Facile synthesis of unsaturated polyester-based double-network gels via chemoselective cross-linking using Michael addition and subsequent UV-initiated radical polymerization

Abstract

Michael addition and UV-initiated radical polymerization of vinyl monomers were used for a one-pot synthesis of polyester-based double-network (DN) gels by chemoselective cross-linking at room temperature. Unsaturated copolyesters containing itaconate and maleate units were prepared via ternary polycondensation of maleic anhydride and itaconic anhydride with 3-methyl-1,5-pentanediol under mild conditions. The addition of a diamine to a mixture of unsaturated copolyester, methyl methacrylate (MMA), and UV-initiator in toluene at room temperature yielded the first network via chemoselective cross-linking of maleate double bonds. This network, containing MMA, was next irradiated under UV-light for 3 h to obtain a polyester/poly(MMA) DN gel with high mechanical strength and shape recovery properties. A poly(ester-co-ether)/poly(acryl amide) DN hydrogel, which swelled with 70 wt% of water after immersion in water, was also synthesized by a similar procedure.