Donor-Acceptor Complexes in Copolymerization. XXVIII. Role of Matrices in Polymerization of Comonomer Charge Transfer Complexes

ABSTRACT

In a proposed mechanism for the homopolymerization of comonomer charge transfer complexes to alternating

copolymers, the dimeric [D⁺⁻.. A…MX-XM…A⁻⁺..D] complexes are arranged in the form of a rigid matrix whose size is determined by the initial complex concentration. After polymerization proceeds through the matrix, uncomplexed monomers diffuse to the complexing agent affixed to the copolymer chain, new complexes are generated, and the new copolymer replicates the molecular weight of the original matrix. The addition of vanadium compound to a D-A…R_xAIX_y system converts the dimeric to monomeric complexes which form a smaller, flexible matrix and yield lower molecular weight copolymer. Nitriles which coordinate with the Al atom behave similarly to the vanadium compounds.