Applications of recycled plastics and life cycle assessment

Polymers, a unique invention of last century, have influenced the everyday aspects of human life. However, its widespread usage and applications, the non-biodegradable characteristics of polymer materials, and waste mismanagement have caused permanent negative damage to the environment. Plastic debris is found everywhere – including forests, river streams, lakes, coastal lines, ocean surfaces and even the seabed. It is affecting humans and is reported as a cause of death to wildlife, birds and sea animals. When plastic waste was understood and managed well, plastic wastes could be utilised as a high value material. However, plastic waste management and recycling operations are not simple processes owing to their multitude of complexities directly or indirectly determining the environment and economic sustainability of an end-of-Life (EOL) operation. Life cycle assessment (LCA), a cradle-to-grave technique, is a holistic methodology to evaluate and assess the environmental impact of a product or a process. This research is based on conducting LCAs on various applications of recycled plastics to estimate their environmental impacts. LCA was conducted on composites containing recycled plastics to estimate environmental impacts when utilised in the construction and automotive markets in replacing virgin composites or traditional materials like wooden products. Composites based on recycled plastics were found to produce significant environmental benefits in the construction industry. Automotive applications, in a best-case scenario, were found to have an environmental profile similar to virgin material. However, combinations of construction and automotive applications are one of potential opportunities to increase the consumption rate of recycled plastics. The choice of LCIA methods was found to have a significant effect on the LCA outcome. Various contributions leading to different outcomes are evaluated and addressed.