Mechanical Properties of Hemp Reinforced Poly(butylene succinate) Biocomposites

Hemp and poly(butylene succinate) (PBS) composites with 10, 15 and 20 wt% fiber loading were prepared by a film stacking compression molding method, followed by extrusion and injection molding. Inadequate wetting and heterogeneous distribution of fiber was observed in the crushed materials of 20 wt% of fiber loading. Therefore, this composite was reprocessed to investigate whether the fiber-by-matrix impregnation can be improved by repeated compression molding. Composites were prepared using untreated as well as shellac coated hemp and the resulting properties were compared. The main focus of the work is to optimize the fiber loading and to study the effectiveness of shellac, a nontoxic biomaterial as a coating agent for hemp fibers, in order to develop environment friendly low cost composite materials. From the evaluated properties, it is observed that, tensile and flexural properties increased while impact strength decreased with increase in fiber loading in comparison to PBS. Moisture absorption of fibers and the composite specimens (20 wt% fibers loading) were studied. Effect of moisture absorption on the tensile properties of the composites was evaluated. Surface modification of fiber had no significant contribution towards the mechanical behavior of the composites probably due to high processing temperature; however the fiber-matrix adhesion and resistance to moisture absorption improved to some extent. SEM analysis has corroborated the findings.