Effects of poly(L-lactide-e-caprolactone) and magnesium hydroxide additives on physico-mechanical properties and degradation of poly(L-lactic acid)

Background: Biodegradable poly(L-lactic acid) (PLLA) is one of the most widely used polymer in biomedical devices, but it still has limitations such as inherent brittleness and acidic degradation products. In this work, PLLA blends with poly(L-lactide-e-caprolactone) (PLCL) and Mg(OH)₂ were prepared by the thermal processing to improve their physico-mechanical and thermal properties. In addition, the neutralizing effect of Mg(OH)₂ was evaluated by degradation study. Results: The elongation of PLLA remarkably increased from 3 to 164.4 % and the glass transition temperature (T_g) of PLLA was slightly reduced from 61 to 52 °C by adding PLCL additive. Mg(OH)₂ in polymeric matrix not only improved the molecular weight reduction and mechanical strength of PLLA, but also neutralized the acidic byproducts generated during polyester degradation. Conclusions: Therefore, the results demonstrated that the presence of PLCL and Mg(OH)₂ additives in PLLA matrix could prevent the thermal decomposition and control degradation behavior of polyester.