(156d) Natural Fibers – a Novel Approach to Reinforcing Automotive Composites

As petroleum prices continue to increase, the automotive industry has ramped up efforts to reduce vehicle weight through the introduction of natural fiber reinforcement in thermoplastic and thermoset composites. In addition to their lower density, natural fibers are low cost, a renewable material and are less energy intensive to produce (grow) than glass fibers. In the current study, hemp fiber reinforced SMCs (sheet molding compounds) were prepared and compared to conventionally reinforced glass SMC for cost, density, and mechanical properties. Continuous hemp fiber (in the form of twine), non-woven hemp mats, fiberglass, and hybrids (fiberglass/continuous hemp twine mixture) were examined. Several commercial resins were screened for compatibility to the various fiber formulations and the effect of added compression during the compounding process was studied. In addition to mechanical performance, moisture uptake measurements were performed for the hemp and glass fiber reinforced materials. Selected SMC composites were evaluated against typical desired properties for automotive applications. Results show that certain formulations are currently close to target values. Next steps for additional optimization of composite formulation, fiber dispersion, fiber compatibility, and moisture resistance will be discussed.