Environmental assessment of recycled mineral wool and polypropylene utilized in wood polymer composites

• Environmental impacts of replacing glass fiber with recycled mineral wool in wood polymer composites are investigated.
• Environmental viability of material re-use of polypropylene waste is studied.
• Two different end-of-life options for wood polymer composite waste are evaluated.
• Life cycle assessment methodology is used.

Environmental performance is an important promotive factor in the future use of wood polymer composites. In this study, the environmental effects of replacing virgin glass fibers with recycled mineral wool fibers, as well as replacing virgin polypropylene with recycled polypropylene are investigated. Furthermore, the environmental performance of two different end-of-life options for composite waste, incineration for energy use and landfill deposition is evaluated. The recycled mineral wool was found to have better environmental performance compared to glass fiber in every impact category assessed. The utilization of recycled polypropylene proved to be advantageous in global warming potential and abiotic depletion categories. It was found that the end-of-life management of composite waste has an important role in the environmental performance of composites. Incineration of composite waste for energy use had better performance compared to landfill deposition in all the categories assessed, except for global warming potential. It is concluded that while the environmentally optimal recycling method for polypropylene waste must be evaluated case by case, recycled mineral wool seems to provide an environmentally superior option to glass fiber in wood polymer composite applications where properties obtainable by the use of a mineral filler are required.