Molar Mass Measurements of an Isocyanate Modified Polyurethane Prepolymer

Introduction

Isocyanates are both highly reactive and highly toxic low molar mass chemicals. One common technique used to take advantage of isocyanate reactivity while eliminating safety concerns is to synthesize polyurethane prepolymers for use in subsequent polymerizations. The physical properties of the resultant polymer are influenced to a large degree by the size of the polyol chains in the prepolymer. Harder polymers are formed with larger polyol chains and softer polymers are formed with smaller polyol chains.1 Here we report on the use of the EcoSEC GPC System to determine the molar mass and molar mass averages of an isocyanate modified polyurethane prepolymer (IMPP) with residual dimethyl sulfoxide (DMSO). The low dead volume of the EcoSEC GPC System combined with the use of semimicro GPC columns allowed for an efficient separation and characterization of the prepolymer sample in less than 1 hour.