Synthesis and polymerization of simple imine monomers.

Abstract

In this research, the synthesis and polymerization of new simple imine monomers was studied. The work covered three groups of imine monomers; the azaethylenecarbonitriles, the N-methylenebenzenamines, and formaldehyde oxime and its O-alkyl derivatives. Synthesis of several azaethylenecarbonitrile monomers was attempted. Monomers with carbon aromatic substituents were found to be stable monomers, while those with carbon alkyl substituents were unstable yielding oligomeric or cyclic trimer products. Homopolymerizations by radical and anionic initiation were run on the stable imine monomers and found to produce low molecular weight polymers. Copolymerizations run on the stable monomers with radical initiation gave good results at low monomer:comonomer feed ratios but decreased as the monomer:comonomer feed ratios increased pointing to inhibition of polymerization by the imine monomers. Incorporation of the imine monomer into the copolymer increased with increasing monomer:comonomer feed ratios. The attempted synthesis of N-methylenebenzenamine and 4-methoxy-Nmethylenebenzenamine yielded the cyclic trimer form ofthe monomer. No polymerization was attempted. Formaldehyde oxime was synthesized. Because the oxime spontaneously polymerizes below 60 °C, homopolymerization with radical and cationic initiation was attempted above this temperature. However, no polymer was formed. Homopolymerization of acetaldehyde oxime was attempted with only a trace of low molecular weight oligomers formed. Copolymerization studies showed only trace amounts of the oxime incorporated into the polymer product. Synthesis of O-alkyl derivatives of formaldehyde oxime yielded two stable monomers, formaldehyde, O-benzyloxime and formaldehyde, 0-4-methoxybenzyloxime. Only the formaldehyde, O-benzyloxime monomer was used in polymerization studies. Homopolymerization and copolymerization using radical or anionic initiation yielded only a trace of product with both modes of initiation. Homopolymerization by cationic initiation gave only the cyclic trimer. Copolymerization by cationic initation gave polymers whose molecular weights and conversion decreased as the monomer:comonomer feed ratios increased. The azaethylenecarbonitrile monomers and formaldehdye, O-benzyloxime yielded both homopolymers and copolymers. In homopolymerization, yields were lower with radical initiation then with ionic initiation, although the molecular weights of the polymers formed were comparable with the two types of initiation. In copolymerizations, incorporation of imine into the polymer occurred in both radical and ionic initiation. Despite problems encountered, the future of the new field of imine polymerization remains certain.