Life cycle assessment of kenaf fiber reinforced biocomposite

This study investigates the environmental performance of kenaf fiber reinforced biocomposite (polyhydroxybutyrate/kenaf fiber) via life cycle assessment and compares its environmental performance to that of glass fiber reinforced composite (polypropylene/glass fiber). The system boundary in the analysis covers the entire life cycle of kenaf fiber reinforced biocomposite from cradle to grave. Two waste management scenarios are included in the analysis to determine the environmental effects due to waste management scenarios: landfill and composting. Using kenaf fiber reinforced biocomposite as a raw material for automobile parts instead of glass fiber reinforced composite can reduce nonrenewable energy consumption by 23-24% and greenhouse gas emissions by 6-16%. However, the kenaf fiber reinforced biocomposite product system produces more local environmental impacts such as photochemical smog formation, acidification and eutrophication than the glass fiber reinforced composite product system because of nutrient losses to the environment during biomass production. Among the environmental impacts considered in this study, only greenhouse gas emissions associated with the kenaf fiber reinforced biocomposite product system are significantly affected by the waste management scenarios. The composting scenario produces less greenhouse gas emissions than the landfill scenario because some of the carbon in kenaf fiber reinforced biocomposite is sequestered in soil as soil organic carbon when compost made from kenaf fiber reinforced biocomposite is applied to the land. The environmentally sensitive sub-processes for nonrenewable energy consumption and greenhouse gas emissions are polyhydroxybutyrate manufacturing, injection molding and kenaf fiber production processes. Polyhydroxybutyrate manufacturing and injection molding are energy intensive processes. The sodium hydroxide solution used in the fiber surface treatment is the primary environmentally sensitive parameter in kenaf fiber production process in terms of nonrenewable energy consumption and greenhouse gas emissions.