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PLLA-HA vs. PLGA-HA characterization and comparative analysis

Abstract:

The chemical, thermal, thermo-mechanical, and morphology properties of poly(L-lactide) (PLLA) and poly(D,L Lactide-co-glycolide) (PLGA) composites with 30% hydroxyapatite (HA) were evaluated. The composites were prepared employing the solvent casting technique. The degradation kinetic parameters were obtained using the Coats-Redfern integral method for the reaction order and the E 2 function methodology to calculate the activation energy (E a). The addition of HA to these polymers matrices increased their glass transition temperature. This was confirmed by differential scanning calorimetery and dynamic-mechanical-thermal analysis. Also, the presence of HA increased the crystallization temperature of PLLA, implying a nucleation effect. The PLLA-HA and PLGA-HA composites exhibited better thermal stability, higher decomposition temperature, and higher activation energy for the decomposition process than the neat polymers. Morphology and dispersion of the filler are highly responsible for the thermal and mechanical properties of the composites, the PLGA-HA composites showed a well dispersion but no improvement on storage modulus was found. On the other hand, the storage modulus (E′) of PLLA-HA was enhanced, with respect to the neat polymer, mainly at temperatures above the glass transition. © 2013 Society of Plastics Engineers.