| Poly(phenylene sulfide)(PPS) is a semi-crystalline engineering thermoplastic with outstanding properties, such as good chemical resistance, high temperature resistance, good physical and mechanical properties, and good dimensional stability and so on. It is widely used in many fields such as aerospace and electrical appliances. However, the brittleness and low elongation at break limit its further applications. Therefore, it is of great significance to study the reinforcement and toughening of the PPS and its composites.In this paper, several composites such as poly(phenylene sulfide)/carbon fiber composites (PPS/CF), poly(phenylene sulfide)/ elastomers composites (PPS/SBS and PPS/SEBS-g-MAH), poly(phenylene sulfide)/inorganic nano-particles composites (PPS/nano-SiO2 and PPS/nano-Fe3O4), and poly(phenylene sulfide)/nylon 6/epoxy resin composites (PPS/PA6/ER) were prepared directly via melting blending. The surface and fracture surface morphologies, crystallization behavior, melt-flowing properties, electrical, heat resistance and mechanical properties of PPS composites were studied by transmission electron microscope (TEM), scanning electron microscope (SEM), X-ray diffractometer (XRD), rheometer, differential scanning calorimeter (DSC), broadband dielectric constant detector, simultaneous thermal analyzer(STA), dynamic mechanic thermal analyzer (DMTA). Moreover the effects of contents and surface treatments as well as morphology of fillers on the properties of the composites were also investigated.(1) Preparation, Structure and Properties of PPS/CF compositesPPS/CF composites were prepared by melt-blending. The SEM results showed that CF were well dispersed in PPS phase, and the fracture morphology of the composites was rough, indicating that the CF has a good compatibility with the matrix phase PPS. The results of mechanical measurements showed that the tensile strength, flexural strength and impact strength of the PPS/CF composites were greatly improved,and when the CF weight fraction were 18wt~20wt%,the tensile strength and the flexural strength of the PPS/CF composites was 117.8 MPa and178.1 MPa,as well as the impact strength was up to 38.7 kJ/m2. The DSC and XRD results showed that the presence of CF accelerated the crystallization rate of PPS matrix and also reduced its crystallinity, but did not affect the crystal type of PPS, CF played a role of heterogeneous nucleating agnet in the composites system. The electrical properties tests results showed that the PPS/CF composites had higher volume conductivity of 3.0×10-3 S/m at room temperature and hogher permittivity than those of neat PPS. The addition of CF enhanced the heat resistance property of the matrix PPS, and also enhanced the dynamic modulus and the glass transition temperature of PPS/CF composites.(2) Preparation, Structure and Properties of PPS-elastomers BlendsThe two elastomers SBS and SEBS-g-MAH were chosen to improve the toughness of PPS, and the blends were prepared by melt-blending. The fracture morphology showed that the elastomers were well dispersed in the PPS matrix, and SEBS-g-MAH was much more compatible with the PPS matrix than that of SBS. The addition of SBS and SEBS-g-MAH improved the impact strength of PPS and up to30.5 kJ/m2and 34.4 kJ/m2,which compared to the neat PPS increased by 33% and 50%, but reduced the tensile strength and the flexural strength because of lower modulus of elastomer phases. The PPS-elastomers blends were easier to be thermally degraded and be deformed than neat PPS, which were proved by the results from STA and vicat soft temperature testing. The PPS-elastomers blends have a higher glass transition temperature and a lower crystallinity than those of the neat PPS. The dielectrical properties of matrix PPS were affected by the addition of the elastomers. By comparing the modifying effects of SBS and SEBS-g-MAH, the results showed that the impact strength of the PPS/SEBS-g-MAH blend was higher than the PPS/SBS blend, but addition of the SEBS-g-MAH had a little negative effects on the other properties of the PPS matrix.(3) Preparation, Structure and Properties of PPS/ nano-particles Composites PPS/ nano-SiO2 composites and PPS/ nano-Fe3O4 composites were prepared by melt-blending and the surface-treated nano-particles were well dispersed in the PPS matrix. The SEM images also confirmed that the surface-treated nano-particles had a better adherence to the PPS component than the untreated particles. The mechanical properties tests results showed that the presence of nano-SiO2 and nano-Fe3O4 particles improved both the impact strength and the tensile strength as well as flexural strength.The tensile strength and the flexural strength of PPS/ nano-Fe3O4 composites was up to 56.53 MPa and120.14 MPa, and those of PPS/ nano-SiO2 composites was 53.24 MPa and 97.27 MPa.The DSC results showed that the nano-particles accelerated crystallization rate but reduced crystallinity of the PPS matrix. The PPS/nano-particles composites showed higher temperature resistance and better electrical properties than those of the neat PPS. By comparing the properties of PPS/nano- SiO2 and PPS/ nano-Fe3O4, it was found that the PPS/ nano-Fe3O4 composites showed better properties than those of PPS/nano- SiO2 composites in the case of identical particles contents,the impact strength of the PPS/ nano-Fe3O4 composites and PPS/ nano-SiO2 (treated) composites were 22.98 kJ/m2and15.91 kJ/m2.(4) Preparation, Structure and Properties of PPS/PA6/ER Ternary BlendsPPS/PA6/ER ternary blends were prepared by melt-blending. In the PPS/PA6/ER composites, the ER was used to enhance the interfacial strength between the PA6 and the PPS matrix. The properties of the blends were investigated by SEM, XRD, DSC, STA and DMA. The results showed that the best mass proportion of PPS/PA6/ER was 100/10/10, and the The tensile strength and the flexural strength of the blend was 83.10 MPa and 131.09 MPa,the impact strength was 38.79 kJ/m2. And the addition of PA6 and ER also had influences on crystallizition , high temperature resistance and dielectrical properties of the PPS blends. |
PDF Full Text Request