Monomers for adhesive polymers, 4 - Synthesis and radical polymerization of hydrolytically stable crosslinking monomers

Hydrolytically stable, crosslinking bis(acrylamide)s 1a-1l or bis(methacrylamide)s 2a-2c were synthesized by reaction of acryloyl or methacryloyl chloride using primary or secondary amines. In addition, monomers 3a and 3b were obtained by amidation of 2,6-dimethylene-4-oxaheptane-1,7-dicarboxylic acid (DMOHDA) with propylamine and diethylamine, respectively. The structures of the monomers were characterized by IR, H-1, and C-13 NMR spectroscopy. All monomers containing N,N'-monosubstituted carbamide groups were solids. Those containing N,N'-disubstituted carbamide groups were water-soluble liquids. Water-soluble bis(acrylamide) 1d (N,N'-diethyl-1,3-bis-(acrylamide)propane) shows a radical polymerization reactivity in the presence of 2,2'-azobis(2-methylpropionamidine) dihydrochloride (AMPAHC) similar to that of glycerol dimethacrylate, as revealed by gelation experiments in water. 1d is hydrolytically stable in 20 wt.-% phosphoric acid and can be used to substitute dimethacrylates in self-etching dentin adhesives. Furthermore, this monomer was also suitable as a reactive diluent in composites.