Cure Terms Glossary

Prepolymer


A prepolymer is created when a cure is held at an intermediate stage by attention to the reaction stoichiometry. An excess of one or other reagent is used to limit the extent of cure. When an excess of isocyanate is used in a polyurethane formulation the intermediate product is called an isocyanate prepolymer. When an excess of phenol is used in a phenol-formaldehyde resin formulation, the intermediate product is called a novolak.