Design of polymeric microparticles with improved structural properties: Influence of ethylstyrene monomer and of high proportions of crosslinker

Macroreticular poly(styrene-co-divinylbenzene) microparticles with high proportions of divinylbenzene have been synthesized and the effects of the operating conditions and of the proportion of ethylstyrene, which is the monomer accompanying divinylbenzene in commercial divinylbenzene, on the structural characteristics of the microparticles have been investigated. The use of commercial divinylbenzene with a purity of 80% enabled the synthesis of microparticles with a high grade of crosslinking, which showed enhanced structural properties, such as BET specific surface areas (some types of particles reached more than 500 m2 g−1) or pore volumes (mesopore volumes higher than 0.7 cm3 g−1, and macropore volumes higher than 0.5 cm3 g−1). At the same time, microparticles with the same percentage of divinylbenzene but a different percentage of ethylstyrene were synthesized by using, as raw material, two types of commercial divinylbenzene with purities of 80% and 55%, respectively. Comparison of the properties of both these types of particle indicated that ethylstyrene has a significant effect on macropore volume in the case of the lowest proportion of porogen in the synthesis mixture, within the range of values investigated.