Lignocellulosic agro-residue/polylactic acid (PLA) biocomposites: Rapeseed straw as a sustainable filler

The main objective of this study is to review the applicability of rapeseed straw (RSS) as a sustainable filler material in polylactic acid (PLA)-based biocomposites. The effect of different RSS particle sizes and concentrations (0–20 wt%) on the mechanical, morphological, thermal, and water absorption properties was investigated. The composites were fabricated by melt compounding using a twin-screw extruder followed by injection molding. The mechanical properties were analyzed through tensile and flexural tests and Charpy impact tests. The morphology of the samples was investigated by scanning electron microscopy (SEM). The thermal properties and the crystallinity of the composites were determined through differential scanning calorimetry (DSC). Mechanical properties revealed an increasing stiffness of PLA as a function of RSS loading, albeit at the cost of strength. SEM images have shown a limited interfacial adhesion between PLA and the straw, which was suggested to be responsible for the decreased strength values. Based on the DSC measurements, the RSS fibers facilitated the nucleation in the composites, thereby decreasing the cold crystallization temperature of PLA. The conducted experiments demonstrated that environmentally friendly and economically attractive biocomposites can be fabricated by substituting part of the PLA with RSS as a lignocellulosic by-product.