Microstructure of vinylidene chloride-ethyl acrylate copolymers by one- and two-dimensional NMR spectroscopy

Abstract

Vinylidene chloride / ethyl acrylate ( V / E ) copolymers were prepared by photopolymerization using uranyl ion as a photosensitizer at room temperature. Copolymers were characterized by chlorine estimation, gel permeation chromatography, 1 H-and 13 C-NMR, 2D heteronuclear single quantum correlation ( HSQC ) , and homonuclear 1H -2D double quantum filter correlation spectroscopy ( DQF-COSY ) . Reactivity ratios for the copolymerization of V with E were calculated using the Kelen -Tudos ( KT ) and the nonlinear error in variables ( EVM ) methods. The reactivity ratios obtained from the EVM methods are r V Å 0.80 { 0.15 and r E Å 0.87 { 0.04. The microstructure was calculated in terms of the distribution of V-and Ecentered triad sequences from 13 C { 1 H } -NMR spectra of the copolymers. 2D HSQC was used to analyze the complex 1 H-NMR spectrum and 2D COSY shows the various bond interactions, thus inferring the possible structure of the copolymers.

Methyl methacrylate/N‐(o‐/m‐/p‐chlorophenyl) itaconimide copolymers: Microstructure determination by NMR spectroscopy

“…The physical and chemical properties of polymers are influenced by their microstructure, which involves the monomer distribution in the polymer chain and the stereochemical arrangement1–3 of the various groups. Microstructural studies of copolymers are of immense help in establishing the structure–property relationship 4, 5…”

One- and two-dimensional nuclear magnetic resonance studies on the compositional sequence and the microstructure of acrylamide/acrylonitrile copolymers

“…The physical and chemical properties of polymers are influenced fundamentally by their molecular‐level microstructure which involves the character of the monomer distribution in the polymer chain and the stereochemical arrangement of various groups (tacticity) 1–3. High‐resolution nuclear magnetic resonance (NMR) spectroscopy has been particularly effective in the determination of the chain structure of polymers 4. One‐dimensional (1D) techniques were not always suitable for unequivocal signal assignments; therefore, two‐dimensional (2D) NMR, especially homonuclear (COSY, TOCSY) and heteronuclear (HETCOR) correlation spectroscopies, has been successfully applied to provide the tacticity assignments and microstructure analysis of various polymer systems 5–7…”