Void control for polymer-matrix composites (2): Experimental evaluation of a diffusion model for the growth and collapse of gas bubbles

Abstract

Mass diffusion theory has been used to predict the rate of growth or collapse of gas bubbles in a resin precursor in order to aid the production of void-free composite materials. Simple models have been successfully compared with experimental data which show that bubble behaviour is influenced by the concentration of mobile species in the bulk resin, the concentration at the bubble/resin interface and the diffusion coefficient of these species in the resin precursor. These parameters are affected by temperature, pressure and the exposure history of the resin. Gas bubbles have been monitored and modelled for different temperatures, hydrostatic pressures and gas concentrations. The mass diffusion theory and the relationships between the processing variables and model input parameters can be used for predicting bubble behaviour during a cure schedule.