The radiation crosslinked films based on PLLA/PDLA stereocomplex after TAIC absorption in supercritical carbon dioxide

The absorption of triallyl isocyanurate (TAIC) to equimolar stereo blends of PLLA and PDLA (sb-PLA samples) with crosslinker (TAIC) was controlled by supercritical carbon dioxide (sc-CO2) treatment. The well-mixed sb-PLA/TAIC (sc-PLA) samples containing certain ratios of TAIC were obtained after vacuum evaporation. The sc-PLA samples were become much softer by sc-CO2 treatment. The crosslinked sc-PLA materials with different crosslinking density were prepared by irradiation treatment at different radiation doses. Gel fraction, thermal properties and mechanical properties of crosslinked samples were investigated with different sc-PLA samples irradiated at the same radiation dose of 30 kGy and sc-PLA3 irradiated at different radiation doses. The crosslinking network inhibited crystallization, and enhanced the rigidity as well as lowered brittleness of irradiated samples. Although tensile strength and Young’s modulus of sc-PLA are reduced by sc-CO2 treatment, they are much improved by radiation crosslinking at a suitable dose and the crosslinked samples become harder and tougher. The typical crosslinked obtained from sc-PLA3 irradiated at 30 kGy reveals the best thermal stability with the improved mechanical properties.