Reaction injection molding of polyureas. II: Rheo‐kinetic changes and model simulation

An experimental and theoretical study of reaction injection molding (RIM) of polyurea was conducted in this work. A lab‐scale RIM machine was used to carry out the polyurea bulk polymerizations. A “free‐table” viscometer was designed to measure the fast rheological changes and liquid‐solid transition. A mathematical model was proposed to simulate the fast reaction and rheological changes in the polyurea RIM process. The parameters of this model were determined based on the solution polymerization data from FTIR and Haake rheometer measurements. Combined with an appropriate heat transfer equation, this model predicts fairly well the adiabatic temperature and viscosity rises of bulk polyurea reactions in RIM.