Thermal Behaviors and Mechanical Properties of Polylactic Acid-Bagasse Composite Film

Green composites were prepared from bagasse fiber and polylactic acid (PLA) together with a single (triacetin) and the double (triacetin and glycerol) plasticizers in order to improve PLA performance at high temperature use. The presence of plasticizer improved PLA molecular mobility as observed by the reduction of glass transition, cold crystallization, and melting temperatures. The double plasticizers brought down the melting temperature as well as the decomposition temperature when compared to a single plasticizer added in the PLA/bagasse composite. The morphological study of the composites showed poor interfacial adhesion between the bagasse fiber and PLA matrix. Moreover, thermo-mechanical properties revealed the improvement of PLA performance at high temperature use by the addition of bagasse fiber and plasticizers due to cold crystallization at a high temperature which developed high storage modulus. In other words, the bagasse fiber with a single plasticizer allowed PLA to develop high strength and modulus at room temperature while the bagasse fiber with the double plasticizers improved PLA modulus at a high temperature with more ductility and competitive tensile strength at room temperature. The tensile strength of both composite films was superior in machine direction suggesting that crystallization occurred in the machine direction during blown film extrusion.