Systematic study of alcohols based co-blowing agents for polystyrene foaming in supercritical CO2: Toward the high efficiency of foaming process and foam structure optimization

Abstract A new method is presented to improve the efficiency of the supercritical CO2 foaming process and optimize the foam structure after evaluating the effect of alcohols as co-blowing agents on supercritical CO2 foaming polystyrene (PS). The simulations revealed that the solubility parameter of the blowing agents and the diffusion coefficient of CO2 for PS increased with the growth of chain length of alcohol. The addition of decanol decelerated the desorption rate of the blowing agents to maintain a higher content of blowing agents in PS, which resulted in the high cell density. Butanol improved the volume expansion ratio (VER) of the foams due to having the largest plasticization effect on PS. By combining the advantages of these two alcohols as a co-blowing agent, an optimized foam structure was obtained with smaller cell size (5.82 μm) and larger VER (5.83) than that obtained when foaming with pure CO2.