SYNTHESIS AND POLYMERIZATION OF IMINES AND AZADIENES - NEW POLYMERIZABLE MONOMERS

We have begun an exploratory program on the synthesis of imines and azadienes (alpha,beta-unsaturated imines) to find the best structures for monomers which will form high polymers. Imines display a very wide range of stability from existing only in the gas phase or at liquid nitrogen temperatures to complete stability depending on the substituents on the nitrogen and carbon. Among the simple imines, benzylidene cyanamide gave oligomers of DP approximately 8 with either free radical or anionic initiators. Tricyanomethanimine, C4N4, could only be obtained in solution and spontaneously homopolymerized and copolymerized with paramethoxystyrene. Among the 1-azabutadienes, 1-phenyl-1-aza-1,3-butadiene polymerized to reasonably high molecular weight polymers using anionic initiators. Cationic initiation was less successful and free radical initiators gave no polymers. Similarly, N-carboethoxy-3-methyl-1-aza-1,3-butadiene gave moderate yields of polymers with modest molecular weights. Our conclusions at this stage of our investigations are that simple imines are a quite restricted class of monomers. On the other hand, owing to ease of synthesis and ability to polymerize the 1-azadienes represent a new class of reactive monomers.