1. pentamethyldiethylenetriamine pc-5: the star of environmentally friendly polyurethane catalyst on the stage of the chemical industry, the catalyst is like a director with outstanding skills, quietly controlling the reaction process, pushing the originally slow or even difficult chemical reaction to a climax. among these many catalysts, pentamethyl diethylenetriamine pc-5 (pentamethylenenetriamine pc-5) stands out for...