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).     

Emulsion atom transfer radical block copolymerization of 2‐ethylhexyl methacrylate and methyl methacrylate

The emulsion atom transfer radical block copolymerization of 2‐ethylhexyl methacrylate (EHMA) and methyl methacrylate (MMA) was carried out with the bifunctional initiator 1,4‐butylene glycol di(2‐bromoisobutyrate). The system was mediated by copper bromide/4,4′‐dinonyl‐2,2′‐bipyridyl and stabilized by polyoxyethylene sorbitan monooleate. The effects of the initiator concentration and temperature profile on the polymerization kinetics and latex stability were systematically examined. Both EHMA homopolymerization and successive copolymerization with MMA proceeded in a living manner and gave good control over the polymer molecular weights. The polymer molecular weights increased linearly with the monomer conversion with polydispersities lower than 1.2. A low‐temperature prepolymerization step was found to be helpful in stabilizing the latex systems, whereas further polymerization at an elevated temperature ensured high conversion rates. The EHMA polymers were effective as macroinitiators for initiating the block polymerization of MMA. Triblock poly(methyl methacrylate–2‐ethylhexyl methacrylate–methyl methacrylate) samples with various block lengths were synthesized. The MMA and EHMA reactivity ratios determined by a nonlinear least‐square method were ～0.903 and ～0.930, respectively, at 70 °C. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1914–1925, 2006     

Novel activated acrylates: synthesis, characterization and the reactivity ratios of 4-acetamidophenyl acrylate copolymers with methyl methacrylate and glycidyl methacrylate

A new functional activated acrylate, 4-acetamidophenyl acrylate (APA) was synthesized and characterized by IR, 1H- and 13C-NMR and mass spectra. Homo and copolymers of APA with MMA and GMA were prepared by free radical polymerization. All the copolymer compositions have been determined by 1H-NMR and the reactivity ratios of the monomer pairs have been evaluated. APA (r₁): 1.099 and MMA (r₂): 1.210 for copoly(APA-MMA) system. APA (r₁): 0.648 and GMA (r₂): 1.30 for copoly(APA-GMA) system. Thermal stability and molecular weights of the copolymers were reported.     

Reactivity ratios for the oxidative copolymerizations of indene with methyl methacrylate and methacrylonitrile

The copolyperoxides of indene with methyl methacrylate and methacrylonitrile have been synthesized by the free-radical-initiated oxidative copolymerization of indene and the monomers. The compositions of copolyperoxides, obtained from 1H and 13C NMR spectra, have been utilized to determine the reactivity ratios. The reactivity ratios indicate that the copolyperoxides contain a large proportion of the indene units in random placement. Thermal degradation studies of the copolyperoxides by differential scanning calorimetry and electron-impact mass spectroscopy support alternating peroxide units in the copolyperoxide chain. The energy of activation for thermal degradation suggests that the degradation is controlled by the dissociation of the peroxide (-O-O-) bonds in the copolyperoxide chain. The flexibility of copolyperoxide in terms of glass transition temperature (T_g) has also been examined.     

Ambient temperature living radical copolymerization of styrene and methyl methacrylate with sodium hypophosphite as reducing agent

A facile, safe and economical reducing agent, sodium hypophosphite(Na H2PO2·H2O), has been successfully employed for ambient temperature living radical copolymerization of styrene(St) and methyl methacrylate(MMA). Such effective reducing agent significantly improved the reactivity of low reactive St monomers during the copolymerization, where the reactivity ratios of St and MMA were determined to be 0.50 and 0.36 by Finemann-Ross method. Thus the copolymerizations proceeded fast and showed typical living/controlled features, as evidenced by pseudo first-order kinetics of polymerization, linear increase in molecular weight versus monomer conversion, and low polydispersity index values. Effects of the concentration of reducing agent and the monomer feed ratio on the copolymerization were investigated in detail. Furthermore, gel permeation chromatography and 1H-NMR analyses as well as chain extension experiments confirmed the high chain-end functionality of the resultant copolymer.     

Ambient temperature Atom Transfer Radical copolymerization of tetrahydrofurfuryl methacrylate and methyl methacrylate: Reactivity ratio determination

Tetrahydrofurfuryl methacrylate (THFMA), a heterocyclic monomer was polymerized by ambient temperature Atom Transfer Radical Polymerization (AT ATRP) using CuX/PMDETA/EBiB system. THFMA was found to undergo very rapid polymerization, in bulk. For a target DP > 200, bulk polymerization results in cross-linking as evidenced by (CH₂)_n,wag peaks (IR spectroscopy). Atom Transfer Radical copolymerization (ATRcP) of THFMA with MMA was performed and the reactivity ratios were calculated from the copolymer composition, as determined by ¹H NMR, using Fineman–Ross and Kelen–Tudos methods. The reactivity ratios determined for ATRP were found to be significantly different from the literature values for conventional free radical polymerization (CFRP). This may be due to the coordination of copper catalytic system with the oxygen atom of the tetrahydrofurfuryl group that could lead to the variation in reactivity ratios. ¹H NMR evidence for catalyst–monomer interaction is also provided.     

Ruthenium carborane complexes in the controlled radical polymerization of methyl methacrylate

New initiators based on closo-and exo-nido-ruthenacarboranes with phosphine and diphosphine ligands were proposed as chain growth regulators. They allow conducting the controlled synthesis of poly(methyl methacrylate) under radical initiation conditions. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 85–89, January, 2006.     

Self-initiated atom transfer radical polymerization of methyl methacrylate in cyclohexanone

The self-initiated atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) in cyclohexanone (CHO) in the presence of CuCl₂/N,N,N′,N″,N″-pentamethyldiethylenetriamine (PMDETA) is reported. The linear semilogarithmic plot of ln([M]₀/[M]) vs time, the linear increase of number-average molecular weight (M_n) with conversion, and rather narrow molecular weight distributions (MWDs) have been observed, which are in agreement of the characteristics of living/controlled polymerization. The NMR spectrum revealed the existence of terminal chlorine. The chain extension further proved the living characteristic. The polymerization can only be successful using CHO as the solvent, and is well controlled at the temperature as low as 50 °C. The effects of ligand, solvent, temperature and monomer to catalyst ratio are all discussed.     

Homopolymerization and copolymerization of isocyanatoethyl methacrylate

This article describes the homopolymerization of isocyanatoethyl methacrylate (IEM) and its copolymerization with methyl methacrylate (MMA) in acetonitrile in the presence of 2,2′‐azobisisobutyronitrile. The constant characteristic of IEM polymerizability (k_p²/k_te = 128 × 10^?3 L mol^?1 s^?1, where k_p is the propagation constant and k_te is the termination constant) was determined. The study of IEM reactivity toward MMA gave ratios of 0.88 and 1.20 for IEM and MMA, respectively. The physicochemical properties of the IEM homopolymer and IEM/MMA copolymers were also studied. The glass‐transition temperature of poly(isocyanatoethyl methacrylate) was found to be 47 °C. From the thermogravimetric analysis of the weight‐loss percentage corresponding to the first wave of the thermogram, it was shown that the degradation mechanism of the IEM/MMA copolymers started from the isocyanate group. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4762–4768, 2006     

Synthesis of 4-arm methyl methacrylate star polymer by atom transfer radical polymerization

The synthesis of 4-arm methyl methacrylate star polymer had been achieved successfully by atom transfer radical polymerization using CuCl as catalyst, 2, 2′-bipyridyl as ligand and pentaerythritol tetrakis (2-bromoisobutyrate) as the initiator. The star polymer was characterized by ¹H-NMR and GPC, by which the precise 4-arm structure of the PMMA was confirmed. __________ Translated from Journal of Shaanxi Normal University (Natural Science Edition), 2008, 36(2) (in Chinese)     

Copolymerization of butyl vinyl ether and methyl methacrylate by combination of radical and radical promoted cationic mechanisms

Butyl vinyl ether (BVE) and methyl methacrylate (MMA) mixtures were polymerized by using free radical initiators in conjunction with a cationic initiator such as diphenyl iodonium salt. Polymerization mechanism involves free radical polymerization of MMA which is switched to cationic polymerization of BVE by addition of growing poly(MMA) radicals to BVE and subsequent oxidation of electron donating polymeric radicals to the corresponding cations by iodonium ions. Two representative bifunctional monomers, ethylene glycol divinyl ether (EGDVE) and ethylene glycol dimethacrylate (EGDMA) were also used together with MMA and BVE, respectively, in photo and thermal crosslinking polymerizations. Vinyl ether and methacrylate type monomers can successfully be copolymerized by this double-mode polymerization under photochemical conditions.     

New efficient boron-containing initiators of methyl methacrylate radical polymerization

An efficient method for methyl methacrylate radical polymerization by tri-n-propyl-, triisopropyl-, and triisobutylborane ammonia complexes, including the addition of a boron-containing initiating agent into the monomer in air, was developed. An advantage of this method is that the reaction occurs at room temperature, requires no peroxide components, and leads to polymers with enhanced thermal stability.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2120–2125, October, 2004.     

Statistical copolymers of methyl methacrylate and 2‐methacryloyloxyethyl ferrocenecarboxylate: Monomer reactivity ratios,thermal and electrochemical properties

Statistical copolymers of methyl methacrylate (MMA) with 2‐methacryloyloxyethyl ferrocenecarboxylate (MAEFC) were prepared by free radical polymerization. The reactivity ratios were estimated using the Fineman‐Ross, inverted Fineman‐Ross, Kelen‐Tüdos, and extended Kelen‐Tüdos graphical methods. Structural parameters of the copolymers were obtained by calculating the dyad monomer sequence fractions and the mean sequence length. The glass‐transition temperature (T_g) values of the copolymers were measured and examined by means of several theoretical equations, allowing the prediction of these T_g values. The thermal degradation behavior of the copolymers was also studied and compared with the respective homopolymers. Cyclic voltammetry was employed to study the electrochemical properties of the copolymers. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Polymeric microspheres by radiation copolymerization of acrolein and various monomers at low temperatures

The preparation of polymeric microspheres having aldehyde groups by radiation polymerization of acrolein solution containing various monomers at low temperatures was studied, in which the monomer solution was dispersed with polyvinyl alcohol in order to obtain monomeric microspheres and then irradiated. The particle size of the microspheres from acrolein — 2-hydroxyethyl methacrylate system varied with polymerization and dispersion condition, in which the particle size increase of the concentration of 2-hydroxy ethyl methacrylate and its particle size distribution was broadened. In acrolein — polyethyleneglycol dimethacrylate system, the effect of the molecular structure of monomers on the particle size was studied, and it was found that the particle size decreased with number of oxyethylene units in monomers.     

Radical copolymerization of 2-vinyl pyridine and oligo(ethylene glycol) methyl ether methacrylates: Monomer reactivity ratios and thermal properties

Statistical copolymers of 2-vinylpyridine (VP) with oligo(ethylene glycol) methyl ether methacrylates of two different molecular weights (300 g/mol (OEGMA₃₀₀) and 1100 g/mol (OEGMA₁₁₀₀)), were prepared by free radical polymerization. The reactivity ratios of these two sets of monomers were estimated using the Finemann–Ross, the inverted Finemann–Ross and the Kelen–Tüdos graphical methods. Structural parameters of the copolymers were obtained by calculating the dyad monomer sequence fractions and the mean sequence length. The effect of the length of the oligo(ethylene glycol) group on the copolymer structure is discussed. The glass-transition temperature (T_g) values of the VP copolymers with OEGMA₃₀₀ were measured and examined in the frame of several theoretical equations, allowing the prediction of these T_g values. The copolymers of VP with OEGMA₁₁₀₀ exhibited the characteristic melting endotherm, due to the crystallinity of the methacrylate sequences and glass transition temperatures attributed to the PVP sequences.     

Low- and high-conversion studies of the free radical copolymerization of 2-hydroxyethyl methacrylate with styrene in N,N′-dimethylformamide solution

2-Hydroxyethyl methacrylate (HEMA) and styrene (S) have been copolymerized in a 3 mol · L⁻¹N,N′-dimethylformamide (DMF) solution using 2,2′azobis (isobutyronitrile) (AIBN) as an initiator over a wide composition and conversion range. From low-conversion experiments and ¹H-NMR analysis, the monomer reactivity ratios were determined according to the Mayo–Lewis terminal model. The comparison of the obtained results with those previously reported for copolymerization in bulk and in toluene reveals a relatively small but noticeable solvent effect that can be qualitatively explained by the bootstrap model. Cumulative copolymer composition as a function of conversion is satisfactorily described by the integrated Mayo–Lewis equation; overall copolymerization rate increases with increasing the HEMA/S ratio, and individual monomer conversion is closely related to the monomer molar fraction in the feed. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 2941–2948, 1999