Application of cluster analysis and optimization to determine the synthesis conditions of macroreticular poly(styrene-co-divinylbenzene) microparticles with enhanced structural and adsorption properties

A suitable porous structure and high mechanical strength are extremely valuable properties in adsorbent polymeric microparticles. To achieve this objective, macroreticular poly(styrene-co-divinylbenzene) microparticles with high amounts of cross-linker and diverse proportions of porogen agent were synthesized according to the methodology of the factorial design of experiments. The structural characteristics of the microparticles and their adsorption properties of a model macromolecule (bovine serum albumin (BSA)) were studied. From the results obtained, as well as those observed in previous works [C. Garcia-Diego, J. Cuellar, Synthesis of macroporous poly(styrene-co-divinylbenzene) microparticles using n-heptane as the porogen: quantitative effects of the DVB concentration and the monomeric fraction on their structural characteristics, Ind. Eng. Chem. Res. 44 (22) (2005) 8237–8247; C. Garcia-Diego, J. Cuellar, Determination of the quantitative relationships between the synthesis conditions of macroporous poly(styrene-co-divinylbenzene) microparticles and the characteristics of their behaviour as adsorbents using bovine serum albumin as a model macromolecule, Ind. Eng. Chem. Res. 45 (10) (2006) 3624–3632], it was decided to apply a cluster analysis to all the adsorbents with a view to determining the range of synthesis conditions that would allow the synthesis of microparticles with high mechanical strength and a porous structure appropriate for absorbing the BSA macromolecule. This range was found to be 0.50–0.60 for the monomeric fraction and 25.0–55.0% for the divinylbenzene concentration in the monomeric mixture. Additionally, through use of the desirability function, the results revealed that the adsorbent with the optimum adsorption characteristics, as regards both adsorption equilibrium and adsorption kinetics, should be synthesized with a DVB concentration of 42.5% and a monomeric fraction of 0.50.