Abstract: | Copolyesters made from Poly(butylene terephthalate) (PBT) and p‐acetoxybenzoic acid (PAB) have been examined in solution by proton nuclear magnetic resonance (NMR) spectroscopy. Proton NMR spectra of solutions have shown that the sequence distribution for POB/PBT copolyesters can be described in terms of a probability model in which POB (p‐oxybenzoate) has a chance that is almost random of being bonded to another POB in the copolyesters, with POB content ranging from 20 to 40 mol %. From the experimental data, we can predict that the higher the content of POB in copolyester is, the larger the deviation from randomness of sequence distribution is. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 949–954, 2000 |