Characterization and thermal degradation of poly(d,l‐lactide‐co‐glycolide) composites with nanofillers |
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Authors: | Jordana Palacios Carmen Albano Gema González Reina Verónica Castillo Arquímedes Karam María Covis |
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Affiliation: | 1. Laboratorio de Polímeros, Centro de Química, Instituto Venezolano de Investigaciones Científicas, Caracas 1020‐A, Venezuela;2. Escuela de Ingeniería Química, Facultad de Ingeniería, Laboratorio de Polímeros, Universidad Central de Venezuela, Caracas, Venezuela;3. Laboratorio de Materiales, Centro de Ingeniería de Materiales y Nanotecnología, Instituto Venezolano de Investigaciones Científicas, Caracas 1020‐A, Venezuela |
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Abstract: | Chemical and thermal characterization of poly(d ,l ‐lactide‐co‐glycolide) (PLGA) composites filled with hydroxyapatite (HA) or carbon nanotubes (CNT) were evaluated by infrared spectroscopy, differential scanning calorimetry, thermogravimetry, and dynamic–mechanical–thermal analysis. The morphology and distribution of the nanoparticles were studied by transmission electron microscopy. The composites were prepared by solvent casting using 30% HA or 1, 3, and 5% of pristine and functionalized CNT as nanoparticles and PLGA 75:25 and PLGA 50:50 as copolymer matrix. The Coats–Redfern and E2 function methodologies were used to calculate the reaction order and the activation energy (Ea) of the thermal degradation process. It was found that the addition of nanoparticles increased the glass transition temperature (Tg) of the composites. Also, higher degradation temperatures and Ea values were obtained for PLGA–HA composites and compared with the neat copolymer, and the opposite behavior was exhibited by PLGA–CNT composites. The thermal and mechanical properties were highly dependent on the morphology and dispersion of the filler. The functionalization process of CNT promoted, to some extent, a better distribution and dispersion of CNT into the matrix, and these composites exhibited a slight enhancement on storage modulus. On the other hand, PLGA–HA composites showed a good dispersion but no improvement on the storage modulus below Tg. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers |
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