Study On Crystallization Behavior And Properties Of Poly(p-phenylene Sulfide) In Blends With Thermotropic Liquid Crystalline Polyester

As the sixth high performance plastics, phenylene sulfide (PPS) has been widely used in auto, electronics industry and military field, due to its good combination of properties such as high thermal stability and electrical insulating ability, corrosion resistance and self excellent flame retardance, which the demand of market is enlarged. But because the molecule chain of PPS is rigidity structure which is linked with benzene ring and contraposition sulfur atom, it has deadly shortcomings of quite low crystalline rate,impact strength and long anneal time, which limits the further use of it and indirectly increases its process cost. So How to obtain higher toughness or yield strength as the crystalline rate of material increases, but doesn't effect its hot performance and intensity, it has been a hot topic hunted by many polymer studiers in the field of modified PPS.The crystalline properties as well as the mechanical properties of PPS composites which filled with wholly and semi aromatics thermotropic liquid crystal polymer (TLCP) were studied in the paper. The contributions of the fillers for crystallization of materials were investigated by differential scanning calorimeter (DSC). To observe the spherocrystal dimension of PPS composites were observed by means of polarized light microscope (PLM) and X-ray diffraction (XRD). To analyze the mechanism of wear and the dispersion of fillers, the fracture surfaces of PPS composites were observed by means of scanning electron microscope (SEM).Farther the crystalline properties as well as the mechanical properties of PPS composites which filled with thermotropic liquid crystal polymer (TLCP) and fibre glass were studied.The following conclusions can be drawn from the paper:Though the DSC analysis, filled with a few W-TLCP or S-TLCP in PPS, it can notability increase the max crystallizing point and crystalline rate of PPS; the crystalline rate of PPS/W-TLCP composites boosts about three times than pure PPS, while the PPS/S-TLCP boosts about four-five times; it has few effect to crystallinity for the PPS/W-TLCP composites by cool-down rate, but PPS/S-TLCP composites is the very reverse.PLM of the PPS/TLCP composites indicate: W-TLCP acts as nucleating agent, while S-TLCP accelerates the growth of crystal nucleus.The study of SEM and mechanical properties on PPS/TLCP composites show: blended with 2wt% W-TLCP, it can refine the spherocrystal dimension of PPS and raise its tensile and impact strength.The nonisothermal crystallization and melting behaviors of PPS/TLCP/GF composites were investigated by DSC, the result reveals: The content of TLCP has great effect to crystallization process and crystallinity of PPS/TLCP/GF composites. Filled with TLCP (2wt %), the crystallinity of composites is low; But filled with TLCP (8wt %), the crystallinity of composites reaches above 75%.The study of SEM on PPS/GF/TLCP composites show: W-TLCP separates the interfaces between PPS and GF, dramatically reduces the mechanical properties of PPS/GF composites; while S-TLCP makes the interfaces of PPS and GF adhibit, improves and raises mechanical properties.To obtain the in-situ hybrid composites of best mechanical properties, the key not only lies on the form of TLCP's microfibrillar structure inside composites, but also depends on the interfaces structure between the base of resin and fibre.