Synthesis and investigation of properties of repeatedly grafted copolymers (pemosors)

Abstract

SynopsisRepeatedly grafted copolymers (pemosors) were obtained by grafting one and the same or different vinyl monomers onto heterochain polymers in a radical reaction. As starting polymers films of polyethylene terephthalate and poly-ecaproamide were used.Styrene and methyl methacrylate were the grafted vinyl monomers. It has been shown that pemosors could be formed in yields of 500-1000~, (of the starting sample weight) by multiple grafting on vinyl polymer. Pemosors differ in appearance both from the starting polymers and the singlegraft copolymers. Investigations of pemosor samples by electron microscope showed that the morphological structure of the surface was appreciably affected, the changes being more significant with increasing content of the grafted polymer. X-Ray studies and NMR data on pemosors showed that multiple grafting of vinyl monomers does not change the crystal structure of the starting polymers, aecting only the supermolecular structure of the outer layer. Pemosors are polymers of a new type, differing in their properties from the starting polymers and the singlegraft copolymers. The grafting character and penetration depth of the grafted monomer depend on the packing compactness of the supermolecular structure of the polymeric base as well as on the chemical nature of the starting polymers and monomers. Pemosors possess considerable chemical resistance and withstand prolonged boiling in 40% alkali solution.Graft copolymers obtained by grafting various monomers on polymers activated in different ways have been described by several investigators. 1--6 Attention has been devoted chiefly to studying the process of grafting, the mechanism of the reaction, and the structure and properties of the resultant products of single-graft copolymers. Only a few records of attempts at double grafting are to be found in the literature.6-10 The possibility of multiple grafting of various monomers or of one and the same monomer has not been demonstrated until now. It might be anticipated that multiple graftings of the same or another vinyl monomer would lead to greater changes in the properties of the initial materials than single graftings and would result in polymers of a new type, with properties differing from both the initial polymers and the single-graft copolymers.This communication gives an outline of results obtained in the course of synthesizing and investigating some properties of repeatedly grafted copolymers, which are termed "pemosors."MuItiple grafting of monomers was carried out by the block method on