Improving the Compatibility and Mechanical Properties of Natural Fibers/Green Polyethylene Biocomposites Produced by Rotational Molding

In this work, sustainable rotomolded composites based on green polyethylene (Green-PE) and natural fibers (coir and agave) were studied. Fibers’ surface was treated with maleated polyethylene to improve the fiber-matrix compatibility. Samples were characterized by morphology, mechanical properties (impact, tension, and flexion) and water absorption. Results showed a more homogeneous morphology with better fiber dispersion and wetting in the treated fibers composites which lead to substantial improvements of tensile modulus from 258 MPa for the neat matrix up to 345 MPa for both, treated agave and coir composites (at 30% wt), and tensile strength from 13.7 MPa for Green-PE to 15.3 MPa for 30% treated coir composites. The positive effect of the surface treatment was also observed in flexural strength with increases up to 100% and 34% in flexural modulus. Also, impact strength was increased up to 46% and water absorption reduced up to 55% for treated fiber composites compared to untreated fiber composites. As an important observation, it was possible to obtain similar or even higher mechanical properties with the Green-PE natural fiber composites than for a petroleum-based rotomolded polyethylene, which is interesting in terms of sustainability and performances for specific applications like automotive and packaging.