Effect of rice straw loading on morphological, thermal, gas barrier, and mechanical properties of poly(lactic acid)/poly(3-hydroxybutyrate-co-4-hydroxybutyrate) blend films

Abstract

This research focuses on enhancing the properties of polylactic acid (PLA), a biodegradable polymer known for its potential in mitigating waste accumulation issues. The inherent brittleness of PLA poses a significant challenge. To overcome this limitation, the study explores the incorporation of the biodegradable polymer poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P3HB4HB) into PLA. The PLA/P3HB4HB blend films were prepared by varying compositions from 100/0 to 60/40 wt/wt and using compression molding. The investigations indicated that the PLA/P3HB4HB 90/10 blend film exhibits superior properties, such as synergistic toughness and increased %strain. Rice straw (RS) fiber is introduced as a reinforcing fiber in the blends, expanding the study to the development of PLA/P3HB4HB/RS composite films. These composite films were created by incorporating 3, 5, and 7 phr of untreated RS fiber and compared the influences of untreated RS fiber with alkaline treated RS fiber. Consequently, the treated RS fiber demonstrates higher interfacial adhesion between RS fiber and polymer matrix, leading to improvements in mechanical and gas barrier properties. Furthermore, the treated RS fiber yields a higher %crystallinity in the composite compared to the untreated RS fiber.