Micromechanics of Tensile Strength of Thermo-mechanical Pulp Reinforced Poly(lactic) Acid Biodegradable Composites

Abstract

ABSTRACT Development of materials that are biobased and environmental sound is one of the goals within the current bioeconomy. This goal comes from an increasing conscientious society that pushes manufacturers and regulators toward a sustainable development. However, to be a feasible alternative, biobased materials should also match or outperform the mechanical performance of fossil-based materials. In this study, wood pulp fiber-reinforced polylactic acid (PLA) biocomposites were prepared, tested, and compared with glass fiber reinforced polypropylene. Pre-extrusion with a kinetic mixer and subsequent injection processing ensured correct dispersion of the reinforcement. The biocomposites showed mechanical properties in line with commercial materials, comparable to composites reinforced with 20% w/w of glass fiber. Micromechanics of PLA-based biocomposites showed the existence of strong interphase between the matrix and the pulp fibers. The interfacial shear strength was around 29 MPa and with a intrinsic tensile strength of the fibers 729 MPa. These materials offer a reliable alternative to oil-based matrices reinforced with mineral fibers.