Polymerization of acrylamide initiated with electrogenerated cerium (IV) in the presence of EDTA

Polymerization of acrylamide was carried out with cerium (IV)-EDTA redox initiator system with and without electrolysis. The effect of temperature, time, cerium (IV), and EDTA concentrations on the polymerization yield and molecular weight were studied and compared with electrolytic conditions. At low concentrations of cerium (IV) the electrolytic method continuously supplying Ce (IV) from Ce (III) has an advantage over the nonelectrolytic method for which polymerization did not occur under these conditions. A possible polymerization mechanism is suggested.     

Graft copolymerization of methyl methacrylate onto starch using a Ce(IV)–glucose initiator system

Graft copolymerization of methyl methacrylate onto starch was carried out in aqueous medium using Ce(IV)–glucose initiator in the temperature range 40–60°C. Effects of concentration of Ce(IV), glucose, H₂SO₄, monomer, and starch on grafting were investigated. Percentages of grafting were evaluated and compared. The overall energy of activation was calculated from the effects of time and temperature of polymerization. The reaction mechanism was also discussed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 981–990, 2004     

Ce(IV)‐induced graft copolymerization of methacrylic acid on electrospun polysulphone nonwoven fiber membrane

Ce(IV)‐induced graft copolymerization of methacrylic acid (MAA) on polysulphone (PSU) surface is studied. After pretreatment either by formaldehyde solution or by air glow discharge plasma, the PSU fiber membrane was immersed in MAA solution with Ce(IV) and heated under 80°C under N₂ protection. The MAA was induced by the Ce(IV) redox initiation system to polymerize on the PSU fiber membrane surface. It was found that the pretreatment of the membrane is a very necessary condition for the graft copolymerization to obtain high graft degree. For both the formaldehyde and the air glow discharge plasma pretreated membrane, the graft degree increase with the reaction time. To study the reaction mechanism, control experiments were carried out. Membrane surfaces were characterized by ATR‐FTIR and XPS. The reaction mechanism of the graft copolymerization was discussed based on the experimental data. The effect of the graft copolymerization on the membrane's structure and water permeability was finally studied. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3835–3841, 2006     

Oxidative polymerization of N‐vinylcarbazole in polymer matrix

A new class of soluble conductive poly(N‐vinylcarbazole) (PVCz) compounds has been developed by oxidative matrix polymerization of N‐vinylcarbazole (NVCz) by Ce(IV) in the presence of poly(ethylene glycol) (PEG). PEG was found to be a more suitable matrix with which to obtain a stable homogenous ternary complex solution when compared with poly(acrylic acid) (PAA) and poly(vinylpyrrolidone) (PVP). The role of PEG, NVCz and Ce(IV) concentration, order of component addition, the structure of the polymer matrix, molecular weight of polymer and the effect of solvent have been investigated. Obtaining soluble PEG–Ce(III)–PVCz ternary complexes was shown by cyclic voltammetric measurements, and the initial rate of formation NVCz cation radicals as calculated using UV–visible spectrophotometry. Advantageously with these soluble complexes, conductivities could be measured both in solution and in the solid state. © 2001 Society of Chemical Industry     

Fluorescence quenching method for measuring monomer consumption rates during free‐radical crosslinking copolymerization

The steady‐state fluorescence (SSF) technique was used to study the polymerization rate in free‐radical crosslinking copolymerization (FCC) of methyl methacrylate (MMA) and ethylene glycol dimethacrylate (EGDM). Pyrene (Py) was used as a fluorescent probe for the in situ polymerization experiments. The increase in Py intensity was monitored during FCC. The Stern–Volmer kinetic was employed to determine the MMA consumption rate during gelation process for various EGDM contents and at different temperatures. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1907–1913, 2001     

Effect of GMA on monodisperse epoxy‐functionalized polymer microsphere particles by dispersion copolymerization of styrene with glycidyl methacrylate

Monodisperse poly[styrene‐co‐glycidyl methacrylate (GMA)] microparticles were synthesized by dispersion copolymerization in a water–ethanol medium. The effects of various polymerization parameters on the particle size and size distribution of the dispersion copolymerization were investigated. The dispersion of polymer particles decreased when the GMA was added if the polystyrene homopolymer particles were polydispersed. The GMA acted as a comonomer as well as a costabilizer in the dispersion copolymerization of styrene with GMA. The solvency of the monomer increased with the concentration of GMA in the polymerization medium because GMA has a greater hydrophilicity than styrene, resulting in a large particle size and a slow polymerization rate. From an HCl–dioxane analysis of the poly(styrene‐co‐GMA) microparticles, great amounts of epoxy groups were detected after the completion of dispersion copolymerization. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1206–1212, 2001     

Aqueous polymerization of ethyl acrylate initiated by ceric ion‐reducing agent systems in nitric acid medium

Kinetic study of aqueous polymerization of ethyl acrylate (EA) was carried out at 30 °C in dilute nitric acid medium by employing ammonium ceric nitrate (ACN)–methyl cellosolve (MC) and ACN–ethyl cellosolve (EC) as redox initiator systems. The ceric ion consumption was found to be first order with respect to ceric ion concentration with both initiator systems. The formation of complexes between Ce(IV) and reducing agents (RA) was observed. The order with respect to Ce(IV), reducing agents and monomer was evaluated for aqueous polymerization of EA by Ce(IV)–MC and Ce(IV)–EC redox initiator systems. The overall activation energy, E_overall, for aqueous polymerization of EA was evaluated in the temperature region of 27–40 °C with both initiator systems. A kinetic mechanism for aqueous polymerization of EA initiated by redox initiator systems is presented. © 2001 Society of Chemical Industry     

Monomer reactivity ratios for acrylonitrile/ammonium itaconate during aqueous‐deposited copolymerization initiated by ammonium persulfate

Monomer reactivity ratios of acrylonitrile/ammonium itaconate during aqueous‐deposited copolymerization initiated by ammonium persulfate were investigated. Kelen–Tudos method was used to examine the reactivity ratios. It was shown that the reactivity ratios were influenced by the conversions and temperatures of copolymerization. The reactivity ratios in aqueous‐deposited copolymerization system were similar to those in the solution polymerization system at polymerization conversions of less than 5% [reactivity ratio of acrylonitrile (r₁) 0.842 ± 0.02, reactivity ratio of ammonium itaconate (r₂) = 3.624 ± 0.02]. The reactivity ratio of AN rises and that of (NH₄)₂IA decreases, when the polymerization conversion increases till 13%. Aqueous‐deposited copolymerization initiated by AIBN was also studied. It was found that some polymers were formed in water phase and the monomers had different reactivity ratios by comparison with those initiated by ammonium persulfate. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4645–4648, 2006     

Kinetic study of copolymerization of acrylonitrile with ammonium acrylate

Ammonium acrylate was first used to successfully copolymerize with acrylonitrile. Kinetics of copolymerization of acrylonitrile with ammonium acrylate was investigated in a H₂O/dimethylsulfoxide (DMSO) mixture. The rate of copolymerization and particle size were measured. Kinetic equation of the copolymerization was obtained. Effect of copolymerization systems on monomer apparent reactivity ratios for acrylonitrile/ammonium acrylate copolymers was studied in comparison. Values of monomer apparent reactivity ratios were calculated by Kelen‐Tudos method. It has been found that monomer apparent reactivity ratios in water‐rich reaction medium [H₂O/DMSO>80/20] are approximately equivalent to those in aqueous suspension polymerization system. In DMSO‐rich reaction medium (DMSO/H₂O > 80/20), apparent reactivity ratios are similar to those in solution polymerization system. With an increase in polarity of solvent, values of apparent reaction ratios both decrease. The values of apparent reaction ratios gradually tend to 1 with increase in the copolymerization temperature. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4679–4683, 2006     

Preparation and characterization of amphiphilic block copolymer of polyacrylonitrile‐block‐poly(ethylene oxide)

The synthesis of polyacrylonitrile‐block‐poly(ethylene oxide) (PAN‐b‐PEO) diblock copolymers is conducted by sequential initiation and Ce(IV) redox polymerization using amino‐alcohol as the parent compound. In the first step, amino‐alcohol potassium with a protected amine group initiates the polymerization of ethylene oxide (EO) to yield poly(ethylene oxide) (PEO) with an amine end group (PEO‐NH₂), which is used to synthesize a PAN‐b‐PEO diblock copolymer with Ce(IV) that takes place in the redox initiation system. A PAN‐poly(ethylene glycol)‐PAN (PAN‐PEG‐PAN) triblock copolymer is prepared by the same redox system consisting of ceric ions and PEG in an aqueous medium. The structure of the copolymer is characterized in detail by GPC, IR, ¹H‐NMR, DSC, and X‐ray diffraction. The propagation of the PAN chain is dependent on the molecular weight and concentration of the PEO prepolymer. The crystallization of the PAN and PEO block is discussed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1753–1759, 2003     

Cationic copolymerization behavior of a bicyclic orthoester having hydroxy group with glycidyl phenyl ether and volume change on their copolymerization

This article describes cationic ring‐opening copolymerization of a bicyclic orthoester having hydroxy group (BOE‐OH) and glycidyl phenyl ether (GPE), and the volume shrinkage behavior during the copolymerization. THF soluble polyethers [poly(BOE‐OH‐co‐GPE)] were obtained by the copolymerizations at 80–180°C, while crosslinked poly(BOE‐OH‐co‐GPE) was obtained by the copolymerizations at 220–250°C. This crosslinking reaction may originate from the dehydration of methylol groups in the side chain of poly(BOE‐OH‐co‐GPE). The volume shrinkage during the cationic copolymerization reduced as the increase of the BOE‐OH feed ratio. By contrast, the volume shrinkage on the crosslinking polymerization was almost independent on the BOE‐OH feed ratio. Poly(BOE‐OH‐co‐GPE)s with higher BOE‐OH composition showed lower thermal weight loss temperature owing to the release of H₂O by dehydration of methylol groups. The BOE‐OH component in the THF soluble poly(BOE‐OH‐co‐GPE)s lowered the glass transition temperature (T_g), while that in the crosslinked poly(BOE‐OH‐co‐GPE) increased the T_g probably because of the higher crosslinking density. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1356–1361, 2006     

Miniemulsion copolymerization of n‐butyl methacrylate with crosslinking monomers

Miniemulsion copolymerization of n‐butyl methacrylate and crosslinking monomers such as a macromonomer crosslinker (Mac), ethylene glycol dimethacrylate (EGDMA), or an aliphatic urethane acrylate macromonomer (AUA) was utilized to obtain crosslinked latex particles. The crosslinking monomers were added at 0.2 mol %, on the basis of the amount of n‐butyl methacrylate utilized in a polymerization. The development of the gel content during the copolymerization reaction differs depending on the type of the crosslinking monomer. In addition to the crosslinking reactions between the n‐butyl methacrylate and the crosslinking monomers, other kinetic events, such as microphase separation, may have occurred, giving rise to different particle morphologies, dependent on the type of initiator used (i.e., oil‐soluble or water‐soluble). © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1721–1730, 2001     

Lamination of conductive polypyrrole films to poly(tetrafluoroethylene) films via interfacial graft copolymerization

A simple technique for the lamination of a conductive polymer film to an inert dielectric polymer film was demonstrated. The electrochemically synthesized and p‐toluenesulfonic acid‐doped polypyrrole (PPY) film was laminated simultaneously to the argon plasma‐pretreated PTFE film during the thermally induced graft copolymerization of the PTFE surface with a functional monomer. The graft copolymerization was carried out using glycidyl methacrylate (GMA) monomer containing 20% v/v hexamethyldiamine (HMDA) and in the absence of any polymerization initiator. Thermally induced graft copolymerization of the GMA monomer on the PPY surface was minimal. The lap shear and T‐peel adhesion strengths of the laminates were found to be dependent on the GMA graft concentration on the PTFE surface, which, in turn, was affected by the plasma pretreatment time of the film. To increase the GMA graft concentration for the enhancement of adhesion strength, the plasma‐pretreated PTFE surfaces were premodified via UV‐induced graft copolymerization with GMA prior to the simultaneous thermal graft copolymerization and lamination process. The modified surfaces and interfaces were characterized by X‐ray photoelectron spectroscopy (XPS). Through XPS measurements of the delaminated surfaces, it was found that the PPY/PTFE laminates failed predominantly by cohesive failure inside the PTFE substrate. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 716–727, 2001     

Controllable radical copolymerization of styrene and methyl methacrylate using 1,1,2,2‐tetraphenyl‐1,2‐bis(trimethylsilyloxy) ethane as initiator

Copolymerization of styrene (St) and methyl methacrylate (MMA) was carried out using 1,1,2,2‐tetraphenyl‐1,2‐bis (trimethylsilyloxy) ethane (TPSE) as initiator; the copolymerization proceeded via a “living” radical mechanism and the polymer molecular weight (M_w) increased with the conversion and polymerization time. The reactivity ratios for TPSE and azobisisobutyronitrile (AIBN) systems calculated by Finemann–Ross method were r_St = 0.216 ± 0.003, r_MMA= 0.403 ± 0.01 for the former and r_St= 0.52 ± 0.01, r_MMA= 0.46 ± 0.01 for the latter, respectively, and the difference between them and the effect of polymerization conditions on copolymerization are discussed. Thermal analysis proved that the copolymers obtained by TPSE system showed higher sequence regularity than that obtained by the AIBN system, and the sequence regularity increased with the content of styrene in copolymer chain segment. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1474–1482, 2001     

Anionic block copolymerization of cyclotetrasiloxanes initiated by 4,4'‐bis(dimethyllithiioxylsilyl)diphenyl ether

The anionic copolymerization of cyclotetrasiloxanes initiated by 4,4′‐bis(dimethyllithiioxylsilyl)diphenyl ether (BDMOLiPE) was carried out for the preparation of poly(diphenyl‐dimethyl‐diphenyl)siloxane block copolymers (PMP). To reduce redistribution reaction, the lithium‐based dianionic initiator (BDMOLiPE) was first used for the copolymerization of the cyclotetrasiloxane monomers without solvent, with dimethyl formamide (DMF) as a promotor. The cyclotetrasiloxanes used involved octamethylcyclotetrasiloxane (D₄), octaphenylcyclotetrasiloxane (P₄), and tetramethyl‐tetravinylcyclotetrasiloxane (V₄). The copolymers obtained were characterized withproton nuclear magnetic resonance spectroscopy, infrared spectroscopy, intrinsic viscosity([η]) determination, transmission electron microscopy, and wide‐angle X‐ray diffraction analysis. The results illustrate that the products should belong to block copolymers but not be too perfect because the block copolymers were scrambled to a certain extent during the copolymerization process. However, we can approximately express them as PMP and PMVP, according to the different order of the feeding in raw materials. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1203–1210, 2001     

Electroinduced dispersion polymerization of acrylonitrile in the presence of poly(acrylic acid) and catalytic amount of CE(IV)

Electroinduced dispersion polymerization of acrylonitrile initiated by Ce(IV) was performed in an electrolytic cell in the presence of poly(acrylic acid) (PAA). Micron‐size polyacrylonitrile (PAN) particles were stabilized with PAA by electrostatic interaction or by a PAA–Ce(III)–PAN ternary complex formation. A PAA–PAN stable polymer was formed in the cathodic compartment, and the reduced initiator was reoxidized in the anode, thus allowing for the continuation of the process. A possible mechanism of polymerization is suggested. © 2002 John Wiley & Sons, Inc. J Appl Polym Sci 84: 723–728, 2002; DOI 10.1002/app.10076     

Microwave radiation copolymerization of dibutyltin maleate and allyl thiourea

This article reports on an investigation of microwave radiation copolymerization of dibutyltin maleate (DBTM) with allyl thiourea (AT) and the copolymers it produced. The effect of radiation energy, composition of monomer, amount of initiator, and amount and kind of inorganic oxide (Al₂O₃ or SiO₂) as reaction sensitizers on the copolymerization conversion and polymer‐inherent viscosity were systematically studied, and simultaneously compared with the relevant conventional thermopolymerization. The reactivity ratios for DBTM and AT were determined using liquid chromatography. The copolymerization mechanism of microwave radiation was probed using a free‐radical capturing agent (DPPH). The copolymers obtained were used as heat‐stabilization agent of PVC resin. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 312–318, 2001     

Dispersion copolymerization of acrylonitrile‐vinyl acetate in supercritical carbon dioxide

Dispersion copolymerization of acrylonitrile‐vinyl acetate (AN‐VAc) had been successfully performed in supercritical carbon dioxide (ScCO₂) with 2,2‐azobisisobutyronitrile (AIBN) as a initiator and a series of lipophilic/CO₂‐philic diblock copolymers, such as poly(styrene‐r‐acrylonitrile)‐b‐poly(1,1,2,2‐tetrahydroperfluorooctyl methacrylate) (PSAN‐b‐PFOMA), as steric stabilizers. In dispersion copolymerization, poly(acrylonitrile‐r‐vinyl acetate) (PAVAc) was emulsified in ScCO₂ effectively using PSAN‐b‐PFOMA as a stabilizer. Compared with the precipitation polymerization (absence of stabilizer), the products prepared by dispersion polymerization possessed of higher yield and higher molecular weight. In addition, the particle morphology of precipitation polymerization was irregular, but the particle morphology of dispersion polymerization was uniform spherical particles. In this study, the effects of the initial concentrations of monomer and the stabilizer and the initiator, and the reaction pressure on the yield and the molecular weight and the resulting size and particle morphology of the colloidal particles were investigated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5640–5648, 2006     

Nitroxide‐mediated homopolymerization and copolymerization of 2‐vinylpyridine with styrene

Homopolymerization and copolymerization of 2‐vinylpyridine (2VP) with styrene (S) at 125°C in the presence of 2,2,6,6‐tetramethyl piperidin‐1‐yloxyl (TEMPO) radicals have been studied. The homopolymerization was carried out with 2,2′‐azobis(isobutyronitrile) (AIBN) as a thermal initiator or without AIBN in the initial reaction mixture. In the copolymerization initiated with AIBN, the molar fraction of 2VP in the feed, F_2VP, varied in the range of 0.1–0.9; F_2VP = 0.65 was found to be the azeotropic composition. The linear semilogarithmic time–conversion plots demonstrated a pseudoliving nature of the polymerizations under study. The molecular weight–conversion dependences indicated the participation of side reactions, diminishing the number of TEMPO‐terminated polymer chains. The synthesized homopolymers and copolymers were characterized using size‐exclusion chromatography (SEC), nitrogen analysis, and NMR spectroscopy. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2024–2030, 2001     

Electrochemically induced redox polymerization of acrylamide

Polymerization of acrylamide (AA) has been studied in aqueous solution in the presence of a Ce(IV) salt–oxalic acid initiator system in an electrochemical cell with and without separation of anolyte and catholyte. For reactions that required the cathode and anode sections to be analyzed individually, a cell whose compartments were divided by a sintered glass disk of the medium porosity was employed. Polymerization was initiated by a free radical that is formed by the fast reaction of oxalic acid and Ce(IV). The electrolysis of the reaction solution results in regeneration of Ce(IV), which can oxidize oxalic acid to produce radicals. The effect of sulfuric acid and cerium (IV) salt concentration and temperature on the yield of electroinitiated polymerization in different cell designs and structural identification of products were performed. Reaction was also followed by cyclic voltametric measurements, and a mechanism was proposed. Results indicated that the electrolysis method with a divided cell (85% conversion) shows advantages, compared with nonelectrolytic (5% conversion) and with undivided electrochemical cell (25% conversion) methods where a high concentration of initiator was used. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 861–869, 1999