A model to predict the cell density and cell size distribution in nano-cellular foams

摘要: Abstract A numerical model is developed to simulate the simultaneous bubble nucleation and growth during depressurization of thermoplastic polymers saturated with supercritical blowing agents. Of particular importance ability predict formation nano-cellular foams, including cell size distribution within foam, based on specific process conditions polymer properties. Additionally differentiates between “Free” “Limited” expansion phases in a single bubble. Classical theory used rate popular “Influence Volume Approach” determine end phase. By solving mass, momentum species conservation equations for each bubble, capable predicting bulk porosity. It found that by accurately capturing concentration gradient agent boundary layer surrounding applying appropriate at different stages growth, able making foams. Unlike micro-cellular foams diffusion controlled period short viscosity-controlled crucial generating maximum nuclei density. Experimental data obtained foaming acrylate copolymers CO2 as compare well predictions average porosity distribution. Furthermore, effect curve are delineated.