Novel Michael Addition Networks Containing Poly(propylene glycol) Telechelic Oligomers

Summary: Poly(propylene glycol) oligomers with molecular weights ranging from 1 000 to 8 000 g · mol −1 were end‐functionalized with acetoacetate groups and subsequently crosslinked using carbon‐Michael addition with PEG diacrylate. Gel fraction analysis, DMA, TGA, tensile, and swelling measurements were utilized to characterize the networks. The thermomechanical properties of the networks were analyzed with respect to the molecular weight between crosslink points ( M c ) and the critical molecular weight for entanglement ( M e ). Sampling experiments during crosslinking revealed the evolution of molecular weight with time and monomer conversion. Kinetic analyses of the Michael additions were performed using 1 H NMR spectroscopy, and the influence of basic catalyst and concentration was elucidated. Synthesis of acetoacetate networks from acetoacetate‐functionalized PPG using DBU as a basic catalyst. magnified image Synthesis of acetoacetate networks from acetoacetate‐functionalized PPG using DBU as a basic catalyst.