Strategy to control CO2 diffusion in polystyrene microcellular foaming via CO2-philic additives

•CO2-philic additives could work as CO2 concentrators in PS.•The addition of low Mn additives increases the CO2 diffusion coefficient in blends.•The CO2 desorption rate increased with the increase of the Mn of additives.•PS with PDMS (2000 g/ mol) foam presented smaller cell size and larger cell density.