Polyethylene terephthalate ethylene, used as PET substitute, comprises ethylene nitroterephthalate units

摘要

Dimethyl terephthalate (DMT) and dimethyl nitroterephthalate (DMNT) are transesterified with ethylene glycol and this is followed by condensation polymerization to form a polyethylene terephthalate (PET) copolymer containing ethylene nitroterephthalate units. PET-ethylene nitroterephthalate copolymers are prepared by a method comprising the following steps: (1) transesterification of DMT and DMNT with ethylene glycol at 190[deg]C under a nitrogen atmosphere; and (2) condensation polymerization at 220-270[deg]C under vacuum, in the presence of titanium tetrabutoxide (TBT) catalyst. The copolymers comprise 5-100 mol.% ethylene nitroterephthalate units having a number average molecular weight (Mn) of 4200-16300, a weight average molecular weight (Mw) of 10400-62200, a glass transition temperature (Tg) of 82-88[deg]C, a melting point of 180-248[deg]C and a high thermal stability.