Improvement of poly(lactic acid) blown film by incorporation of natural rubber latex via dynamic vulcanization using peroxide as curing agent

Abstract

This research aims to enhance the mechanical properties of poly(lactic acid) (PLA) blown film by incorporation of natural rubber latex (NRL) and to improve the interfacial adhesion between PLA and rubber (NR) using peroxide as curing agent. Hence, the effect of the presence of NRL and dicumyl peroxide (DCP) on physical, thermal and mechanical properties as well as water and oxygen permeation of PLA blown films were studied. The thermal analysis strongly confirmed the immiscibility of PLA and NR in which Tg of PLA/NRL films did not change when NRL content increased. In order to improve the mechanical properties of PLA/NRL blown films, the interfacial adhesion between PLA and NR was improved by adding DCP as curing agent. Since PLA blended with 10 wt% natural rubber (PLA/N10) had the highest mechanical properties, PLA/N10 was selected to partially crosslink between PLA main chains and NR by using DCP. The morphological results indicated that the addition of DCP induced smaller domain sized rubber and less cavitation in films. From FTIR results, the crosslink reaction between PLA and NR was confirmed. The results showed that the mechanical properties of PLA/N10/DCP films had the highest tensile strength, Young’s modulus, elongation at break, toughness, impact strength and tear strength with an addition of DCP at 0.003 phr. Therefore, PLA/N10 blended with DCP at 0.003 phr was the optimal composition for improving the interfacial adhesion of PLA and NR.