A NMR spectroscopic method was used for the determination of the diol contents such as propylene glycol and polyethylene glycol in copolyesters. The quantitative analysis of copolyester compositions was made by comparing the areas of the resonance peaks of the characteristic groups in the spectra. The compositions of the copolyesters made from dimethyl terephthalate with ethylene glycol and propylene glycol, containing whole range of propylene glycol, were determined from the ratios of phenylene vs. methyl protons. The compositions of the copolyesters made from dimethyl terephthalate with ethylene glycol and polyethylene glycol-400, containing less than 30 mole % of polyethylene glycol-400, could be determined from the differences in chemical shifts of ether- and ester-linked methylene protons of the diols, In order to confirm these results, the gas chrosmatographic method was used. The result stherefrom correspond to those proposed by NMR method.

핵자기 공명분광법(NMR)을 이용하여 copolyester중의 propylene glycol과 polyethylene glycol등 diol unit의 함량을 조사하였다. Copolyester의 조성은 NMR spectra에 나타나는 특성 group의 proton에 의한 공명 peak의 면적을 비교하여 정량하였다. Dimethyl terephthalate(DMT)와 ethylene glycol (EG) 및 propylene glycol (PG)로 합성된 copolyester는 phenylene proton과 methyl proton에 의해 분석하였고, DMT와 EG 및 polyethylene glycol-400 (PEG-400)으로 합성된 copolyester는 ether 결합에 이웃한 methylene proton과 ester 결합에 이웃한 methylene proton의 chemical shift가 서로 다른 것을 이용하여 분석하였다. 이 결과를 확인하기 위해 gas chromatography를 이용하여 분석한 결과와 비교하였다.

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