SYNTHESIS OF HIGHLY POROUS STYRENE-DIVINYLBENZENE COPOLYMERS PREPARED IN THE PRESENCE OF 2,2,4-TRIMETHYLPENTANE

A large number of styrene-divinylbenzene copolymers (St-DVB) were synthesized using 2,2,4-trimethylpentane as pore-forming agent. Diluent and crosslinking agent (DVB) contents were varied in the ranges 20 - 60 vol.-% and 2 - 40 vol.-%, respectively, to generate various St-DVB networks. Network features as apparent and skeletal densities, pore volume, mean pore diameter, specific surface area and pore size distributions were measured by mercury porosimetry. A compressing process occurring at the beginning of each measurement has been revealed and measured. Depending on the two synthesis parameters, the changes in pore diameter distributions are discussed. Those results, combined with the calculated average pore diameter and microscopy observations, allow to conclude that the synthesized matrices have a microsphere-bed structure with a network-overlapping process occurring over 50 vol-% of dilution. A macroporosity domain has been defined for networks having specific surface areas greater than 130 m(2)/g.