Synthesis of well‐defined glycidyl methacrylate based block copolymers with self‐activation and self‐initiation behaviors via ambient temperature atom transfer radical polymerization

Well‐defined glycidyl methacrylate (GMA) based di‐ and triblock copolymers, with self‐activation and self‐initiation behaviors by incorporation of 2‐(diethylamino) ethyl methacrylate (DEA) blocks, were synthesized via ambient temperature atom transfer radical polymerization (ATRP). The stability of the GMA pendant oxirane rings in tertiary amine environments at ambient temperature was investigated. More importantly, both self‐activation behavior in oxirane ring opening addition reaction and self‐initiation behavior in post‐cure oxirane ring opening crosslinking of these block copolymers were evidenced by ¹H NMR studies. The results demonstrated that the reactivity of pendent oxirane rings was strongly dependant on the nucleophilicity and steric hindrance of tertiary amine moieties and temperature. This facilitated the synthesis of well‐defined block copolymers of GMA and DEA via sequential monomer addition ATRP, particularly for polymerization of GMA monomer at ambient temperature. Moreover, these one‐component GMA based block polymers have novel self‐activation and self‐initiation properties, rendering some potential applications in both enzyme immobilization and GMA‐based thermosetting materials. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2947–2958, 2007     

Atom transfer radical copolymerization of glycidyl methacrylate and allyl methacrylate, two functional monomers

Bi-functional statistical copolymers, based on allyl methacrylate (AMA) and glycidyl methacrylate (GMA), were synthesized via atom transfer radical polymerization (ATRP). The polymerization reactions were carried out in a diphenyl ether solution at low temperature, 50 °C, using ethyl 2-bromoisobutyrate (EBrIB) as an initiator, and copper chloride with N,N,N′,N′′,N′′-pentamethyldiethylenetriamine (PMDETA) as the catalyst. Different aspects of the copolymerization, such as the kinetic behaviour, crosslink density and gel fraction were studied. The sol fractions of the synthesized copolymers were characterized by size exclusion chromatography (SEC) and nuclear magnetic resonance (NMR) spectroscopy. The reactivity ratios were calculated from the copolymer composition, determined by ¹H NMR, and using the extended Kelen-Tüdös method. Values of 0.82 ± 0.04 and 1.22 ± 0.03 were obtained for AMA and GMA, respectively. The copolymer composition as a function of conversion degree for the different monomer molar fractions in the feed agreed with the theoretical values calculated from the Mayo-Lewis terminal model (MLTM).     

Synthesis, spectral and thermal properties of homo- and copolymers of 2-[(5-methylisoxazol-3-yl)amino]-2-oxo-ethyl methacrylate with styrene and methyl methacrylate and determination of monomer reactivity ratios

The methacrylate monomer, 2-[(5-methylisoxazol-3-yl)amino]-2-oxo-ethyl methacrylate (IAOEMA), was synthesized by reacting 2-chloro-N-(5-methylisoxazol)acetamide dissolved in acetonitrile with sodium methacrylate in the presence of triethylbenzylammoniumchloride (TEBAC). The free-radical-initiated copolymerization of IAOEMA, with styrene (ST) and methyl methacrylate (MMA) was carried out in dimethylsulphoxide (DMSO) solution at 65 °C using 2,2^′-azobisisobutyronitrile (AIBN) as an initiator with different monomer-to-monomer ratios in the feed. The monomer (IAOEMA) and copolymers were characterized by FTIR, ¹H- and ¹³C-NMR spectral studies. The copolymer composition was evaluated by nitrogen content in polymers led to the determination of reactivity ratios. The reactivity ratios of the monomers were determined by the application of Fineman-Ross and Kelen-Tüdös methods. The analysis of reactivity ratios revealed that ST and MMA are more reactive than IAOEMA, and copolymers formed are statisticalle in nature. The molecular weights (M_w and M_n) and polydispersity index of the polymers were determined using gel permeation chromagtography. Glass transition temperatures of the copolymers were found to increase with an increase in the mole fraction of IAOEMA in the copolymers. The apparent thermal decomposition activation energies (E_d) were calculated by Ozawa method using the SETARAM Labsys TGA thermobalance.     

Preparation of amphiphilic statistical copolymers of 2‐hydroxyethyl methacrylate with 2‐diethylaminoethyl methacrylate,precursors of water‐soluble copolymers

Statistical copolymers of 2‐hydroxyethyl methacrylate (HEMA) and 2‐diethylaminoethyl methacrylate (DEA) were synthesized at 50 °C by free‐radical copolymerization in bulk and in a 3 mol L^?1 N,N′‐dimethylformamide solution with 2,2′‐azobisisobutyronitrile as an initiator. The solvent effect on the apparent monomer reactivity ratios was attributed to the different aggregation states of HEMA monomer in the different solvents. The copolymers obtained were water‐insoluble at a neutral pH but soluble in an acidic medium when the molar fraction of the DEA content was higher than 0.5. The quaternization of DEA residues increased the hydrophilic character of the copolymers, and they became water‐soluble at a neutral pH when the HEMA content was lower than 0.25. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2427–2434, 2002     

Further Studies on the Anionic Copolymerization of Styrene and Glycidyl Methacrylate in Toluene

Sequential anionic copolymerization of styrene and glycidyl methacrylate (GMA) was performed with the protection of argon under normal pressure, where styrene, GMA, toluene, THF, n-butyllithium and a small amount of lithium chloride (LiCl) were used as first monomer, second monomer, solvent, polar reagent, initiator and additive, respectively. Polystyrene-b-poly(glycidyl methacrylate) diblock copolymers (PS-b-PGMA) with well-defined structure and narrow molecular weight distribution were prepared by the copolymerization reaction of poly(styryl)lithium with GMA under certain temperatures. The copolymers were characterized using gel permeation chromatography (GPC), ¹H-NMR, ¹³C-NMR, thin layer chromatography (TLC) and hydrochloric acid-dioxane argentimetric methods. The effects of additives, copolymerization temperature and THF dosage on the copolymerization were studied. No chain transfer reaction of anionic polymerization of styrene in toluene was observed. Slightly broader molecular weight distribution of PS-b-PGMA was observed with the increase the GMA repeat units. Using THF/toluene blend solvent could reduce the polydispersity index (M _w /M _n ) and dissolve the copolymer better than toluene alone. Lower temperature (< -40°C) and LiCl are required to prepare PS-b-PGMA with narrower molecular weight distribution.     

Copolymers of 7-Methoxy-2-Acetyl Benzofuryl Methylmethacrylate With Styrene: Synthesis,Characterization, Reactivity Ratios and Determination of Kinetic Parameters With Thermogravimetric Analysis

The 7-methoxy-2-acetyl benzofuryl methylmethacrylate (MABMM) monomer was synthesized by reacting 7-methoxy-2-bromo acetyl benzofurane with sodium methacrylate in acetonitrile solvent at 70°C in the presence of triethylbenzylammoniumchloride (TEBAC). The monomer was characterized by FTIR, ¹H-and ¹³C-NMR spectral studies. Reactivity ratios for the copolymers 7-methoxy-2-acetyl benzofuryl methylmethacrylate (MABMM)-co- styrene (ST) are reported. Copolymers were prepared by free radical polymerization using 2,2′-azobisisobutyronitrile (AIBN) as an initiator at 70°C in 1,4-dioxane solution. FTIR, ¹H-and ¹³C-NMR spectral studies and gel permeation chromatography (GPC) were used the copolymer characterization. The monomer compositions in the copolymer were determined by elementel analyses and the reactivity ratios (ri) were calculated applying diverse linear methods, namely Finemann-Ross (FR) and Kelen-Tüdös (KT) and the nonlinear error invariable model method of a computer program RREVM. By using the latter pr°Cedure, the values of the reactivity ratios were estimated as 2.74 and 0.69 for the system MABMM (1) and ST (2), respectively. These values suggest the formation of nearly-alternating copolymers in the systems. Molecular weights were determined by gel permeation chromatography (GPC). The polydispersity indices of the polymers determined using suggest a strong tendency for chain termination by disproportionation. The glass transition temperature of the polymers were investigated by Shimadzu DSC-60 and the apparent thermal decomposition activation energies (E_d) were calculated by the Ozawa method using the Perkin-Elmer TGA thermobalance, respectively. Tg increases when the concentration of polar monomer (MABMM) in the copolymer increases. It was observed that thermal stabilities of copolymers increased with increasing of MABMM content in copolymers.     

Determination of copolymer composition by Raman spectroscopy

The application of laser-Raman spectroscopy to the analysis of copolymers of glycidyl methacrylate (GMA) with methyl methacrylate (MMA) and styrene is discussed. For both copolymer systems the line near 1451 cm^?1, assigned to the methylene bending mode, was found to be a useful reference. Lines characteristic of each monomer were identified. The intensities of these lines were found to be linearly related to the composition of the copolymers when normalized against the 1451 cm^?1 reference. The line near 1730 cm^?1, assigned to the carbonyl stretching mode, was also found to be a useful reference for the copolymers of methyl methacrylate and glycidyl methacrylate.     

Studies on the copolymerisation of N-isopropyl-acrylamide with glycidyl methacrylate

The paper describes the homopolymerisation and copolymerisation of N-isopropyl acrylamide (NIPAM) with glycidyl methacrylate (GMA) in solution at 60°C using azobisisobutyronitrile (AIBN) as an initiator and dioxan as solvent. Copolymers were synthesized by varying the mol fraction of GMA in the initial feed from 0.025-0.125. All the polymerization reactions were terminated at low % conversion (10-15%) and the copolymer composition was determined by measuring the epoxy content. Percent epoxy content was determined by titration method using pyridine-HCl mixture. The reactivity ratios determined using Fineman-Ross method were found to be 0.94±0.05 (r₁, NIPAM) and 1.05±0.08 (r₂, GMA). All the polymers have high molecular weights with wide molecular weight distribution as determined by gel permeation chromatography (GPC) i.e. M_n in the range of 3.7 x 10⁴ - 7.8 x 10⁴ and M_w in the range of 1.2 x 10⁵ - 4.1 x 10⁵ with a polydispersity index in the range of 2.3-5.3. Lower critical solution temperature (LCST) of NIPAM homopolymer and copolymers was determined by recording DSC scans of polymers in aqueous solution. Incorporation of GMA in the poly(NIPAM) backbone resulted in a decrease in the LCST.     

Characterization and optimization of poly(glycidyl methacrylate-co-styrene) synthesized by atom transfer radical polymerization

Styrene (S) and glycidyl methacrylate (GMA) copolymers were synthesized by atom transfer radical polymerization (ATRP) under different conditions. The effect of initiators, ligands, solvents, and temperature to the linear first-order kinetics and polydispersity index (PDI) was investigated for bulk polymerization. First-order kinetics was observed between linearly increasing molecular weight versus conversion and low polydispersities (PDI) were achieved for ethyl 2-bromo isobutyrate (EBiB) as an initiator and N,N′,N′,N″,N″-pentamethyldiethylenetriamine (PMDETA)/CuBr as a catalyst. The copolymers with different compositions were synthesized using different in-feed ratios of monomers. Copolymers composition was calculated from ¹H NMR spectra which were further confirmed by quantitative ¹³C{¹H} NMR spectra. The monomer reactivity ratios were obtained with the help of Mayo-Lewis equation using genetic algorithm method. The values of reactivity ratios for glycidyl methacrylate and styrene monomers are r_G = 0.73 and r_S = 0.42, respectively.     

Synthesis,characterization, and bulk properties of amphiphilic copolymers containing fluorinated methacrylates from sequential copper‐mediated radical polymerization

The partly fluorinated monomers, 2,2,2‐trifluoroethyl methacrylate (3FM), 2,2,3,3,4,4,5,5‐octafluoropentyl methacrylate (8FM), and 1,1,2,2‐tetrahydroperfluorodecyl methacrylate (17FM) have been used in the preparation of block copolymers with methyl methacrylate (MMA), 2‐methoxyethyl acrylate (MEA), and poly(ethylene glycol) methyl ether methacrylate (PEGMA) by Atom Transfer Radical Polymerization. A kinetic study of the 3FM homopolymerization initiated with ethyl bromoisobutyrate and Cu(I)Br/N‐(n‐propyl)‐2‐pyridylmethanimine reveals a living/controlled polymerization in the range 80–110 °C, with apparent rate constants of 1.6 · 10⁻⁴ s⁻¹ to 2.9 · 10⁻⁴ s⁻¹. Various 3FM containing block copolymers with MMA are prepared by sequential monomer addition or from a PMMA macroinitiator in all cases with controlled characteristics. Block copolymers of 3FM and PEGMA resulted in block copolymers with PDI < 1.22, whereas block copolymers from 3FM and MEA have less controlled characteristics. The block copolymers based on MMA with 8FM and 17 FM have PDI's < 1.30. The glass transition temperatures of the block copolymers are dominated by the majority monomer, as the sequential monomer addition results in too short pure blocks to induce observable microphase separation. The thermal stability of the fluorinated poly((meth)acrylate)s in inert atmosphere is less than that of corresponding nonfluorinated poly((meth)acrylate)s. The presence of fluorinated blocks significantly increases the advancing water contact angle of thin films compared to films of the nonfluorinated poly((meth)acrylate)s. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 8097–8111, 2008     

Synthesis and Characterization of Novel Methacrylate Monomers Having Pendant Oxime Esters and Their Copolymerization with Styrene

New methacrylate monomers, 2‐{[(diphenylmethylene)amino]oxy}‐2‐oxoethyl methacrylate (DPOMA) and 2‐{[(1‐phenylethylidene)ami no]oxy}‐2‐oxoethyl methacrylate (MMOMA) were prepared by reaction of sodium methacrylate with diphenylmethanone O‐(2‐chloroacetyl) oxime and 1‐phenylethanone O‐(2‐chloroacetyl) oxime, respectively. They were obtained from a reaction of chloroacetyl chloride with benzophenone oxime or acetophenone oxime. The free‐radical‐initiated copolymerization of (DPOMA) and (MMOMA) with styrene (St) were carried out in 1,4‐dioxane solution at 65°C using 2,2‐azobisisobutyronitrile (AIBN) as an initiator with different monomer‐to‐monomer ratios in the feed. The monomers and copolymers were characterized by FTIR, ¹H‐ and ¹³C‐NMR spectral studies. The copolymer compositions were evaluated by nitrogen content in polymers. The reactivity ratios of the monomers were determined by the application of Fineman–Ross and Kelen–Tüdös methods. The molecular weights (M¯_w and M¯_n) and polydispersity index of the polymers were determined by using gel permeation chromatography. Thermogravimetric analysis of the polymers reveals that the thermal stability of the copolymers increases with an increase in the mole fraction of St in the copolymers. The activation energies of the thermal degradation of the polymers were calculated with the MHRK method. Glass transition temperatures of the copolymers were found to decrease with an increase in the mole fraction of DPOMA or MMOMA in the copolymers. The antibacterial and antifungal effects of the monomers and polymers were also investigated on various bacteria and fungi. The photochemical properties of the polymers were investigated by UV and FTIR spectra.     

Synthesis and characterization of a poly(GMA)‐graft‐poly(Z‐L‐lysine) graft copolymer with a rod‐like structure

This study applied the macromonomers and glycidyl methacrylate (GMA) to synthesize a series of the graft copolymers, poly(GMA)‐graft‐poly(Z‐L ‐lysine), and investigated the conformation of the graft copolymer. The graft copolymers were synthesized with different GMA monomer ratios (28 to 89%) and different degrees of polymerization (DP) (8 to 15) of the poly(Z‐L ‐lysine) side chain to analyze secondary structure relationships. Atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR), and both wide angle and small angle X‐ray scattering spectroscopy (WAXS, SAXS) were used to investigate the relationship between the microstructure and conformation of the graft copolymers and the different monomer ratios and side chain DP. In AFM images, n8‐G89 (the graft copolymer containing 89% GMA units and the macromonomer DP is 8) showed tiny and uniform rod‐like structures, and n14‐G43 (the graft copolymer containing 43% GMA units and the macromonomer DP is 14) showed uniform rod‐like structures. FTIR spectra of the graft copolymers showed that the variations of α‐helix and β‐sheet secondary structures in the graft copolymers relate to the monomer ratios of the graft copolymers. However, the X‐ray scattering patterns indicated that the graft copolymer conformations were mainly dependent on the poly(Z‐L ‐lysine) side chain length, and these results were completely in accordance with the AFM images. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4655–4669, 2009     

Copolymers of methyl methacrylate and fluoroalkyl methacrylates: Effects of fluoroalkyl groups on the thermal and optical properties of the copolymers

Fluoroalkyl methacrylates, 2,2,2‐trifluoroethyl methacrylate ( 1 ), hexafluoroisopropyl methacrylate ( 2 ), 1,1,1,3,3,3‐hexafluoro‐2‐methyl‐2‐propyl methacrylate ( 3 ), and perfluoro t‐butyl methacrylate ( 4 ) were synthesized. Homopolymers and copolymers of these fluoroalkyl methacrylates with methyl methacrylate (MMA) were prepared and characterized. With the exception of the copolymers of MMA and 2,2,2‐trifluoroethyl methacrylate ( 1 ), the glass transition temperatures (T_gs) of the copolymers were found to deviate positively from the Gordon‐Taylor equation. The positive deviation from the Gordon‐Taylor equation could be accounted for by the dipole–dipole intrachain interaction between the methyl ester group and the fluoroalkyl ester group of the monomer units. These T_g values of the copolymers were found to fit with the Schneider equation. The fitting parameters in the Schneider equation were calculated, and R² values, the coefficients of determination, were almost 1.0. The refractive indices of the copolymers, measured at 532, 633, and 839 nm wavelengths, were lower than that of PMMA and showed a linear relationship with monomer composition in the copolymers. 2 and MMA have a tendency to polymerize in an alternating uniform monomer composition, resulting in less light scattering. This result suggests that the copolymer prepared with an equal molar ratio of 2 and MMA may have useful properties with applications in optical devices. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4748–4755, 2008     

Novel methacrylate copolymers with fluorine containing: Synthesis, characterization, reactivity ratios, thermal properties and biological activity

New methacrylate based monomers 2-(4-benzoylphenoxy)-2-oxoethyl-2-methylacrylate (BOEMA), 2-(4-acetylphenoxy)-2-oxoethyl-2-methylacrylate (AOEMA), and 2-[(4-fluorophenyl)amino]-2-oxoethyl-2-methylacrylate (FPAMA), were synthesized first time. The free-radical-initiated copolymerization of AOEMA and BOEMA with FPAMA were carried out in 1,4-dioxane solution at 65 °C using 2,2′-azobisisobutyronitrile (AIBN) as an initiator with different monomer-to-monomer ratios in the feed. The monomers and copolymers were characterized by FTIR, ¹H NMR and ¹³C NMR spectral studies. The copolymer compositions were evaluated by nitrogen content in polymers. The reactivity ratios of the monomers were determined by the application of Fineman-Ross and Kelen-Tudos methods. The analysis of reactivity ratios revealed that BOEMA and AOEMA are less reactive than FPAMA, and copolymers formed are statistically in nature. The molecular weights ( and ) and polydispersity index of the polymers were determined using gel permeation chromatography. Thermogravimetric analysis of the polymers reveals that the thermal stability of the copolymers increases with an increase in the mole fraction of FPAMA in the copolymers. Glass transition temperatures of the copolymers were found to decrease with an increase in the mole fraction of FPAMA in the copolymers. The prepared homo and copolymers were tested for their antimicrobial activity against bacteria, fungi and yeast.     

Orthogonally functionalizable copolymers based on a novel reactive carbonate monomer

A novel N‐hydroxy succinimide‐based carbonate monomer that allows direct synthesis of polymers incorporating a reactive carbonate group in the side chain was synthesized. This new monomer was copolymerized with methyl methacrylate and poly(ethylene glycol) methylether methacrylate using free‐radical polymerization to obtain organo‐ and water‐soluble reactive copolymers. Copolymerization of the activated carbonate monomer with an azide‐containing monomer and N‐hydroxy succinimide‐containing activated ester monomer provided orthogonally functionalizable copolymers. The pendant reactive carbonate groups of the copolymers were functionalized with amines to obtain carbamates. Polymers capable of orthogonal functionalization could be selectively functionalized as desired using subsequent 1,3‐dipolar cycloaddition or amidation reactions. The novel monomer and the copolymers were characterized by ¹H‐NMR, ¹³C‐NMR, and infrared spectroscopy. The efficient stepwise orthogonal functionalization of the copolymers were examined via ¹H‐NMR spectroscopy. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

MONOMER REACTIVITY RATIO AND THERMAL PERFORMANCE OFα-METHYL STYRENE AND GLYCIDYL METHACRYLATE COPOLYMERS

<正>Synthesis and characterization of the copolymers(PAG) ofα-methyl styrene(AMS) and glycidyl methacrylate (GMA) are presented.The copolymers of PAG were characterized by gel permeation chromatography(GPC),Fourier transform infrared spectroscopy(FTIR),nuclear magnetic resonance(~1H-NMR) and thermogravimetery(TG).Based on the copolymer compositions determined by ~1H-NMR,the reactivity ratios of AMS and GMA were found to be 0.105±0.012 and 0.883±0.046 respectively by Kelen-Tüds method.TG revealed that thermal stability of the copolymers decreased with increasing the AMS content in the copolymers,which indicated that the degradation was mainly caused by the chain scission of AMS-containing structures.Under heating,the copolymers depolymerize at their weak bonds and form chain radicals, which could further initiate other chemical reactions.     

Copolymerization of 4‐Propanoylphenyl Acrylate with Methyl Methacrylate: Synthesis,Characterization and Reactivity Ratios

The new acrylic monomer 4‐propanoylphenyl acrylate (PPA) was synthesized and copolymerized with methyl methacrylate (MMA) in methyl ethyl ketone at 70±1°C using benzoyl peroxide as a free radical initiator. The copolymers were characterized by FT‐IR, ¹H‐NMR and ¹³C‐NMR spectroscopic techniques. The compositions of the copolymers were determined by ¹H‐NMR analysis. The reactivity ratios of the monomers were determined using Fineman‐Ross (r₁=0.5535 and r₂=1.5428), Kelen‐Tüdös (r₁=0.5307 and r₂=1.4482), and Ext. Kelen‐Tüdös (r₁=0.5044 and r₂=1.4614), as well as by a nonlinear error‐in‐variables model (EVM) method using a computer program, RREVM (r₁=0.5314 and r₂=1.4530). The solubility of the polymers was tested in various polar and non‐polar solvents. The elemental analysis was determined by a Perkin‐Elmer C‐H analyzer. The molecular weights (M_w and M_n) of the copolymers were determined by gel permeation chromatography. Thermogravimetric analysis of the polymers reveals that the thermal stability of the copolymers increases with an increase in the mole fraction of MMA in the copolymers. Glass transition temperatures of the copolymers were found to increase with an increase in the mole fraction of MMA in the copolymers.     

Synthesis and characterization of random copolymers of (2,2-dimethyl-1,3-dioxolan-4-yl)methyl methacrylate and 2,3-dihydroxypropyl methacrylate

Poly[(2,2-dimethyl-1,3-dioxolan-4-yl)methyl methacrylate)] [poly(solketal methacrylate) (PSMA)] was synthesized by free radical polymerization. By partial hydrolysis of the acetal group, random copolymers of SMA with 2,3-dihydroxypropyl methacrylate (DHPMA) were synthesized whereas complete cleavage lead to poly(2,3-dihydroxypropyl methacrylate) (PDHPMA). The copolymer composition was determined by ¹H NMR spectroscopy. FTIR spectroscopy indicates the synthesis of random copolymers with different degrees of hydrogen bonding as measured by a shift of the OH vibration bands. The glass transition temperature of the random copolymers increases linearly with increasing DHPMA content, resulting in a positive deviation from the Fox equation. The thermal degradation of both homopolymers and their random copolymers has been studied. Finally, the solution behaviour of the copolymers and PDHPMA in water studied by dynamic light scattering showed a strong tendency of the polymer chains to form clusters in the size range of 15-62 nm. The size and the kind of associating interactions within the clusters strongly depend on the copolymer composition.     

Homopolymer and copolymers of 4-nitro-3-methylphenyl methacrylate with glycidyl methacrylate: Synthesis, characterization, monomer reactivity ratios and thermal properties

The novel methacrylic monomer, 4-nitro-3-methylphenyl methacrylate (NMPM) was synthesized by reacting 4-nitro-3-methylphenol dissolved in ethyl methyl ketone (EMK) with methacryloyl chloride in the presence of triethylamine as a catalyst. The homopolymer and copolymers of NMPM with glycidyl methacrylate having different compositions were synthesized by free radical polymerization in EMK solution at 70 ± 1 °C using benzoyl peroxide as free radical initiator. The homopolymer and the copolymers were characterized by FT-IR, ¹H NMR and ¹³C NMR spectroscopic techniques. The solubility tests were tested in various polar and non-polar solvents. The molecular weight and polydispersity indices of the copolymers were determined using gel permeation chromatography. The glass transition temperature of the copolymers increases with increase in NMPM content. The thermogravimetric analysis of the polymers performed in air showed that the thermal stability of the copolymer increases with NMPM content. The copolymer composition was determined using ¹H NMR spectra. The monomer reactivity ratios were determined by the application of conventional linearization methods such Fineman-Ross (r₁ = 1.862, r₂ = 0.881), Kelen-Tudos (r₁ = 1.712, r₂ = 0.893) and extended Kelen-Tudos methods (r₁ = 1.889, r₂ = 0.884).     

Studies of methyl methacrylate–glycidyl methacrylate copolymers: Copolymerization to low molecular weights and modification by ring-opening reaction of epoxy side groups

The copolymerization of methyl methacrylate (MMA) with glycidyl methacrylate (GMA) at 60°C with 2,2′-azobisisobutyronitrile (AIBN) as radical initiator and in the presence of thiophenol (TP) as chain-transfer agent has been investigated. Monomer reactivity ratios for MMA and GMA are found to be r₁ (MMA) = 0.80 ± 0.015 and r₂ (GMA) = 0.70 ± 0.015, from which Q and e values are calculated to be 0.68 and ?0.36 for GMA. The initial rate of copolymerization R_p at 60°C with AIBN (0.02 mole/l.) and TP (0.1, 0.01 mole/l.) were found to increase nonlinearly with increasing GMA concentration in the monomer feed. Homopolymerizations of MMA and GMA monomers were studied in the presence and in the absence of thiophenol. The values of δ (= k_t^1/2/k_p) for MMA and GMA were determined to be 10.25 and 3.00 (mole-sec/l.)^1/2, respectively. Using the values r₁ (MMA), r₂ (GMA), δ₁ (MMA), δ₂ (GMA), and R_p, the cross-termination constants ? for MMA–GMA monomers were determined (average value ? = 0.42). The increase in R_p values with increasing GMA content has been attributed to the cross-termination of MMA–GMA radicals. The transfer constant of TP has also been determined for GMA and found to be 1.00. A MMA–GMA copolymer of low molecular weight, containing 2.01% of oxirane oxygen, was modified by opening of the oxirane ring of GMA by reaction with diethanolamine (DEA). The reaction was carried out at 70 ± 1°C, the copolymer content of epoxy groups and the amine being assumed to be in the molar ratio of 1:4. Addition of a hydrogen-bond acceptor like nitrobenzene decreases, while addition of a hydrogen-bond donor like phenol increases the rate of epoxy ring opening with DEA. This indicates that a hydrogen-bonded intermediate is involved in this reaction and that it weakens the epoxy ring and enhances the rate of its opening with DEA. From the studies of the conversion rates, existence of a “nonspecific” side reaction has been shown which involves the reaction of the terminal epoxy groups of the copolymer and the hydroxyl groups of DEA or formed in the reaction with DEA (involves a chain coupling). DEA can be trifunctional in this reaction. This has been further confirmed from the increase of number-average molecular weights M?_n of the copolymers resulting from this coupling and the nitrogen content in the copolymers after modification with DEA.