Atom transfer radical polymerization conditions were optimized and standardized with different initiator and catalyst systems. Acrylonitrile/n-butyl acrylate copolymers were synthesized with 2-bromopropionitrile as the initiator and CuCl/ Cu(0)/2,2 0 -bipyridine as the catalyst system. Variations of the feed composition led to copolymers with different compositions. The number-average molecular weight and the polydispersity index were determined by gel permeation chromatography. Quantitative 13 C{ 1 H} NMR was employed to determine the copolymer composition. The reactivity ratios calculated with a methodology based on the Mao-Huglin terminal model were r A ¼ 1.30 and r B ¼ 0.68 for acrylonitrile and n-butyl acrylate, respectively. The reactivity ratios determined by the modified Kelen-Tudos method were r A ¼ 1.29 6 0.01 and r B ¼ 0.67 6 0.01. 13 C{ 1 H} NMR and distortionless enhancement by polarization transfer (DEPT-45, 90, and 135) were used to distinguish methyl, methylene, methine, and quaternary carbon resonance signals. The overlapping and broad signals of the copolymers were assigned completely to various compositional and configurational sequences by the correlation of one-dimensional ( 1 H, 13 C{ 1 H}, and DEPT) and two-dimensional (heteronuclear single quantum coherence, total correlation spectroscopy, and heteronuclear multibond correlation) NMR spectral data. The complete spectral assignments of carbonyl and nitrile carbons were performed with the help of heteronuclear multibond correlation spectra. V V C 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: [2810][2811][2812][2813][2814][2815][2816][2817][2818][2819][2820][2821][2822][2823][2824][2825] 2005

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.

Copolymerization of acrylonitrile (AN) and ethyl methacrylate (EMA) using copper‐based atom transfer radical polymerization (ATRP) at ambient temperature (30 °C) using various initiators has been investigated with the aim of achieving control over molecular weight distribution. The effect of variation of concentration of the initiator, ligand, catalyst, and temperature on the molecular weight distribution and kinetics were investigated. No polymerization at ambient temperature was observed with N,N,N′,N′,N″‐pentamethyldiethylenetriamine (PMDETA) ligand. The rate of polymerization exhibited 0.86 order dependence with respect to 2‐bromopropionitrile (BPN) initiator. The first‐order kinetics was observed using BPN as initiator, while curvature in first‐order kinetic plot was obtained for ethyl 2‐bromoisobutyrate (EBiB) and methyl 2‐bromopropionate (MBP), indicating that termination was taking place. Successful polymerization was also achieved with catalyst concentrations of 25 and 10% relative to initiator without loss of control over polymerization. The optimum [bpy]0/[CuBr]0 molar ratio for the copolymerization of AN and EMA through ATRP was found to be 3/1. For three different in‐feed ratios, the variation of copolymer composition (FAN) with conversion indicated toward the synthesis of copolymers having slight changes in composition with conversion. The high chain‐end functionality of the synthesized AN‐EMA copolymers was verified by further chain extension with methyl acrylate and styrene. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1975–1984, 2006

ABSTRACT:The optimization of atom transfer radical polymerization (ATRP) conditions for the copolymerization of allyl butyl ether with acrylonitrile has been carried out with the aim of achieving control over molecular parameters. The influence of solvents, initiator concentration and in-feed molar compositions on the rate of copolymerization was also investigated. The molecular weight data as well as kinetic studies suggested conventional ATRP behavior of the copolymerization of acrylonitrile and allyl butyl ether. The variation of copolymer composition (F C ) with conversion indicated towards the synthesis of copolymers having significant changes in composition with conversion. The copolymer compositions obtained from 1 H NMR spectra were utilized to determine the reactivity ratios. With the help of DEPT (Distortionless Enhancement by Polarization Transfer) and 2D HSQC (Heteronuclear Single Quantum Coherence) NMR spectra, complete spectral assignments of 1 H and 13 C{

ABSTRACT:The copolymerization of acrylonitrile (A) and 2-methoxyethyl acrylate (M) at three different molar in-feed compositions was carried out under atom transfer radical polymerization (ATRP) conditions using 2-bromopropionitrile (BPN) as initiator and CuCl/2,2 0 -bipyridine (bpy) as catalyst system in ethylene carbonate at 60 C. Linear first order kinetics, linearly increasing molecular weight with conversion, and low polydispersities were observed for all the copolymerization. The copolymer compositions, obtained from 1 H NMR spectra, were utilized to determine the monomer reactivity ratios (r A ¼ 1:52 and r M ¼ 0:60) involved in ATRP. Two-dimensional NMR [Heteronuclear Single Quantum Correlation (HSQC) and Total Correlated Spectroscopy (TOCSY)] experiments in conjunction with onedimensional [ 1 H, 13 C{ 1 H}, and distortionless enhancement by polarization transfer (DEPT)] experiments were employed for assigning the complex and overlapping signals to various compositional and configurational sequences. The spectral assignments of carbonyl as well as nitrile carbons were done with the help of heteronuclear multiple bond correlation spectra.