Ethylene Glycol Terephthalate/Diethylene Glycol Terephthalate Copolymer

II. Determination of Copolymer Composition by High Resolution NMR Spectroscopy

Abstract

The copolymer composition of ethylene glycol terephthalate/diethylene glycol terephthalate [PET/(DEG) T] was determined by high resolution NMR spectra of the copolymer in o-chlorophenol.
1) The composition of PET/(DEG) T can be determined from the intensity of a signal at 3.8ppm relative to that at 4.5ppm, both being assignable to two sorts of methylene protons.
2) The sequence of monomer units is discussed on the basis of the phenylene peaks of PET/(DEG) T by Bovey and coworker's method. The distribution of monomer-unit sequences deviates from that expected from the equal reactivities of the functional groups.