Fabrication of poly(lactic acid) films with resveratrol and the diffusion of resveratrol into ethanol

摘要

Poly(94% L-lactic acid) (PLA) films containing 0, 1, and 3 wt % resveratrol (PR0, PR1, and PR3) were extruded in a pilot-plant scale blown-extrusion machine. Yellow-colored PLA films with reduced crystallinity were obtained, and the films absorbed UV-visible light at 350-200 nm. The diffusion kinetics of resveratrol into ethanol at 9, 23, 33, and 43°C displayed Fick's behavior, and diffusion coefficients between 10~(-13) and 10~(-10) cm 2/s were obtained. According to the Arrhenius equation, the energy of activation for the diffusion of resveratrol from PR1 and PR3 films was 175 and 177 kJ/mol, respectively. The temperature of diffusion had a stronger effect on the reduction of the weight average molecular weight of PLA than the processing conditions and the contact time with ethanol. However, diffusion of resveratrol was not affected by the degradation of PLA.