Is It Possible to Extend the Coleman−Fox Method for Polymer Sequence Determination by NMR to Copolycondensates?

Abstract

A new theory is presented for the interpretation of NMR spectra of copolycondensates, with special attention to those obtained by melt mixing of two macromolecular chains (reactive blending). The repeat unit is split into two parts, referred to as half-monomers. The present theory gives a highly accurate description of the changes in the sequence distribution during the reactive blending reaction, since the effect of the first and second neighbors along the macromolecular backbone (half-monomer penultimate effect) is explicitly considered. The theoretical predictions are compared with experimental data taken from the literature and, more specifically, NMR data concerning five copolymer systems, namely, a copolymer obtained by reactive blending of poly(ethylene terephthalate) and poly(ethylene adipate), an almost alternating copolymer with units of ether-sulfone and ether-ketone, a copolymer derived from 6-methyl-2,5-morpholinedione, and two copolymers obtained by reactive blending of poly(butylene terephthalate) with poly(bisphenolA carbonate) and Nylon6, respectively.