Formation of macroporous styrene–divinylbenzene copolymer networks: Theory vs. experiments

Abstract

ABSTRACT:A kinetic-thermodynamic model is presented to predict the total porosities of macroporous copolymer networks formed by free-radical crosslinking copolymerization of styrene (S) and commercial divinylbenzene (DVB, a mixture of meta and para DVB isomers and ethylstyrene). The kinetic part of the model predicts, based upon the method of moments, the concentration of the reacting species, the gel, and sol properties as a function of the monomer conversion. The thermodynamic part of the model describes the phase equilibria between the gel and separated phases during the S-DVB copolymerization and predicts the volume of the separated phase, which is the pore volume of the crosslinked material, as a function of the monomer conversion. Calculation results show that the porosity of S-DVB networks increases as the polymerdiluent interaction parameter increases, or as the initial monomer concentration decreases. Porosity also increases on increasing the DVB content of the monomer mixture. Both the polymerization temperature and the initiator concentration affect significantly the kinetics of S-DVB copolymerization. However, the final porosity of S-DVB copolymers is largely insensitive to the amount of the initiator and to the polymerization temperature. All calculation results are in accord with the experimental data published previously.

Polymeric scaffolds with a double pore structure

“…Solvent evaporation or sublimation after polymerisation yields the porous polymer. The pore architecture may consist of dispersed pores in a continuous polymer matrix, interconnected pores or isolated or poorly adhered polymer spheres [16][17][18][19][20][21]13]. In the case of poly(hydroxyethyl acrylate) network polymerized in ethanol or methanol a monomer/solvent weight ratio around 50% was necessary to obtain an interconnected pore structure [20,21].…”

Semibatch operation and primary cyclization effects in homogeneous free-radical crosslinking copolymerizations

“…For the modeling of primary cyclization, two kinds of approaches can be found in the literature: cyclization is either considered to occur at a constant rate [13,[45][46][47][48] or it is treated as a bimolecular reaction (with kinetic constant usually equal to propagation) by distinguishing the local radicals from the bulk radicals [22,49].…”

Synthesis of monodisperse poly(styrene-co-divinylbenzene) microspheres with binary porous structures and application in high-performance liquid chromatography

“…Different kinds of multistage methods, such as activated swelling [10,11], seeded emulsion polymerization [12], precipitation polymerization [13], template imprinting [14,15], and membrane techniques [16,17] have been developed to prepare the monodisperse porous polystyrene particles. Preparation conditions related to the porosity formation, surface modification, structure stability, and swelling homogeneity have also been extensively investigated [18][19][20][21][22].…”