Synthesis and characterization of biodegradable polyester/polyether resins via Michael-type addition

Biodegradable polyester/polyether resins were prepared by crosslinking star-shaped poly(ε-caprolactone) prepolymers bearing acrylate end groups with amino-telechelic polyethersvia Michael-type addition reaction. The influence of the chemical nature of the crosslinking agent, the molar mass of the prepolymer, and the ratio prepolymer/crosslinker were investigated with respect to the swelling behavior, thermal properties, stress–strain behavior, hydrophilicity, and water sorption of the resulting resins. Resins prepared from prepolymers and/or crosslinking agents of relatively high molar mass and/or exhibiting low degree of crosslinking are semicrystalline materials which show viscoelastic behavior, while resins exhibiting high degree of crosslinking are amorphous materials which show rubbery-elastic behavior. Crosslinking of the polyester prepolymers with PEO-based crosslinkers results in hydrophilic resins with good water sorption properties, while crosslinking with PTHF- and PPO-based crosslinkers results in hydrophobic resins, which show only low water sorption ability. Residual functional end groups in the resins, either present due to incomplete crosslinking or when using molar ratio of amine to acrylate <1 or >1 in the crosslinking step, can be used for post-processing (bio) functionalization.