Composition and Microstructure of a Copolyester Formed in the Melt-Mixing of Poly(Ethylene-Terephthalate) and Poly(Ethylene Truxillate)

Abstract: This study shows that is possible to determine the composition and microstructure of the copolyester formed in the melt-mixing process of poly(ethylene truxillate)a) (PETx) and poly-(ethylene terephthalate) (PET), by applying a novel method of statistical modeling of mass spectra of copolymers. The peak intensities of molecular ions appearing in the fast atom bombardment mass spectrum of the melt-mixed equimolar mixture of PETx and PET were found to reflect the relative amounts of oligomers present in the sample and to be directly related to the microstructure of the copolymer formed. The statistical analysis of copolymers allows one to generate a number of different theoretical mass spectra that can be fitted with the experimental mass spectrum data, thus determining the most likely copolymer composition.