Chain structure and thermal behavior of reactive blends of poly(ethylene terephthalate)/poly(butylene terephthalate) by addition of 2,2′-(1,4-phenyl) bisoxazoline

The chain structure and thermal behavior of reactive blends of poly(ethylene terephthalate) (PET) with poly(butylene terephthalate) (PBT) by 2,2′-(1,4-phenyl) bisoxazoline (PBO) were studied in detail. The 13C NMR results indicate that the chain structures of the reactive blends are significantly affected by the mixing time and temperature owing to transesterification. The transesterification can be accelerated in the presence of PBO, especially when the mixing temperature is above 270°C. As a consequence, the chain structure, and in turn, the crystallization behavior both from the glassy and melt states and the melting behavior are significantly changed.