Authors
Golkaram, Milad; Mehta, Rajesh
Abstract
A major challenge in lifecycle assessment (LCA) of plastic products is allocation of the environmental burdens associated with the production of virgin plastics in the first and subsequent product lifecycles. Many end of life allocation approaches are used in plastics LCAs such as cut-off, 50:50, avoided burdens, and open loop. However, the aspect of quality in these approaches is touched without correlating it with material properties; which have a direct relationship with product functionality. For the plastics going into the recycling system, many LCA studies continue to assume full virgin material replacement, equivalent virgin material quality. Only few LCA studies use a substitution ratio or quality factor to account for reduction in material properties.[1] However, often selection of substitution ratio is dependent on expert judgement. This leads to inconsistent comparisons for the selection of substitution ratio. Further, different concepts have been introduced for the determination of circularity through use of circularity indicators and quality indicator. [2] However, these methodologies do not provide guidance on estimation of quality based on the material properties. This presentation will explain use of a quality model in LCA studies for EoL credit for plastics. The model is based on the evaluation of material quality by including 3 major factors, namely 1) material properties (mechanical, thermal, physical,…) 2) polymer-polymer contamination and 3) low molecular weight contaminations. The model generates a dimensionless parameter using a non-linear correlation as a representative for all aspects of quality using material property and purity data for the target application. Presentation will share a LCA case study demonstrating use of the quality model for allocating EoL recycling credits in a multilayer film application. 1. https://doi.org/10.1016/j.jclepro.2018.12.076 2. CIRCULARITY INDICATORS, An Approach to Measuring Circularity, Methodology.