New insights into transreaction mechanism between poly (ethylene terephthalate) and bisphenol A polycarbonate in melt

Abstract

In the present study, the macromolecular chain composition of copolymers prepared by the reactive blending of poly(ethylene terephthalate) (PET) and bisphenol A polycarbonate (PC) in the presence of Ti(OBu)₄ catalyst was tested using ¹H and ¹³C NMR spectroscopy. The NMR spectra were meticulously analyzed across all regions, revealing unexpected results that provide new insights into the transreaction mechanism occurring between these two polymers in the melt phase. It was found that only two primary reactions occurred: the formation of a bisphenol A terephthalate bond accompanied by the release of ethylene carbonate and the formation of an aliphatic–aromatic ether bond with the release of CO₂. The release of ethylene carbonate during the PET-PC blending led to a loss of ethylene glycol (EG). The kinetics of EG loss and ether bond formation were examined. A new transreaction mechanism for PET-PC reactive blending is proposed. © 2024 Society of Chemical Industry.