In this work, styrene–methyl methacrylate copolymer particles were synthesized by suspension polymerization process with different copolymer compositions. A system was designed to measure the solubility and diffusivity of n-pentane in the synthesized copolymers. The designed system consisted of the self-sealing cell equipped to the pressure and temperature controllers. The synthesized copolymer particles were impregnated by n-pentane and their expansion were recorded visually. Furthermore, the solubility and diffusivity of n-pentane in copolymer particles were measured by the same apparatus. The effect of different foaming conditions on the solubility and diffusivity of n-pentane in the samples were examined. It was concluded that the sorption pressure and temperature have contradictory effects on the solubility and diffusivity of n-pentane in styrene–methyl methacrylate copolymers at different sorption pressures. It was concluded that with methyl methacrylate content increment in copolymer, the diffusivity and dissolved n-pentane content in copolymer were reduced.
