A STUDY ON SEQUENCE DISTRIBUTION IN PET/PHB COPOLYESTERS BY 1H AND 13C-NMR
用1H-和13C-NMR方法研究聚对苯二甲酸乙二酯/聚一氧基苯甲酸酯共聚酯的序列分布

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.