Comprehensive 2D NMR analysis: Acrylonitrile/ethyl methacrylate copolymers synthesized by ATRP at ambient temperature

Abstract

Copolymerization of acrylonitrile and ethyl methacrylate using atom transfer radical polymerization (ATRP) at ambient temperature was carried out under optimized reaction conditions using 2-bromopropionitrile as initiator and CuBr/2,2 0bipyridine as the catalyst system. The copolymer composition, obtained from 1 H NMR spectra, were used to determine the monomer reactivity ratios (r A ¼ 0.68 and r E ¼ 1.75) involved in ATRP. Two-dimensional NMR (heteronuclear single quantum correlation and total correlated spectroscopy) experiments were employed to resolve the highly overlapping and complex 1 H and 13 C{ 1 H} NMR spectra of copolymers. The complete spectral assignments of the quaternary carbons viz. carbonyl and nitrile carbons were done with the help of heteronuclear multiple bond correlation spectra.

2D NMR Analysis of Acrylonitrile/2-Methoxyethyl Acrylate Copolymers Synthesized by Atom Transfer Radical Polymerization

“…62 The theoretical outfeeds at high conversions were calculated by following the model proposed by Heatley et al 63 and Mao and Huglin 64 and optimization was done as described earlier. 28,37,52 The optimized reactivity ratio values were found to be r A ¼ 1:52 and r M ¼ 0:60, which were in good agreement with those reported earlier. 28 Any variation in the relative concentration of monomer may incorporate gradiency in the copolymer chains due to different monomer reactivity ratios.…”

Two-dimensional NMR studies of acrylate copolymers

“…The microstructure of a large number of copolymers such as methyl methacrylate/methyl acrylate (A/B) [61,62], 2-hydroxy ethyl methacrylate/2-vinyl pyridine [63], acrylonitrile/methyl methacrylate [59], and ethyl methacrylate/acrylonitrile [64] have been investigated by Brar et al Recently, they have assigned the complex carbon and proton NMR spectra of glycidyl methacrylate/vinyl acetate, methacrylonitrile/methyl methacrylate [65], N-vinyl-2-pyrrolidone/acrylonitrile, N-vinyl-2-pyrrolidone/methyl acrylate, glycidyl methacrylate/methyl styrene [66], and glycidyl methacrylate/butyl acrylate [67] in terms of compositional and configurational sequences with the help of DEPT, HSQC, TOCSY, and NOESY NMR experiments. They have also assigned the complex 1 H, 13 C{ 1 H} NMR spectra of a large number of copolymers such as styrene/n-butyl acrylate [68], styrene/methyl methacrylate [69], N-acryloylcarbazole/methyl methacrylate [70], N-acryloyl carbazole/methacrylonitrile [71], and acrylonitrile/methyl acrylate [72] with the help of DEPT, HSQC, TOCSY, and HMBC experiments.…”

Optimization of Atom Transfer Radical Copolymerization of Allyl Butyl Ether with Acrylonitrile

“…38 The theoretical outfeeds at high conversions were calculated by following the model proposed by Heatley et al 39 and Mao and Huglin 40 and optimization was done as described earlier. 41 The optimized reactivity ratios were found to be r A ¼ 6:01 and r C ¼ 0:10, revealing the lower reactivity of allyl butyl ether for the copolymerization.…”