Thermal and crystallization behavior of alloys of polyphenylene sulfide and high-density polyethylene

The thermal and crystallization behavior of alloys of two semicrystalline thermoplastics, namely, polyphenylene sulfide (PPS) and high-density polyethylene (HDPE) were studied by differential scanning calorimetry (DSC). The presence of a second component in the alloy was found to influence the nonisothermal crystallization process of both the component polymers. The crystallization temperature of PPS in the DSC cooling scan is significantly affected, whereas there is little variation in case of HDPE in the composition range studied. The morphological changes observed in both PPS and HDPE are similar. These include larger crystallite size, a narrower crystallite size distribution, and a lower degree of crystallinity in the alloys as compared to the homopolymers. The isothermal crystallization of the component polymers in the alloys is significantly different from that of the homopolymer. The composition dependence of the overall rate of isothermal crystallization is explained in terms of the competing processes of nucleation and crystal growth. The results show that blending of a high melting polymer with a low melting polymer accelerates the crystallization of the high melting polymer, even at low levels of about 10% of the lower melting component