Physical and mechanical properties of composites based on a linear low-density polyethylene (LLDPE) and natural fiber waste

Abstract

The influence of the content and fiber length of textile waste (cotton, flax, and hemp) on the deformation and strength properties (in tension and bending) of a linear low-density polyethylene (LLDPE) was investigated. It was found that the tensile strength increased for all composites containing hemp fibers of up to 30 wt.%. The elongation at break rapidly decreased when the filler content was raised to 10 wt.%, but thereafter changed insignificantly. The flexural strength and modulus increased considerably with filler content in the composites. On the contrary, their deformability, as expected, decreased. The influence of hemp fibers on the physicalmechanical properties of the LLDPE was somewhat more pronounced. The optimum content of fibers in the composites (30 wt.%) was significantly smaller than that usually obtained (40-50 wt.% natural fibers) for other polyolefin composites, for example, with low-density polyethylene and polypropylene matrices. The highest values of strength parameters, both in tension and bending, were reached for systems with a fiber length of up to 1 mm. The melt flow index decreased considerably with increasing fiber content in the LLDPE matrix (from 4.4 dg/min for LLDPE to 0.05-0.14 dg/min for systems containing 30 wt.% fibers). Nevertheless, processing of the composites was possible by traditional methods, for example, extrusion.