and inject modeling of PASS resin, alloy and composites whose performances and structures have been elementarily characterized were explored. The methods of solution dipping and melt impregnating to prepare GF cloth reinforced PASS laminated board were also studied. The results showed that the flexural strength of PASS/GF cloth composite at the temperature of 180℃was 70% of that at room-temperature, indicating that PASS was more suitable for applying in high-temperature environment than Poly (phenylene sulfide).Then, PASS film was gained through solution casting method; PASS flat membrane and hollow fiber membrane were successfully prepared by immersion precipitation processes (L-G processes). The pore size and size distribution could be controlled by adjusting the precipitant, making the membrane suitable for various requirements of separating application. The integration structure of PASS membrane was observed through SEM and AFM, and local short-range order structure was founded on the surface of PASS after heat treating at suitable temperature firstly in the world. Such secondary ordered structure was nanometer size, appearing granular and fibrous. The untreated and treated PASS samples were analyzed by IR and electron energy spectroscopy (XPS), and concluded that the nanometer sized short-range order structure formed after heat treating was physical change, which can enhance the heat endurance, solvent resistance and mechanical property (of the PASS film). Meanwhile, the preparation and characterization of PASS/PPS was explored, which has laid a foundation of further research. Finally, ways of chemical structure modification were employed to improving the performance of PASS resin and several kinds of PASS copolymers were synthesized. Among these copolymers, PASS/S could improve the fluidity of PASS; B-PASS and PASS/K could increase the heat resistance and usage temperature of PASS. Moreover, the method of introducing new chain construction unit to substitute modify was achieved, by means of which the imide ring was successfully introduced into the principal chain of PASS and PASSI , which is a new kind of heat resistant resin and have the advantages of both thermoplastics and thermosets, was achieved. The work is meaningful to the further study of high temperature resistant materials. From the work of this paper, it can be concluded that the high molecule weight PASS which was polymerized in the paper can be used as high performance structural material after the processions of various methods, and the high temperature performance of PASS is better than that of PPS, and for its special functional property, PASS can be made up H-degree insulation film and separating membrane with heat resistance and corrosion resistance properties. All of above indicate that PASS can be further developed into a kind of material with both functional property and high performance and with brilliant future. Sichuan University is serving as the authoritative research centre of PAS. It is the responsible and duty of Sichuan University to keep on the research and development of PAS to hold the advanced level of the research of our country and to make our country to serve as a key role in the field of advance material.