Synthesis of porous PEGDMA microspheres via suspension polymerization and the effect of different porogens on the porous structure

A series of novel porous poly(ethylene glycol dimethacrylate) (PEGDMA) microspheres were prepared by utilizing different types of porogens, including toluene (TOL), cyclohexane (CYC), butyl acetate (BA) and di-n-octyl phthalate (DNOP). Their porous structure, specific surface area and particle size were systematically investigated. The SEM observation and the data derived from N 2 sorption showed that the PEGDMA microspheres using TOL or CYC as porogen had a very low BET surface area near zero. Whereas, the PEGDMA microspheres possessed obvious porous structure at both surface and inner when BA or DNOP were used as porogens. The microspheres using BA had significantly higher surface area, smaller pore diameter, narrower distribution of pore diameter, and larger particle size than the microspheres with DNOP under the same initial ratios of porogen to monomer. The mixed-porogen of BA and DNOP can also produce porous structure, but the addition of DNOP caused significantly larger pore size and lower specific surface area. The finally obtained PEGDMA microspheres using BA porogen were constructed of abundant micropores and mesopores with a high BET surface area. It is believed that the PEGDMA microspheres prepared in this work can be greatly in favor of the adsorption of metallic ions or small molecules.