Foaming Kinetics of Closed Cell Rigid Polyurethane Foam

Abstract

Rigid polyurethane foams have shown promise in several applications as a means to reduce weight without compromising structural properties. Information about the chemical formula of the liquid components, the reaction to produce foaming, and the curing kinetics of rigid polyurethane foam are discussed. The chemical formulas of the liquid components are described, and the reaction required to produce foaming and cure of the polyurethane is stated. The foaming kinetics of the polyurethane were determined based on experimental work as well as theoretical modeling. It was determined that there was a relationship between the initial load the frame was placed under and the amount of pressure measured during the foaming process. The theoretical modeling was conducted for an equilibrium scheme as well as viscosity and diffusion controlled stages. Each of the models predicted the bubble growth to be much quicker than was seen in experimental work, but captured dimensional properties in the foam. The curing kinetics of the liquids and thermal profile of the foaming reaction were measured and a plan for incorporation into future modeling is discussed.