Synthesis and photopolymerization of novel N-vinyl amide monomers and synthesis and characterization of a one-component maleimide epoxy resin
In Part I, a series of novel N -vinyl amide monomers was synthesized and their photopolymerizations attempted. A series of N -alkyl or aromatic-N -vinyl formamide derivatives was synthesized. Their photopolymerization behavior was compared to that of three commercial N -vinyl amide monomers, N -vinyl formamide, N -vinylpyrrolidone, and N -vinycaprolactam. Of the synthesized derivatives, only N -benyl-N -vinyl formamide and t -butyl-α-(N -vinylformamido)methacrylate photopolymerized. The lack of polymerization in the remaining derivatives is attributed to steric hinderance due to the cis conformation of the vinyl moiety with respect to the amide bond. A crosslinker based on N -vinylpyrrolidone was also synthesized, and its photopolymerization behavior was investigated in both aqueous and bulk conditions. The kinetic behavior of this bis-N -vinylpyrrolidone crosslinker, as well as that of an analogous monofunctional N -vinylpyrrolidone monomer with a hexyl side chain was investigated. Both the crosslinker and the monomer showed substantially higher rates of polymerization than N -vinylpyrrolidone itself. This increase in rate was attributed to a decrease in termination events due to steric bulk of the monomer. In Part II, an adduct of N -(p -carboxyphenyl)maleimide and allyl glycidal ether was synthesized. The thermal curing behavior of this adduct was investigated by TGA, DTA, and DSC and compared to that of a commercial bismaleimide resin, Matrimid 5292(TM). A weight loss due to water loss upon etherification was seen by TGA, occurring at 205°C. A curing exotherm beginning at 200°C was seen by DTA and DSC. The cured polymer was dark red to brown and brittle. Initial attempts at carbon fiber composite formation were unsuccessful.