Environmental impact of bioplastic blends

Abstract

Since the enormous and growing demand of plastics is a reality, the importance of the sustainability of these products is essential to the environmental conservation, from its very origin to its degradation, going through its manufacturing process. As common plastics (petro-based polymers) are made from fuel fossils, their production actively contributes to the carbon dioxide emissions, aggravating climate change. In this scenario, biobased polymers (bioplastics) seem to be eco-friendlier alternatives that will be consolidating its place in the market. In the recent years, many research and development resources have been invested in this field. But a biobased polymer is instantly better for the environment than its petroleum based alternative? How do we compare the impact of these two? The present project centers on the Life Cycle Assessment (LCA) of the production of REX-PLA (polylactide acid modified by reactive extrusion) done in a pilot plant. Furthermore, it assesses the impact and sustainability of industrial interest blends of REX-PLA with other polymers – in particular with acrylonitrile butadiene styrene (ABS) and two biobased polyamides (bio-PAs): PA 610 and PA 1010. Once described the theoretical foundations to understand the project, the methodology involves selecting and computing different sustainability and environmental impact indicators to assess the environmental effect for the transformation processes done to the different blends. Afterwards, adding up the eco-profiles (cradle-to-gate LCA) of the materials to these results, it is possible to compare the total environmental impact of the different industrial interest blends with its origin polymer (ABS, PA 610 or PA 1010) to determine if, from an environmental point of view, it is worth the production of these blends in larger scales. In the case of REX-PLA/ABS blend, transformation processes done in the pilot plant, turn into a greater impact for the environment than ABS alone, which proves that it is essential to integrate LCA practice throughout the development of environmentally friendlier products. On the contrary, both biobased polyamides blends with REX-PLA are found to be significantly ecologically-friendlier than the respective polyamides alone. In particular, a kilogram (kg) of REX-PLA/PA 610 blend requires 32.7 % less water and 24.5 % less energy to be produced than a kg of PA 610; and a kg of REX-PLA/PA 1010 blend requires 26.9 % less water and 41.4 % less energy to be produced than a kg of PA 1010