Poly(L-lactic acid) Modified by Magnesium Phenylmalonate: Thermal Behavior, Processing Fluidity, and Mechanical Properties

Abstract

This study presents the role of the magnesium phenylmalonate (MgPA) in the thermal behavior, fluidity, and mechanical properties of Poly(L-lactic acid) (PLLA). The results from non-isothermal crystallization investigation showed that the presence of MgPA as a heterogeneous nucleating agent facilitated the crystallization of PLLA in cooling. Additionally, the non-isothermal crystallization behavior of PLLA/MgPA was affected significantly by MgPA concentration, the cooling rate, and the final melting temperature. Melting behavior of PLLA/MgPA under different testing conditions further confirmed the crystallization accelerating effect of MgPA for PLLA, and the double melting peaks of PLLA/MgPA system mainly assigned to the melting-recrystallization mechanism. A decrease of the onset decomposition temperature indicated that the incorporation of MgPA reduced the thermal stability of PLLA, but the effect of MgPA on the thermal decomposition profile of PLLA is negligible. Compared to the primary PLLA, the addition of MgPA could improve significantly the fluidity of the PLLA, and the fluidity became better with increasing of MgPA concentration in PLLA matrix. MgPA of 0.2 wt.% to 2 wt.% could make the tensile strength of PLLA increase, however, a continuous drop in elongation at break was also observed.

DOI: http://dx.doi.org/10.5755/j01.ms.24.1.17947