High resolution 1H and 13C-NMR spectra for PET/30PHB and PET/6 PHB copolyes-ters in solution have been measured. The 13C absorptions were assigned by the help of the determination of quaternary carbon absorption with INEPT and partially relaxed FT techniques. Our method previously proposed was applied to characterize the sequence distribution of the copolyesters. The degree of randomness Bq for PET/30PHB and PET/60PHB were found to be 0.87 and 0.81 respectively

the values which are both less than unity for the com-pletely random copolyester. In addition

lt has been pointed out to be improper to judge whe-ther the chain structure of PET/PHB copolyesters is random by comparing their melting po-ints with that predicted by Flory's equation

as some researchers have done.