Effect of strain-induced molecular ordering on mechanical performance and barrier properties of polylactide nanocomposites

Plastic deformation of polylactide has been known as a self-reinforcement alternative to improve mechanical and barrier properties. In this study, the structural evolution was investigated during a hot-drawing process, at different initial strain rates and temperatures above T-g of polylactide. The drawing process at T-g +10 degrees C, led to the formation of an intermediate molecular ordering, between the crystalline and amorphous phases. A lower fraction of this mesomorphic phase was found to develop with the addition of nanoparticles. An increase in the stretching temperature to T-g +30 degrees C, caused an improvement of the crystallization kinetics, compared to that of thermally activated crystallization. A strain hardening behavior was observed in the presence of mesophase during a stretching process of the hot-drawn films at room temperature. Permeability was discerned to its basic components, diffusivity, and solubility coefficients. The matrix degradation influenced the permeability components. The diffusivity decreases in the presence of the impermeable matters. (c) 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017, 55, 1865-1876