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

• Porous polymers were successively synthesized by the Michael addition reactions of multifunctional acetoacetate and poly(ethylene glycol) diacrylate (PEGDA) compounds in mixed solvents of ethanol/dimethyl sulfoxide using a base catalyst at room temperature. • The porous polymers were formed by the connected spheres, and the monomer concentration, molecular weight of PEGDA, and structure of multifunctional acetoacetate affected size of the spheres. • The porous polymers were soft and flexible, and were no breakable by compression, absorbed various solvents. • The porous polymers, which absorbed propylene carbonate solution of a lithium salt, showed high ionic conductivity. 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.