Preparation And Property Study Of Polyphenylene Sulfide Composites And Blends

Polyphenylene sulfide is new-type of thermal plastic with high performance. It is widely used in various areas especially in Electronic Appliance for with high strength, good heat resistance, inflaming retarding, electric insulating and dimensional stability properties. So with the electron devices miniaturized, better heat conductivity is required for materials. Compared with metals and ceramics, PPS has poor heat conducting property, which constrains its application. In addition, general PPS resin is lack of toughness because of its low molecular weight and stiffness. This thesis mainly study on the modification of PPS to improve its heat conductivity and toughness by melt-blending method.According to the research about the improvement of thermal conductivity for PPS, platy ceramic filler Boron Nitride (BN) with a micrometer size and good thermal conductivity was chosen to be filler, to prepare PPS/BN composites through melt blending by a HAKKE mixer. It was found that BN was well dispersed in PPS matrix by microstructure view; The thermal conductivity of PPS/BN composites was remarkably improved as more and more BN was added. When 40wt% BN was added, the thermal conductivity of PPS/BN composites reached 1.21W/ (m·k), 4.5 times higher than PPS resin.PPS/BN composites kept good electric insulating property while thermal conductivity was improved. Compared to PPS resin, the volume resistivity of PPS/BN composites decreased only one order of magnitude reaching 1017?·cm; Willbull distribution analysis showed that the dielectric strength decreased compared to PPS resin when relatively small amount of BN (10wt %) was added, when the content of BN was 20wt%, the dielectric strength of PPS/BN composites was higher than PPS resin and reached the highest at 40wt% BN content; PPS/BN composites kept almost the same dielectric constant and loss constant in a temperature scope 20℃-180℃and AC current frequency scope 103Hz-106Hz.To make further improvement on the thermal conductivity of PPS resin, graphitizing multiwall carbon nanotube(GCNTS) with large length-diameter ratio , high purity and high thermal conductivity was chosen to coordinate with BN , preparing hybrid PPS/BN/GCNTS composites. GCNTS and BN showed good coordination performance. Compared to PPS/BN composites with 40wt% content, the thermal conductivity of PPS/BN/GCNTS composites was higher with GCNTS content more than 3wt% and reached highest (1.585W/(m·k)) when 7wt% GCNTS was added. By SEM micrograph, it was found that BN is well dispersed in PPS matrix and GCNTS is well dispersed at the interface of BN-BN. GCNTS is like the bridge of BN-BN; A electric percolation reached when GCNTS content was 1-3wt% in the dielectric properties test, the PPS/BN/GCNTS changed to conductor from insulating material .According to toughening modification of general PPS resin, we chose a thermoplastic elastomer SEBS-g-MAH to blend with PPS resin. By melt blending, PPS/SEBS-g-MAH blends were prepared. Compared to PPS resin, PPS/SEBS-g-MAH blends have better ductibility. The elongation at break and izod impact strength of PPS/SEBS-g-MAH blends increased as more SEBS-g-MAH was added. When the SEBS-g-MAH content was 30wt%, the highest elongation at break reached 23.7% and the highest impact strength was 8.1kJ/m2, which was 10 times and 2.5 times from PPS resin respectively. Rheology test showed that the elastic modulus (G'), loss modulus (G'') and dynamic viscosity (|...