Water Absorption and Hygrothermal Aging Behaviors of SEBS-g-MAH Toughened Poly(lactic acid)/Halloysite Nanocomposites

Poly(lactic acid)/halloysite nanoclay composites (PLA/HNC) containing maleic anhydride grafted styrene-ethylene/butylene-styrene (SEBS-g-MAH) were exposed to hygrothermal aging at three different temperatures, i.e., 30, 40 and 50°C. The analysis was focused on the water diffusion kinetics and physical changes induced by the hygrothermal degradation. The water absorption kinetics of the PLA/HNC composites at immersion temperature of 30 and 40°C conforms to Fick's law. The equilibrium water absorption (Mm ) and diffusion coefficient (D) values are dependent on the SEBS-g-MAH content and immersion temperatures. Hydrolytic chain scission provoked significant molecular weight reduction. Nevertheless, adding SEBS-g-MAH improved hygrothermal stability of the PLA/HNC nanocomposites.