Unconventional microstructure of maleic anhydride copolymers in condensed and dissolved states

Abstract

AbstractA novel type of protopropic tautomerism proceeds in macromolecules of binary copolymers of maleic anhydride (MA) with vinyl acetate (VA) and vinyl chloride (VC) giving rise to spontaneous formation of dynamic micro structural heterogeneity which consists of several tautomeric forms: succinic anhydride rings, VC and VA units along with unforeseen enol (en) and dienol (den) furan derivatives (33 mol%). The arising hydrogen bonds close the ring generating quasi-aromatic structures simultaneously. The en and den tautomers form charge-transfer complexes with O- and N- nucleophiles. Mechanism of MA radical copolymerization with VC including polyaddition of molecular monomer complexes both in the ground state and in their biradical resonance structures has been proposed. The investigations were carried out using infrared spectroscopy (IR-), electron, nuclear magnetic resonance spectroscopy (1Н and 13С NMR), differential thermo analysis, mathematical microstructure modelling etc.