Sequencing of N‐vinyl‐2‐pyrrolidone/glycidyl methacrylate copolymers by one‐dimensional and two‐dimensional nuclear magnetic resonance spectroscopy

Copolymers of N‐vinyl‐2‐pyrrolidone (V) and glycidyl methacrylate (G) monomers of different compositions were prepared by free‐radical solution polymerization. The copolymer composition of these copolymers was determined with ¹H‐NMR spectra. The reactivity ratios calculated from the Kelen–Tudos and nonlinear least‐square error‐in‐variable methods were r_V = 0.03 ± 0.01 and r_G = 5.05 ± 0.84 and r_V = 0.02 and r_G = 4.72, respectively. The triad sequence distribution in terms of V and G centered triads was determined from ¹³C{¹H}‐NMR spectroscopy. The complete spectral assignment of ¹³C{¹H}‐ and ¹H‐NMR spectra was performed with the help of distortionless enhancement by polarization transfer and two‐dimensional ¹³C–¹H heteronuclear single quantum coherence. The ¹H–¹H couplings were explained with total correlation spectroscopy and nuclear Overhauser enhancement spectroscopy spectra. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 50–60, 2002; DOI 10.1002/app.10186     

Investigation of microstructure of the N‐vinyl‐2‐pyrrolidone/methyl methacrylate copolymers by NMR spectroscopy

The copolymers containing N‐vinyl‐2‐pyrrolidone (V) and methyl methacrylate (M) units of different compositions were synthesized by free radical bulk polymerization. The copolymer composition of these copolymers was determined by CHN analysis. The distortionless enhancement by polarization transfer (DEPT) technique was used to resolve the methine, methylene, and methyl resonance signals in the V/M copolymer. Comonomer reactivity ratios were determined by the Kelen–Tudos (KT) and nonlinear least‐square error‐in‐variable (EVM) methods. ¹H–¹³C Heteronuclear shift quantum correlation spectroscopy (HSQC) and ¹H–¹H homonuclear total correlation spectroscopy (TOCSY) spectra were used for the resolution of the proton nuclear magnetic resonance (¹H NMR) spectrum of the V/M copolymers. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1328–1336, 2002     

Structural investigations of (9‐ethyl‐carbazol‐6‐yl) methyl methacrylate/methyl acrylate copolymers using two‐dimensional NMR spectroscopy

(9‐Ethyl‐carbazol‐6‐yl) methyl methacrylate/methyl acrylate (E/A) copolymers of different compositions were prepared by solution polymerization by varying the molar infeed ratio, using AIBN as initiator at 60°C. The reactivity ratios calculated by Kelen–Tudos (KT) method were found to be r_E = 1.16 ± 0.02 and r_A = 0.69 ± 0.01 whereas those calculated from RREVM method were found to be r_E = 1.18 and r_A = 0.68. The molecular weights (M_w) and polydispersity index (PDI, M_w/M_n) were determined using gel permeation chromatography (GPC). Glass transition temperatures (T_g) for different compositions of E/A copolymers were determined using differential scanning calorimetry (DSC). Copolymer molar outfeed ratio (F_E) was calculated from ¹H NMR spectra. The α‐methyl, methine, backbone methylene, and quaternary carbon resonance signals of the copolymers were distinguished using ¹³C{¹H}, DEPT‐45, ‐90, and ‐135 NMR techniques. The α‐methyl and β‐methylene showed compositional and configurational sensitivity up to pentad and tetrad level, respectively, whereas methine showed only compositional sensitivity up to pentad level. Unambiguous assignments for ¹H and ¹³C{¹H} NMR spectra were done by correlating 1D (¹H, ¹³C{¹H}, DEPT) and 2D (HSQC, TOCSY) NMR data. The spectral assignments for carbonyl region were done by studying higher bond order couplings by heteronuclear multibond correlation (HMBC) spectra. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5595–5606, 2006     

Sequencing of methyl methacrylate/vinylidene chloride copolymers by NMR spectroscopy

Methyl methacrylate/vinylidene chloride (M/V) copolymers of different monomer concentrations were prepared by photopolymerization using the uranyl ion as photosensitizer. The copolymer composition was determined by chlorine estimation of the copolymers. The complete assignment of the ¹³C{¹H} NMR spectra of these copolymers is made by comparison with the spectra of poly(methyl methacrylate) and observing the changes in the intensities of the resonances with copolymer composition. The quaternary carbon of V- and M- center resonances were used for determining the sequence in terms of the distribution of V- and M- centered triads. The triad fractions thus obtained were compared with theoretically determined triad concentrations. The Monte Carlo simulation method was also used for estimating the copolymerization behavior. The variation of V- and M- centered triad concentrations was reported as a function of fractional conversions. The comonomer reactivity ratios, determined by both Kelen Tudos and nonlinear error in variables methods are r_V = 0.26 ± 0.04 and r_M = 2.88 ± 0.23. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 70: 373–381, 1998     

Microstructure analysis of methyl acrylate/methyl methacrylate copolymers by two‐dimensional NMR spectroscopy

Methyl acrylate (A)/methyl methacrylate (B) copolymers of different compositions were synthesized in bulk at 50°C and the compositions were determined from ¹H NMR spectra. Reactivity ratios were optimized using the least square methodology. Compositional and configurational assignments were done using two‐dimensional (2D) Heteronuclear Single Quantum Correlation (HSQC) and Total Correlation Spectroscopy (TOCSY) experiments. Methylene proton and carbon resonances were assigned for compositional and configurational sensitivity at tetrad level. Carbon resonances of methine group of methyl acrylate were assigned for compositional sensitivity up to triad level with the help of 2D HSQC spectra. α‐Methyl group of methyl methacrylate was assigned up to triad level of compositional and configurational placements for carbon and proton resonances by 2D HSQC spectroscopy. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1437–1445, 2006     

Microstructure analysis of N‐vinyl‐2‐pyrrolidone/vinyl acetate copolymers by NMR spectroscopy

N‐Vinyl‐2‐pyrrolidone (V) and vinyl acetate (A) copolymers of different compositions were synthesized by free radical bulk polymerization. The copolymer composition of these copolymers was determined using quantitative ¹³C{¹H} NMR spectra. The reactivity ratios for these comonomers were determined using the Kelen–Tudos (KT) and non‐linear least‐square error‐in‐variable (EVM) methods. The reactivity ratios calculated from the KT and EVM methods are r_V = 2.86 ± 0.16, r_A = 0.36 ± 0.09 and r_V = 2.56, r_A = 0.33, respectively. ¹H, ¹³C{¹H} and ¹H–¹³C heteronuclear shift correlation spectroscopy (HSQC) and ¹H–¹H homonuclear total correlation spectroscopy (TOCSY) were used for the compositional and configurational assignments of V/A copolymers. The ¹³C distortionless enhancement by polarization transfer (DEPT) technique was used to resolve the methine, methylene and methyl resonance signals in the V/A copolymers. © 2002 Society of Chemical Industry     

Microstructure analysis of methyl acrylate/methyl methacrylate copolymers by two‐dimensional NMR spectroscopy. II

In the present article, a comprehensive two‐dimensional heteronuclear multi bond correlation (HMBC) spectral analysis of methyl acrylate (A)/methyl methacrylate (B) copolymers is reported. The methylene carbon and methine carbon resonances assigned from the 2D HSQC spectroscopy were established by analyzing the two and three bond order couplings with α‐methyl protons, methylene protons, and methine protons. Quaternary carbon resonances of the B unit were assigned by investigating the two bond order couplings with α‐methyl protons and methylene protons. Assignments of carbonyl carbon resonances based on the analysis of three bond couplings with α‐methyl protons and methylene protons are reported. The analyses present comprehensive assignments of the carbonyl carbon resonances showing the critical contribution of 2D HMBC spectroscopy in the indirect analysis of carbon resonances. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

Investigation of microstructure of 4‐vinyl pyridine–methacylonitrile copolymers by NMR spectroscopy

4‐Vinyl pyridine–methacrylonitrile (V/M) copolymers of different composition were prepared by bulk polymerization using benzoyl peroxide as an initiator. The copolymer composition was determined from quantitative ¹³C{¹H}‐NMR spectra. The reactivity ratios for V/M copolymer obtained from a linear Kelen‐Tudos method (KT) and nonlinear error‐in‐variables method (EVM) are r_V = 0.79 ± 0.12, r_M = 0.38 ± 0.09 and r_V = 0.79 ± 0.13, r_M = 0.38 ± 0.07, respectively. The complete spectral assignment in term of compositional and configurational sequences of these copolymers were done with the help of distortionless enhancement by polarization transfer (DEPT), two‐dimensional heteronuclear single quantum coherence spectroscopy (HSQC). Total correlated spectroscopy (TOCSY) experiment was used to assign the various three‐bond ¹H‐¹H couplings in the V/M copolymer. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 3232–3238, 2003     

New self‐crosslinkable copolymers based on N‐methyl‐N‐vinylbenzylpyrrolidinium halide and methyl methacrylate

Thermally‐induced self‐crosslinking behaviour has been found in copolymers containing N‐methyl‐N‐vinylbenzylpyrrolidinium chloride (MVBPC) and methyl methacrylate (MMA). NMR, IR and low molecular weight model reactions demonstrate that this crosslinking reaction occurs between the methyl ester groups of the MMA units and the quaternary ammonium salts, with the resulting benzyl esters forming chemical links between the MVBPC and MMA units with the formation of N,N‐dimethylpyrrolidinium chloride. Similar crosslinking behaviour has also been found when the Cl⁻ anion is replaced by Br⁻ and I⁻, but not in the case of BF as counter anion. © 2000 Society of Chemical Industry     

Microstructure determination of the acrylonitrile–styrene–methyl methacrylate terpolymers by NMR spectroscopy

Acrylonitrile–styrene–methyl methacrylate (A–S–M) terpolymers were prepared by photopolymerization using uranyl nitrate ions as photo initiators, which were analyzed by NMR spectroscopy. The terpolymer compositions were determined by Goldfinger's equation using comonomer reactivity ratios: r_as = 0.04; r_sa = 0.31; r_am = 0.17, r_ma = 1.45; r_sm = 0.52; r_ms = 0.47. The terpolymer compositions were also determined from the quantitative ¹³C(¹H)‐NMR spectroscopy. The sequence distribution of the acrylonitrile‐, styrene‐, and methyl methacrylate–centered triads were determined from the ¹³C(¹H)‐NMR spectra of the terpolymers and are in good agreement with triad concentrations calculated from the statistical model. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 3026–3032, 1999     

Synthesis and characterization of poly[4‐(2‐thiazolylazo)phenyl methacrylate]‐co‐poly(methyl methacrylate)

A new methacrylic monomer, 4‐(2‐thiazolylazo)phenylmethacrylate (TPMA) was synthesized. Copolymerization of the monomer with methyl methacrylate (MMA) was carried out by free radical polymerization in THF solution at 70 ± 0.5°C, using azobisisobutyronitrile (AIBN) as an initiator. The monomer TPMA and the copolymer poly(TPMA‐co‐MMA) were characterized by Fourier transform infrared (FTIR), ¹H nuclear magnetic resonance (NMR), and elemental analysis methods. The polydispersity index of the copolymer was determined using gel permeation chromatography (GPC). Thermogravimetric analysis (TGA) of the copolymer performed in nitrogen revealed that the copolymer was stable to 270°C. The glass transition temperature (T_g) of the copolymer was higher than that of PMMA. The copolymer with a pendent aromatic heterocyclic group can be dissolved in common organic solvents and shows a good film‐forming ability. Both the monomer TPMA and the copolymer poly (TPMA‐co‐MMA) have bright colors: orange and yellow, respectively. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2152–2157, 2007     

Synthesis and characterization of N‐acryloylcarbazole/methyl methacrylate copolymers

Copolymers of N‐acryloylcarbazole (A) and methyl methacrylate (M) were synthesized in different in‐feed ratios. The composition of the copolymer was determined by the help of ¹H NMR spectrum. The comonomer reactivity ratios determined by Kelen‐Tudos (KT) and nonlinear error‐in‐variables methods were r_A = 1.12 ± 0.16, r_M = 0.94 ± 0.14, and r_A = 1.05, r_M = 0.90, respectively. Complete spectral assignments of the ¹H and ¹³C ¹H NMR spectra of the copolymers were done by the help of distortionless enhancement by polarization transfer (DEPT) and two‐dimensional NMR techniques, such as heteronuclear single quantum coherence (HSQC), total correlation spectroscopy (TOCSY), and heteronuclear multiple bond correlation (HMBC). The methine, α‐methyl, and carbonyl carbon resonances were found to be sequence sensitive. The signals obtained were broad because of the restricted rotation of bulky carbazole group and the quadrupolar effect of nitrogen present in carbazole moiety. Glass transition temperatures (T_g) were determined by differential scanning calorimetry and were found to be characteristic of copolymer composition. As the N‐acryloylcarbazole content increases, the T_g increases from 378.3 K for poly(methyl methacrylate) to 430.4 K for poly(N‐acryloylcarbazole). Variation in T_g with the copolymer composition were found to be in good agreement with theoretical values obtained from Johnston and Barton equations. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2667–2676, 2006     

Synthesis of well‐defined comb‐like amphiphilic copolymers with protonizable units in the pendent chains: 1. Preparation of narrow polydispersity copolymers of methyl methacrylate and 2‐hydroxyethyl methacrylate by atom‐transfer radical polymerization

Well‐defined methyl methacrylate (MMA) and 2‐(trimethylsiloxy)ethyl methacrylate (Pro‐HEMA) copolymers were prepared by atom‐transfer radical polymerization(ATRP), using CuCl/2,2′‐bipyridine as catalytic system and p‐toluenesulfonyl chloride as initiator. ATRP process of MMA and Pro‐HEMA was monitored by ¹H NMR, and the kinetic curves of the MMA/Pro‐HEMA copolymerization were plotted in terms of the ¹H NMR data. At low content of Pro‐HEMA in the feed composition, the copolymerization can be well controlled with the molecular weight, polydispersity and the monomer distribution in the copolymer chain. With the increase of Pro‐HEMA content in the feed mixture, the composition of the final copolymer deviates from the composition of the feed mixture gradually, and gradient copolymers of MMA/Pro‐HEMA can be obtained. Through the hydrolysis process, well‐defined copolymers of MMA/HEMA were obtained from poly(MMA/Pro‐HEMA). Copyright © 2003 Society of Chemical Industry     

Copolymerization of N‐(4‐carboxyphenyl) itaconimide or N‐(4‐carboxyphenyl) itaconamic acid with methyl methacrylate

This paper describes the synthesis and characterization of N‐(4‐carboxyphenyl) itaconamic acid (CPA) and N‐(4‐carboxyphenyl) itaconimide (CPI) obtained by reacting itaconic anhydride with p‐aminobenzoic acid. Structural and thermal characterization of CPA and CPI was done using ¹H‐NMR, FTIR, and differential scanning calorimetry (DSC). Copolymerization of CPA or CPI with methyl methacrylate (MMA) in solution was carried out at 60 °C using azobisisobutyronitrile as an initiator and dimethyl acetamide or THF as solvent. Feed compositions having varying mole fractions of CPA or CPI ranging from 0.05–0.20 or 0.1–0.5 were taken to prepare copolymers. Copolymerizations were terminated at low percentage conversion. Structural characterization of copolymers was done by ¹H‐NMR and elemental analysis. Copolymer composition was determined using percentage nitrogen content. The reactivity ratios were r₁ (MMA) = 0.68 ± 0.06 and r₂ (CPI) = 0.46 ± 0.06. The intrinsic viscosity [η] was determined using an Ubbelohde suspension level viscometer. [η] decreased with increasing mole fraction of N‐(p‐carboxyphenyl) itaconimide or N‐(p‐carboxyphenyl) itaconamic acid in copolymers. Glass transition temperature and thermal stability of the copolymers were determined using DSC and thermogravimetric analysis, respectively. The glass transition temperature (T_g) as determined from DSC scans increased with increasing amounts of CPA or CPI in copolymers. A significant improvement in the char yield was observed upon copolymerization. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1909–1915, 2005     

Two‐dimensional NMR studies of styrene/n‐butyl acrylate copolymers synthesized by atom transfer radical polymerization

Copolymers of styrene and n‐butyl acrylate were prepared by atom transfer radical polymerization (ATRP) using CuBr/N,N,N′,N′,N″‐pentamethyl‐diethylenetriamine as catalyst and Methyl 2‐bromopropionate as initiator. The polydispersity of the copolymers is quite low (1.1–1.3). ¹³C {¹H} NMR spectra of these copolymers show that the methylene and methine signals of the main chain are compositional sensitive and highly overlapped. Even the distortionless enhancement by polarization transfer (DEPT) was not able to assign the complex and overlapping signals. Assignments of the various resonance signals were done with the help of heteronuclear single quantum coherence (HSQC), total correlation spectroscopy (TOCSY), and heteronuclear multiple bond correlation (HMBC) experiments. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

Synthesis of two‐end‐functionalized copolymer of styrene and methyl methacrylate via living radical polymerization

The random copolymers (HO‐P(St‐r‐MMA)‐COOH) of styrene (St) and methyl methacrylate (MMA) with hydroxyl group at one end and carboxyl group at another end were synthesized by nitroxide‐mediated living radical polymerization initiated by 4,4′‐azobis(4‐cyanovaleric acid) (ACVA) and 4‐hydroxyl‐2,2,6,6–tetramethylpiperidineoxyl (TEMPO‐OH). The experimental results have shown that all synthesized copolymers have narrow molecular weight distribution. The conversion of monomers and the molecular weight of copolymer increase with polymerization time. Thus, a copolymerization mechanism containing living radical polymerization is suggested. The use of this method permits the copolymer with two functional chain ends and controllable molecular weight as well as low molecular weight distribution. X‐ray photoelectron spectroscopy result shows that the synthesized copolymers can be tethered on the surface of silicon wafer through the reaction between the hydroxyl end of the copolymer and native oxide layer on the wafer. In addition, an organic/inorganic hybrid surface has achieved by treating copolymer tethered Si‐substrates with SiCl₄ vapor. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3118–3122, 2006     

Synthesis of methyl methacrylate and N‐aryl itaconimide block copolymers via atom‐transfer radical polymerization

The paper describes the synthesis of block copolymers of methyl methacrylate (MMA) and N‐aryl itaconimides using atom‐transfer radical polymerization (ATRP) via a poly(methyl methacrylate)–Cl/CuBr/bipyridine initiating system or a reverse ATRP AIBN/FeCl₃·6H₂O/PPh₃ initiating system. Poly(methyl methacrylate) (PMMA) macroinitiator, ie with a chlorine chain‐end (PMMA‐Cl), having a predetermined molecular weight (M_n = 1.27 × 10⁴ g mol^?1) and narrow polydispersity index (PDI = 1.29) was prepared using AIBN/FeCl₃·6H₂O/PPh₃, which was then used to polymerize N‐aryl itaconimides. Increase in molecular weight with little effect on polydispersity was observed on polymerization of N‐aryl itaconimides using the PMMA‐Cl/CuBr/Bpy initiating system. Only oligomeric blocks of N‐aryl itaconimides could be incorporated in the PMMA backbone. High molecular weight copolymer with a narrow PDI (1.43) could be prepared using tosyl chloride (TsCl) as an initiator and CuBr/bipyridine as catalyst when a mixture of MMA and N‐(p‐chlorophenyl) itaconimide in the molar ratio of 0.83:0.17 was used. Thermal characterization was performed using differential scanning calorimetry (DSC) and dynamic thermogravimetry. DSC traces of the block copolymers showed two shifts in base‐line in some of the block copolymers; the first transition corresponds to the glass transition temperature of PMMA and second transition corresponds to the glass transition temperature of poly(N‐aryl itaconimides). A copolymer obtained by taking a mixture of monomers ie MMA:N‐(p‐chlorophenyl) itaconimide in the molar ratio of 0.83:0.17 showed a single glass transition temperature. Copyright © 2005 Society of Chemical Industry     

Characterization of unsaturated polyester and alkyd resins using one‐ and two‐dimensional NMR spectroscopy

One‐ (1D) and two‐dimensional (2D) ¹H‐ and ¹³C‐NMR spectroscopy was used to characterize polyester and alkyd resins used in the coatings industry. The wealth of chemical composition information of the ¹H‐ and ¹³C‐NMR 1D spectra of the resins is revealed through 2D NMR experiments that spread chemical shifts in two dimensions, thus facilitating the peak assignment of the various components of the resins. It is shown that the types of polyols, acids, and vegetable oils used to modify the resins can be efficiently traced by NMR spectroscopic techniques. Information on the quantitative composition of the resins and especially the abundance of unsaturated fatty acid double bonds, which influences resin dryability and hardness, can be easily extracted from the ¹H‐NMR spectra upon successful assignment. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1881–1888, 2003