Carbohydrate‐based copolyesters made from bicyclic acetalized galactaric acid |
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Authors: | C Lavilla A Alla A Martínez de Ilarduya E Benito M G García‐Martín J A Galbis S Muñoz‐Guerra |
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Institution: | 1. Departament d'Enginyeria Química, Universitat Politècnica de Catalunya, ETSEIB, Diagonal 647, 08028 Barcelona, Spain;2. Departamento de Química Orgánica y Farmacéutica, Universidad de Sevilla, Profesor García González 2, 41012 Sevilla, Spain |
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Abstract: | Mixtures of the dimethyl esters of adipic acid and 2,3:4,5‐di‐O‐methylene‐galactaric acid (Galx) were made to react in the melt with either 1,6‐hexanediol or 1,12‐dodecanediol to produce linear polycyclic copolyesters with aldarate unit contents varying from 10 up to 90 mole %. The copolyesters had weight–average molecular weights in the ~35,000–45,000 g mol?1 range and a random microstructure, and were thermally stable up to nearly 300 °C. They displayed Tg in the ‐50 to ‐7 °C range with values largely increasing with the content in galactarate units. All the copolyesters were semicrystalline with Tm between 20 and 90 °C but only those made from 1,12‐dodecanediol were able to crystallize from the melt at a crystallization rate that decreased as the contents in the two comonomers approached each other. Copolyesters containing minor amounts of galactarate units adopted the crystal structure characteristic of aliphatic polyesters but a new crystal polymorph was formed when the cyclic sugar units became the majority. Stress–strain parameters were sensitively affected by composition of the copolyesters with the mechanical behavior changing from flexible/ductile to stiff/brittle with the replacement of adipate units by the galactarate units. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 |
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Keywords: | polyesters renewable resources step‐growth polymerization |
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