Chapter 7. Life Cycle Assessment of Sustainable Polymer Packaging

Abstract

With the increasing global demand for plastic, research efforts have been focused on renewable alternatives to fossil-derived plastics and sustainable end-of-life options. Biomass from terrestrial or aquatic plants is used as the renewable raw material for polymers production, which are often referred to as ‘bio-based’. Bio-based plastic life cycles largely consist of four phases: terrestrial or aquatic plant cultivation; polymer (e.g. polysaccharides) extraction; bio-based plastic production; and end-of-life. As a systematic and rigorous evaluation framework, Life cycle sustainability assessment (LCSA) provides an integrative and holistic perspective for multi-criteria decisions on a given product or system. LCSA consists of three pillars, environmental life cycle assessment (LCA), life cycle costing and social-LCA. This chapter focuses on the environmental aspects and presents two LCA case studies to discuss different types of biodegradable biopolymers, including starch-based bio-composite and biosynthesized polymer. The focus of LCA case studies is to highlight environmentally damaging steps and compare the bioplastic with petrochemical counterparts. Regardless of processing technologies, both starch-based bioplastic case studies suggest environmentally damaging steps focusing on feedstock resources, applications and end-of-life. Despite the environmental advantages of bioplastic at the refinery gate, starch-based bio-packaging in general cannot compete with petrochemicals with closed-loop recycling at end-of-life. This chapter also provides an overview of sustainable polymers sourced from renewable resources and discusses a range of carbon sinks and emitters, energy sinks and sources emerging from bioplastic life cycles. Our research highlights the life cycle insights derived LCA and systems engineering approach. By process integration and optimization in particular by minimizing energy sinks and carbon emitters, sustainable polymers produced from renewable resources have great potentials to contribute to a sustainable circular economy (CE).