CRYSTALLIZATION KINETICS OF POLY(ETHYLENE-TEREPHTHALATE) IN COMPOSITIONS CONTAINING NATURALLY FUNCTIONALIZED TRIGLYCERIDE OIL

The crystallization of poly(ethylene terephthalate) (PET) in blends with naturally functionalized triglyceride oils and their networks has been investigated. Crystallization kinetics of PET in the presence of small amounts of castor oil is improved, both in cooling from the melt state, and in heating from the glassy state. In conjunction with the nucleating agent sodium benzoate, either chemically bonded to castor oil or as a simple mixture, even greater enhancements of crystallization are observed. The PET crystallinity in semi-IPNs and blends of low to intermediate castor oil-HMDI polyurethane content are higher than that of neat PET (on a per gram of PET basis). Crystallinity in compositions with a high triglyceride oil network content is greatly affected by the presence of the network, with large melting point depressions, and loss in overall crystallinity. In cases where the triglyceride oil network is completely formed in a miscible melt with PET, the PET is unable to crystallize on cooling, resulting in amorphous semi-IPNs. Plasticization due to the oil, nucleation from added agents, bond interchange reactions between the oil and the PET, overall chemical composition, and the presence of a triglyceride oil network are found to have a controlling influence over the type and extent of PET crystallinity in the compositions.