Investigation of microstructure of the acrylonitrile-styrene-glycidyl methacrylate terpolymers by 1D and 2D NMR spectroscopy

Abstract

Acrylonitrile-styrene-glycidyl methacrylate (N/S/G) terpolymers were prepared by bulk polymerization by using benzoyl peroxide as initiator and analyzed by NMR spectroscopy. The compositions of terpolymers were determined by quantitative 13C{1H}-NMR spectra and compared with those calculated by Goldfinger's equation by using comonomer reactivity ratios: rNS = 0.04, rSN = 0.40; rNG = 0.22, rGN = 1.37; rSG = 0.44, rGS = 0.53. The 13C{1H}- and 1H-NMR spectra were overlapping and complex. The spectral assignments were done with the help of distortionless enhancement by polarization transfer and two-dimensional 13C-1H heteronuclear single quantum correlation experiments. 2D total correlated spectroscopy was used to ascertain the various coupling between the protons. The methyl, methine, methylene, and oxymethylene carbon resonances showed compositional sensitivity. 2D nuclear Overhauser enhancement spectroscopy (NOESY) experiment was used to ascertain the spatial proton-proton couplings.