Load-bearing structural components from natural fiber and unsaturated polyester biocomposites

Natural fiber composites, or biocomposites, have recently gained much attention due to their low cost, environmental friendliness, and their potential to compete with glass-fiber composites. However, their use for load-bearing applications has not been significantly considered due to their lower mechanical and hygrothermal properties. This paper provides an overview of a pilot project aimed at demonstrating that natural fiber composites can be used for structural applications if they are hybridized and strategically arranged in cellular topologies. Laboratory-scale cellular beams and plates were made from industrial hemp fibers, flax, and unsaturated polyester resin biocomposites, as well as hybridized material systems with woven jute, chopped glass and unidirectional carbon fibers. Material characterization studies evaluated the performance that can be obtained from different natural reinforcements while data from hybrid material systems showed that that minimal hybridization with synthetic fibers significantly improves stiffness, strength, and moisture-absorption stability. Flexural tests on the biocomposite beams and plates demonstrated adequate short-term performance and analytical evaluation of full-scale cellular biocomposite components indicates that they can efficiently compete with components made from conventional structural materials.