Stuy On Machanical Properties And Dielectric Properties Of PPS/GF Composites With Commingled Yarn Structure

Polyphenylene sulfide(PPS)is a kind of polymer material with repeated unit rigid benzene rings and sulfur atoms as the ma in chain.Because of the special structure,PPS is determined with high electrical insulation(conductivit y is 10-10 at a frequency of 105 Hz and at temperature of 25 ℃),High temperature resistance(long-term use temperature of 220 ℃),chemical resistance(does not contain any solvent below 200 ℃),easy processing and other advantages,which has been widely applied in aerospace,automotive,petrochemical,electronic and other areas.However,the mechanical properties of PPS are not high,which severely restricts the use of PPS as a secondary load bearing and bearing component.It has important theoretical and practical value to study the effect of continuous glass fiber(GF)reinforcement on improving the mechanical properties of PPS.Use-designed GF content of 60 wt.%,70 wt.%,80 wt.% three mixed-blend yarn structure PPS/GF;Continuous fiber GF reinforced PPS composite plates have been fabricated by molding preparation,By analyzing the effect of molding parameters(temperature,time)on the thickness,void content and PPS resin content of plates,The influencing factors of the molding parameters on the tensile and bending properties of the PP S/GF composite plates were analyzed essentially.The optimum process parameters for different GF content composite boards.The dynamic thermomechanical properties of the PPS and PPS/GF composite plates were obtained by dynamic mechanical properties(DMA).DMA gave a Glass transition te mperature(Tg)between 108 ℃ and 118 ℃.PPS and PPS/GF composite plates have a higher storage modulus below Tg;The storage modulus has a decreasing range of 1000 MPa to 1500 MPa in the Tg around and the PPS/GF composite plates still has a high storage modulus.By testing the thermo mechanical properties of PPS and PPS/GF composite plates at different frequencies,based on the Arrhenius equation,the activation energy(Ea)of PPS and PPS/GF composite plates near Tg was calculated.The increase of GF content gradually decreased Ea.The stress relaxation behaviors of PPS and PPS/GF composite plates at different temperatures were studied.Under the same stress,the stress relaxation of the composite plates was higher with the increase of temperature;the general Maxwell model was used to simulate the stress relaxation at 110 ℃.The stress relaxation is fitted to obtain a long time constant temperature relaxation process;the stress relaxation of the PPS and PPS/GF composite plates is fitted by time temperature equivalence principle,and the material can be predicted for a long time(more than 2 years)stress changes over time.In order to study the influence of the interface between PPS and GF on the dielectric properties of the composite plates,a dielectric spectro meter was used to test the dielectric properties of the PPS and PPS/GF composite plates.In the frequency sweep,with the increase of GF content,while the dielectric constant and the dielectric loss of the PPS/GF composite material plate is significantly higher than that of PPS,and the existence of the two-phase interface can improve the dielectric propertiesof composites.In the temperature sweep,dielectric constant of PPS/GF composite platesis higher than PPS.