Flexural Strength and Load–Deflection Behaviour of Hybrid Thermoset Composites of Wood and Canola Biopolymers

The study aims to incorporate cellulosic canola ( Brassica napus L.) biopolymers with wood biomass to increase flexural strength more than wood fraction alone. A facile fabrication process—at ambient temperature—is employed for ease of producing two different sets of bio-composites utilizing unsaturated polyester resin: pristine composite structures of 100% wood and hybrid composite structures of a canola-wood blend. The curing process is accompanied by methyl ethyl ketone peroxide (MEKP). Besides the lightweight feature, the hybrid composite structures exhibit maximum flexural strength up to 59.6 and 89.58 MPa at 2.5 and 5% fibre polymer fraction, outperforming the pristine wood composites (49.25 MPa). Also, the bending behaviours of the composite structures are illustrated by the load–deflection curves and the associated SEM micrographs display their fractured and debonded surface at the cross-section. The novel canola fibre benefits from its inherent hollow architecture, facilitating an excellent strength to weight ratio for the thermoset composites. Interestingly, canola displays a fibre diameter and density of 79.80 (± 41.31) μm and 1.34 (± 0.0014) g/cc, contributing effectively towards the flexure performance and high packing density. The breaking tenacity (13.31 ± 4.59 g-force/tex) and tensile strength (174.93 ± 60.29) of canola fibres are comparable to other bast fibres. The synergy among fibre diameters, density and breaking tenacity creates a good interphase to successfully transfer the external compressive load from the resin matrix to the fibres. Further, the two-parameter Weibull distribution model is applied for predicting the failure and reliability probability of composite specimens against a wide range of compressive loads. Finally, prioritized SWOT factors have been summarized associated with the prospects and key challenges of canola biopolymers—an attempt to strategize the planning and decision-making process for a potential business environment. The introduction of canola into the plastic industries would ultimately promote the application of sustainable biopolymers in diverse grounds including the interior panels for aerospace, automotive, and furniture industries. Graphic Abstract