Study On Morphologies, Structures And Properties Of Polyphenylenesulfide Composites

Polyphenylenesulfide(PPS) is an attractive matrix material because of its excellent mechanical properties, high temperature durability, chemical resistance, and easy processing. However, the most serious shortcoming of this material is its very low impact strength . In this work, toughening and reinforcing modification of PPS by blending with rigid inorganic nano-CaCO₃ particles, glass beads, glass fibres and an elastomer polyethylene-octene copolymer(POE) were investigated. The mechanical properties, microstructure and the relationship between them were also carefully studied. A lot of valuable information was obtained that can be used for development of PPS. The main works and conclusions were listed as following: 1. Composites of polyphenylene sulfide reinforced with calcium carbonate nanoparticles were prepared by melt mixing in an extruder palletizer. The mechanical and rheological properties, also the distribution and morphology of PPS/ nano-CaCO₃ are researched. The result shows that the average particle size of the CaCO₃ nanoparticles was about 56nm( approx ), tensile tests showed that the tensile strength was 83.73Mpa when the addition was 10 wt%, impact stress was 74.13 kJ/m2 when the addition was 5wt%. The rheology of the composition of PPS/nano-CaCO₃ of various proportions has been conducted with the high-pressure capillary, the result shows that when the component of nano-CaCO₃ is at the low level, the viscosity of the system is not changed greatly and the rheologcial behavior of the composition system is found to be falsely plastical and thus satisfy the power model. 2. The elastomer POE influences the mechanical properties of PPS/POE composite. The impact strength of the PPS/POE composite were increased nonlinearly almost as the contentration of POE increased. The increase in toughness of the PPS/POE composite is attributed to its large amount of plastic deformation of POE particles. The impact strength of the PPS blend with POE(30%) is 16.78 KJ/m2, much higher than that of pure PPS(6.34 KJ/m2). At the same time, the tensile strength of the PPS/POE decreases largely. When the content of POE is about 10%,the impact strength is over 10 KJ/m2 and the tensile strength remains about 60MPa.The morphological structures of the PPS/POE composites shows that the increase in toughness of the PPS/POE composite is attributed to its large amount of plastic deformation of POE particles. 3. Dynamic rheology behavior of PPS/POE was first studied. The results indicated dynamic rheology behavior of composite related to content of POE. The dynamic storage modulus (G′ ) and the loss modulus(G″)of the PPS/POE composite were increased nonlinearly as the content of POE increased at 290℃. The viscosity of PPS/POE were increased with the content of POE increasing.At 290℃ temperature, the viscosity of PPS/POE decreased with the inceasing of shear rate, and didn`t change significantly at last. The deformation of POE particles led to the viscosity of PPS/POE(20%) to the top and it is hard to use in the industry. 4. Three-phase composites were obtained by blending PPS with elastomer and CaCO3 particles. The influences of nano-CaCO3 and POE on the mechanical properties of PPS composites were investigated. A study of phase morphology of PPS/POE/nano-CaCO3 composites by means of scanning electron microscopy (SEM) showed that the contents of filler and elastomer are 3% and 5% are better. The impact strength of PPS/POE/nano-CaCO3 was 28.87 KJ/m2. 5. At the same conditions, the tensile strength and the Izod impact strength of the PPS filled with small glass beads are higher than those of the PPS filled with bigger glass beads. The influence of the surface treatment of glass bead on the mechanical properties of PPS/GB were studied. The Izod impact strength of the PPS blend with 40% glass beads treated with silane coupling agent are 43.78 KJ/m2, higher than those of the untreated which is 31.07 KJ/m2. the tensile strength was 83.73Mpa, higher than that of the untreated which is 54.71Mpa .6. At the test conditions, the composites dispersed with an appropriate content of glass beads particles possessed excellent wear resistance. When the glass beads diameter becomes smaller, the coefficient of friction decrease. The tribological properties depended on the firmly bonded, thin and uniform transfer film. Adhension transfer and deformation fatigue were the main mechanisms of PPS/GB composites during abrasive wear.