Synthesis of porous polymers by means of Michael addition reaction of multifunctional acetoacetate and poly(ethylene glycol) diacrylate

Michael-addition reaction between multifunctional-acetoacetate, meso-erythritol tetra-acetoacetate (ETAA) or d-sorbitol hexa-acetoacetate (SHAA), and poly(ethylene glycol) diacrylate (PEGDA) has been investigated to obtain the corresponding network polymer. The reactions in mixtures of ethanol (EtOH) and dimethyl sulfoxide (DMSO) using 1,8-diazabicyclo[5.4.0]undecane-7-ene (DBU) as a catalyst successfully yielded porous polymers. Polymerization conditions, such as EtOH/DMSO volume ratio, DBU/PEGDA feed ratio, and monomer concentration, strongly affected the morphology of the network polymer products, i.e., gel, porous polymer, or precipitate. The surface morphology of the porous polymers showed connected spheres with diameters ranged from 2 μm to 50 μm. The monomer concentration and molar mass of PEGDA affected the diameter of the spheres in the porous polymers. All the porous polymers were soft and flexible, and were not breakable by compression. Various solvents were absorbed into the porous polymer due to their high affinity with polyethylene glycol units in the network structure.