The crystallization rate of poly(ethylene terephthalate) accelerated by co[poly(butylene terephthalate-p-oxybenzoate)] copolyesters

Poly(ethylene terephthalate) (PET) was blended with three different kinds o f co[poly(butylene terephthalate-p-oxybenzoate)] copolyesters, designated B 28, B46, and B64, with the level of copolyester varying from 1 to 15 wt %. All samples were prepared by solution blending in a 60/40 by weight phenol/ tetrachloroethane solvent at 50 degrees C. The crystallization behavior of samples was then studied via differential scanning calorimetry. The results indicate that these three copolyesters accelerate the crystallization rate of PET in a manner similar to that of a nucleating agent. The acceleration of PET crystallization rate was most pronounced in the PET/B28 blends with a maximum level at 10 wt % of B28. The melting temperatures for the blends are comparable with that of pure PET. The observed changes in crystallizat ion behavior are explained by the effect of the physical state of the copol yester during PET crystallization as well as the amount of copolyester in t he blends. (C) 2000 John Wiley & Sons, Inc.