Bio-based composites from agricultural wastes: Polylactic acid and bamboo Guadua angustifolia

Abstract

Biopolymers as polylactic acid (PLA) have some drawbacks in processing and the final product is characterized by a high permeability to steam/gases and low thermal and mechanical resistance. The addition of reinforcement materials in the biopolymer matrix provides opportunities to minimize these disadvantages. Thus, this research focuses on the inclusion of non-wooden lignocellulosic fillers from bamboo Guadua angustifolia in a polymer matrix obtained from PLA. Three types of fillers were applied: sawdust, fiber from a Kraft process, and fiber with low lignin content. The blends of PLA reinforced with 5% organic fillers were performed on a torque rheometer at temperatures between 170 to 200℃ with the addition of glycerol as plasticizer and viscosity reducer of the system and maleic anhydride as compatibilizer. The evaluation on rheological, thermal, mechanical and morphological properties were investigated by rotational rheometry, differential scanning calorimetry (DSC), universal testing machine, wide angle X-ray diffraction (WAXD) and scanning electron microscopy (SEM). The results showed that the inclusion of the lignocellulosic material generated a positive response in obtaining polymeric biocomposite. The use of fibers subjected to a process of delignification with bleaching sequences OQPoPWa resulted in a greater influence on the mechanical strength, an adequate distribution of the fibers in the PLA matrix and the viscosity of the mixture.