Porous copolymers of trimethylolpropane triacrylate and acrylonitrile

The homopolymer of trimethylolpropane triacrylate (TMPA) was synthesized by suspension polymerization using a thermodynamically good solvent (toluene) as a porogen (vol. ratio 1:1). This polymer possesses a high specific surface area (437 m2 · g−1) and porosity (50%). It was found by sorption of benzene and cyclohexane that the majority of the pores are in the range of 1–5 nm. Sorption of phenol, a standard sorbate, from a water solution is proportional to the specific surface area of the mesopores. This sorption is higher than that of nonspecific sorbents (like styrene/divinylbenzene copolymers) and smaller than the sorption of specific ones (like acrylonitrile/divinylbenzene copolymers). Two sets of reactive copolymers were obtained. In the first set, TMPA (20–40 vol.‐%) was polymerized with acrylonitrile (AN) in the presence of a constant amount of toluene as an inert diluent (vol. ratio 1:1). In the second set of copolymers the cross‐linking degree was kept constant (30 or 40 vol.‐% of TMPA) but various solvent mixtures were used, namely: toluene/tetradecane or hexadecane, toluene/2‐ethylhexanol, cyclohexanol/tetradecane or hexadecane, cyclohexanol/2‐ethylhexanol (vol. ratio 9:1). It was found that all the copolymers are macroporous (volume of pores approx. 1,0 cm3 · g−1) but those obtained in the presence of good solvents display a higher specific surface area and hence better sorption properties towards phenol than those obtained in the presence of poor solvents. The swelling of AN/TMPA copolymers is smaller than that of the TMPA homopolymer due to the presence of additional physical crosslinks formed by the strongly polar nitrile groups.