| Abstract: | Two series of aromatic-aliphatic random copolyesters (PEBTOXS) with diverse diol ratios have been synthesizedby direct melting polycondensation. Two kinds of diols (glycol (EG) and 1,4-butanediol (BD)) are used in combination inorder to adjust crystallization and tensile properties, and three kinds of diacids (dimethyl terephthalate (DMT), diethyloxalate (DEOX), and sebacic acid (SA)) are involved. IH-NMR spectra quantify both composition and structure, and showthat the final contents in copolyesters appropriate to the feed ratio. Average sequence lengths of six polyester units arecalculated based on the analyses of 1H-NMR spectra and copolyester structure. The results reveal that the average sequencelengths of sebacate related units increase with the increasing content of sebacic acid in copolyesters, while those of oxalaterelated units show a slight rise. Decreases of average sequence length are found for all terephthalate units, which may bebecause of the restriction of rigid aromatic units in reactions. |
