(2‐Hydroxy isobutyric) acid containing poly(glycolic acid): Structure–properties relationship |
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| Authors: | Michelina Soccio Nadia Lotti Lara Finelli Massimo Gazzano Andrea Munari |
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| Institution: | 1. Dipartimento di Chimica Applicata e Scienza dei Materiali, Università di Bologna, Via Terracini 28, 40131 Bologna, Italy;2. Istituto per la Sintesi Organica e la Fotoreattività, CNR, Via Selmi 2, 40126 Bologna, Italy |
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| Abstract: | Poly(glycolic acid) (PGA) and a series of novel random copolymers of PGA containing 2‐hydroxyisobutyrric acid (PGAPHIB) (HIB unit content from 1.5 to 7.4 mol %) were synthesized and characterized in terms of chemical structure and molecular weight. Afterward, the polyesters were examined by thermogravimetric analysis, differential scanning calorimetry, and X‐ray diffraction techniques. The copolymers, which displayed a better thermal stability than PGA, at room temperature appeared as semicrystalline materials: the main effect of copolymerization was a lowering in the amount of crystallinity and a decrease of the melting temperature with respect to homopolymer PGA. Baur's equation described well the Tm‐composition data. X‐ray diffraction measurements allowed the identification of the PGA crystalline structure in all cases. After melt quenching, semicrystalline samples were obtained with the exception of PGAPHIB7.4 copolymer. The introduction of HIB units decreased the crystallization rate compared with pure PGA. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1901–1910, 2010 |
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| Keywords: | copolymerization 2‐hydroxyisobutyric acid poly(glycolic acid) thermal properties WAXS |
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