Sequence analysis of poly (ethylene/1,4-cyclohexanedimethylene terephthalate) copolymer using 1H and 13C NMR

The triad-level sequence analysis of poly(ethylene/1,4-cyclohexanedimethylene terephthalate) copolymer was reported in a solvent system of o-chlorophenol/deuterated chloroform mixture (50/50 v/v) at 80degreesC using 600 MHz H-1 NMR. The well-resolved alcoholic CH2 proton peak of the glycol units was observed, which made the detailed sequence analysis possible. The peaks of the cis- and trans-forms of the 1,4-cyclohexanedimethylene glycol units were split into the triad sequence in the chain and could be assigned by a comparison of the spectra with those of homopolymers and by an additional two-dimensional heteronuclear multiple bond correlation observation. The triad sequence distributions centered on 1,4-cyclohexanedimethylene glycol units were determined, which was independent of the cis- and transforms of the units and controlled according to Bernoullian statistics. (C) 2003 Elsevier Science Ltd. All rights reserved.