Abstract
Nonisocyanate polyurethanes (NIPUs) show promise as more sustainable alternatives to conventional isocyanate-based polyurethanes (PUs). In this study, polyhydroxyurethane (PHU) and nonisocyanate polythiourethane (NIPTU) production and reprocessing models inform the results of a techno-economic analysis and a life cycle assessment. The profitability of selling PHU and NIPTU is rationalized by identifying significant production costs, indicating that raw materials drive the costs of PHU and NIPTU production and reprocessing. After stepping along a path of process improvements, PHU and NIPTU can achieve minimum selling prices (MSPs) of 3.15 and 4.39 USD kg(-1), respectively. Depolymerization yields need to be optimized, and polycondensation reactions need to be investigated for the reprocessing of NIPUs into secondary (2°) NIPUs. Of the NIPUs examined here, PHU has a low depolymerization yield and NIPTU has a high depolymerization yield. Fossil energy use, greenhouse gas (GHG) emissions, and water consumption are reported for the biobased production of PHU, NIPTU, 2° PHU, and 2° NIPTU and compared with baseline values for fossil-based PU production. There are options for reducing environmental impacts, which could make these pathways more sustainable. If barriers to implementation are overcome, 2° NIPUs can be manufactured at lower cost and environmental impacts than those of virgin NIPUs.