Experimental study on mass transport mechanism in poly (styrene-co-divinylbenzene) microspheres with hierarchical pore structure

Catalyst performance is highly relevant to its mass transport performance. In the present study, seven styrene-co-divinylbenzene polymer samples were synthesized by varying the amounts of crosslinker and porogen, so as to elucidate mass transport mechanism in poly (styrene-co-divinylbenzene) microspheres with hierarchical pore structure. Correspondingly, pore structure parameters of seven samples were characterized by BET and MIP. By choosing toluene as probe molecule, surface diffusion coefficient and pore diffusion coefficient of toluene inside the microspheres were measured. The experimental results indicated that both surface diffusion coefficient and pore diffusion coefficient increase with the rise of the ratio of average mesopore diameter to average macropore diameter under a certain porosity. Moreover, the rise of porosity results in greater enhancement of pore diffusion coefficient than surface diffusion coefficient. Finally, sulfonic acid groups were anchored onto polymer microspheres to investigate the relative importance of mass transport performance and catalytic performance by virtue of methyl acetate hydrolysis.