Nonisothermal crystallization studies of PBT/ZnO compounds

Compounds of poly(butylene terephthalate) (PBT) and zinc oxide (ZnO) with filler content between 1 and 10% were prepared in a laboratory internal mixer. The processing parameters did not damage PBT thermal stability or its molecular weight as evidenced by torque rheology. The melt crystallization of PBT/ZnO compounds was investigated by differential scanning calorimetry and their morphology by scanning electron microscopy and optical microscopy. From morphological analyses, ZnO particles are well dispersed in PBT matrix, which crystallizes in typical spherulites. The melt crystallization temperatures and maximum melt crystallization rates are almost unaffected by the filler. Equally the overall crystallinity did not show any dependence on the filler content or the cooling rate. Mo's model was found to be suitable for a description of the melt crystallization kinetics, while Ozawa model turned out to be inadequate.