Foaming Power, Bubble Nature, and Sample Density Related to the Expansion Regime in Polyurethane Foams

摘要: Foamed polyurethane products were obtained from mixtures of polyolic and isocyanate compounds to which different amounts water added. The foaming process was carried out in a special homemade reactor that allows us record continuously the change volume total pressure produced by foam during its expansion period. From these measurements, associated work power derived. It is shown joined with important internal system parameters such as surface tension, viscosity, bubble mole numbers, average dimension, coalescence kinetics. closed/open nature bubbles period experimentally investigated. effect amount added on final apparent density evaluated. density, decreases increases, reaches critical value where structural collapse occurs independently temperature. A link between criticality correspondent kinetic rate suggested discussed.