The Determination and Effect of Unreacted Isocyanate Groups in Rigid Urethane Foams

Abstract

A method for determination of unreacted isocyanate groups in rigid urethane foams by the infrared technique is described. The method has an average deviation of about 5% for replicates. A description of efforts directed toward adapting a chemical method for the determination of NCO in foam is given. Problems relating to water adsorbed on powdered urethane foam reacting prefer entially with the NCO groups prevented suc cessful chemical methods of measurement. In order to minimize exposure of the reactive NCO groups a procedure is described for the reproducible deposition of diisocyanate on KBr.