Development of natural fiber-reinforced composite with comparable mechanical properties and reduced energy consumption and environmental impacts for replacing automotive glass-fiber sheet molding compound

To replace glass-fiber sheet molding compound (GF-SMC) using natural fiber -reinforced composites (NFRCs) in the automotive industry, this work intended to enhance mechanical properties and water resistance of NFRCs by impregnating magnesium hydroxide (MH) to kenaf fibers and fabricating composites using the vacuum bag resin transfer molding (VBRTM) technology. The modulus of rupture and tensile strength of modified composites were significantly increased by 73.9% and 54.6% compared with that of the regular NFRCs, respectively. Based on the scanning electron microscope observation, it was found that the MH impregnation significantly enhanced the compatibility of kenaf fibers and polymer matrix, benefiting to the mechanical-property improvements of the composites. Compared to the regular NFRC, the 24-h water absorption and thickness swelling of MH impregnated NFRC (MH-NFRC) were significantly reduced by 83.9% and 84.2%, respectively. When the composite density was factored in the comparison of MH-NFRC and GF-SMC, the specific modulus of rupture and tensile strength of MH-NFRC were 116.4% and 109.0% of the GF-SMC, respectively. Apart from the mechanical properties, the advantages of replacing GF-SMC by MH-NFRC were reflected in the reductions of energy consumption and environmental impacts. It was calculated that the energy consumption of fabricating MH-NFRC was decreased by 33.1% compared with GF-SMC. The comparisons of environmental impacts of MH-NFRC and GF-SMC were performed by life-cycle assessment (LCA) using the SimaPro software. The results demonstrated that the environmental burdens of the composites were reduced by 22.8%, when kenaf fibers were used. All major indices of environmental impacts of MH-NFRC, including the total Global warming, Acidification, Human Health (HH) cancer, HH noncancer, HH criteria air pollutants, Eutrophication, Ecotoxicity, Smog, Natural resource depletion, Habitat alteration, Water intake and Ozone depletion, were reduced by 13.66-51.91%, respectively. It was concluded that the newly developed NFRC had great potential for replacing the GF-SMC in automobile applications, with reduced energy consumption and environmental impacts. (C) 2018 Elsevier Ltd. All rights reserved.