Development of Starch-based Bioplastics Reinforced for Packaging Application
Biodegradable starch-based bioplastics are environmentally friendly and have attracted considerable interest to replace the conventional petroleum-based plastics. As compared to synthetic plastics, starch-based bioplastics show low mechanical and water resistance properties that hamper their applications. Therefore, the current research work focused on synthesizing starch-based bioplastics with enhanced properties by incorporating lignocellulosic fiber reinforcements with crosslinking agents. In Malaysia, the abundant natural resources such as cassava starch, oil palm empty fruit bunch (EFB) fibers, and epoxidized palm oil (EPO) derived from palm oil enable us to synthesize these bioplastics. The EFB fibers treated with 10 wt% NaOH (aq) at 180 °C demonstrated the best reinforcing effect on the physical properties of bioplastics. Low contents of the crosslinkers promoted the compatibility between fibers and starch effectively and led to a significant enhancement of tensile strength, while higher contents of crosslinkers showed a negative effect. EPO was selected as the effective modifier of the bioplastics because EPO was the most abundant commodity oil in Malaysia and the bioplastics with ESO were very brittle. However, the compatibility and reactivity between EPO and starch were low. Further, starch/TEFB-based bioplastics were modiﬁed with CA-EPO prepolymer (CEPO) using melt blending to improve the compatibility. The blending of CEPO in the composites has contributed to a higher evolution of the tensile strength than EPO. The tensile strength of the control sample increased from 3.67 to 6.90 MPa after the addition of 0.75 wt% CEPO. The water sensitivity of the composites was also moderately reduced upon the addition of both oils. This study indicated that the starch-based bioplastics with superior tensile strength and biodegradability can be used to replace part of commercial low-density polyethylene for packaging application.