Diffusivity of alkanes in polystyrene

Abstract

Gravimetry is used to study the diffusivity of a homologous series of linear alkanes (Cn, with n = 8, 10, 12, 14 and 16) in amorphous polystyrene at temperatures ranging from 45 °C to 145 °C, i.e. both below and above the polymer glass transition temperature (100 °C). All the mass uptake results obtained are well described by a simple Fickian model (for t 0.993, for all temperatures) with respect to the number of carbon atoms (n) in the alkyl chain, log(D) decreasing when n increases. For each liquid penetrant, over the temperature intervals considered, its log(D) also increases linearly (R2 > 0.996 for all the systems) with the decrease in the penetrant’s liquid viscosity.