Composition,thermal properties,and biodegradability of a new biodegradable aliphatic/aromatic copolyester |
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Authors: | Ling Han Guixiang Zhu Wei Zhang Wei Chen |
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Affiliation: | 1. College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China;2. Sinopec Beijing Research Institute of Chemical Industry, China Petroleum & Chemical Corporation, Beijing 100013, China |
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Abstract: | A series of new aliphatic/aromatic copolyesters poly(hexylene terephthalate‐co‐hexylene adipate) (PHTA)] were synthesized on the bases of 1,6‐hexanediol, adipic acid, and dimethyl terephthalate and characterized by gel permeation chromatography, 1H‐NMR, wide‐angle X‐ray diffraction (WAXD), differential scanning calorimetry (DSC), and compost testing. 1H‐NMR results show that the compositions of the copolyesters were in accordance with the feed molar ratios. The WAXD patterns indicated that the crystal structures of the PHTA copolyesters were determined by the dominant crystal units, and the copolyesters became less crystallizable, even amorphous, with increasing comonomer content. The DSC curves showed that the glass‐transition temperatures (Tg′s) of the PHTA copolyesters decreased linearly, and both the melting temperature (Tm) and heat of fusion decreased first and then increased with increasing hexylene adipate unit content. Under compost conditions, PHTA copolyesters with less than 60 mol % aromatic units were biodegradable. Particularly, compared with the copolyester poly(butylene terephthalate‐co‐butylene adipate), the PHTA copolyester with the same aliphatic/aromatic composition possessed a lower Tg and Tm and better biodegradability. Additionally, the biodegradability of the copolyesters could be predicted by the number‐average sequence length of aromatic units, Tg, and the temperature difference between Tm and the temperature at which biodegradation took place. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 |
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Keywords: | biodegradable crystal structures thermal properties |
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