Binary-additives Toughened Biopolymer for Packaging Application

The toughening of poly(lactic acid) or PLA with Monmorillonite clay (MMT), polyamide-block-ether (PEBAX) and hyperbranched polymer (Boltorn®) was investigated. PLA was first blended with 1, 2, 2.5, 3 and 4%wt of MMT, 5-20%wt of PEBAX and Boltorn® for a single additive system. For the binary additive system, PEBAX and Boltorn® 5-20%wt were pre-mixed with 2.5%wt of MMT, and then they were added to PLA. PLA blendes were prepared by an internal mixer. Tensile properties, impact properties and morphology of PLA blends were investigated. For single additive with PLA, adding MMT showed the increasing of toughness of PLA. PLA/PEBAX blends were shown the increasing of elongation and impact strength with containing PEBAX content, but modulus and tensile strength decreased. The results of PLA/Boltorn® blends were similar with PLA/PEBAX blends. Furthermore, elongation and impact strength of PLA blends can be improved by adding PEBAX binary additive, modulus and tensile strength decreased but not as severe as single additive. Adding Boltorn® as in a binary additive led to the brittleness and less elongation of blends when compared to adding a single additive and neat PLA.