abstract: rigid polyurethane (rpu) foams are widely utilized in various industries due to their excellent thermal insulation properties, structural strength, and cost-effectiveness. traditionally, tin-based catalysts, such as stannous octoate (sn(oct)₂) and dibutyltin dilaurate (dbtdl), have been the workhorses in rpu foam production. however, increasing environmental and health concerns associated with tin catalysts have spurred the...