Reactive processing of poly(lactic acid)/poly(ethylene octene) blend film with tailored interfacial intermolecular entanglement and toughening mechanism

摘要

In order to obtain a uniform and effectively toughened poly(lactic acid)film by blending with low content of poly(ethylene octene)(POE)with high elasticity,the tailored interfacial intermolecular interaction and entanglement between the two phases of the PLA/POE blend was innovatively constructed via the facile reactive melt blending process through the reaction of the epoxy/anhydride groups grafted on the POE chains with the end groups of PLA chains(PLA/GPOE-MPOE).It was observed that POE domains were embedded tightly in PLA matrix with a fuzzy interface and abundant interface transition area,and the impact fractured surface of the blend showed an obvious plastic deformation with less occurrence of fibrillation of PLA matrix or interfacial de-bonding.Compared with neat PLA and directly blended PLA/POE blends,the PLA/GPOE-MPOE blend exhibited much higher complex viscosity/storage modulus,much lower tanδvalues in the terminal region,and obvious strain-hardening behavior.The deviation in viscoelastic behavior of PLA/GPOE-MPOE from linear PLA indicated the enhanced molecular entanglement between the long-branched chains,resulting in an enhancement of the stretching ability during biaxial drawing of the blend.Uniform PLA/GPOE-MPOE films with draw ratio as high as 7×7 were obtained through biaxial stretching,which showed much higher tensile strength and the elongation at break than that of neat PLA and PLA/POE film.This work provides a facile method for fabricating toughening PLA films with application potentials.