Exploring the Coolest Path to Heat Retention

Abstract

Wetsuits have been made from polychloroprene rubber (PCR) since they were invented in 1951. PCR is produced from the intermediate chemicals butadiene (oil, PCR-B) and acetylene (limestone, PCR-A). The production process of PCR is resource and energy-intensive, and requires large chemical production facilities, which directly and indirectly emit greenhouse gas emissions and process hazardous substances. Since 2016, a natural rubber (NR) alternative, harvested from the Hevea brasilensis was introduced to the wetsuit industry, aiming to reduce the environmental impacts associated of wetsuit production. Current literature and information regarding the environmental performance of rubber alternatives lacks comprehensive quantitative analyses, complicating comparison of alternatives. Additionally, the implications of substitution PCR with NR have not been documented yet.

The goal of this research is to improve the assessment of the environmental performance of NR in comparison to PCR-A and PCR-B through a comparative cradle-to-gate LCA study, encompassing raw material extraction and rubber production. Environmental impacts are quantified using the European Union Environmental Footprint assessment method. The study seeks to inform the development of more sustainable wetsuit production and explore the environmental and industrial implications of substituting PCR with NR regarding biogenic emissions, land use, and rubber supply. The functional unit defined for this study is 1000 kilograms of rubber suitable for wetsuit production.

The research findings reveal that NR generally exhibits lower environmental impacts compared to PCR-A and PCR-B across a comprehensive range of impact categories. NR demonstrates the lowest impact in almost all categories, except for land use, where it shows a higher impact. PCR-A shows the highest environmental impacts due to significant energy and resource consumption, while PCR-B performs slightly better than PCR-A in most categories. Adjustments in gas use and biogenic emissions from agricultural practices increased the environmental impacts of NR but did not significantly alter its comparative advantage over PCR alternatives.

Substituting PCR with NR in wetsuit production suggests no significant environmental implications regarding biogenic emissions, provided the NR supply comes from FSC-certified plantations, avoiding tropical forest conversion. Converting forests would lead to considerable biogenic emissions, though still lower than those from PCR alternatives. Industrial implications regarding land use and rubber supply at scale become significant in the worst-case scenario, where the lowest yield (1,600 kg/ha/year) necessitates 54% of Thailand's domestic NR supply (2018) to meet industry demand. Conversely, with the highest yield (5,640 kg/ha/year), this requirement drops to 16% of the national supply. Globally, the lowest yield scenario requires 5% of FSC-certified plantations to meet annual demand. FSC-certified plantations have also likely increased since 2018 due to promotion efforts.

This LCA study has several limitations that need to be taken into consideration when interpreting the results. The cradle-to-gate approach excludes the use and EOL phases, this may result in some impacts being overlooked. The lack of allocation in multifunctional processes for the PCR-A system potentially lead to overestimated environmental impacts. Additionally, the exploration of possible complications related to industry wide substitution is based on limited data points. It also does not consider economic or industry dynamics, which calls for careful interpretation of the results. The study's generalized representation of NR processing may underestimate its environmental burden, especially data related to wastewater treatment.

Future research should aim to address these limitations by including the use and EOL phases, providing more detailed data on waste streams and additives in rubber production, and exploring recycling and by-product allocations to achieve a more comprehensive understanding of the environmental impacts of wetsuit production.