Introduction of peroxide groups onto carbon black surface by radical trapping and radical graft polymerization of vinyl monomers initiated by the surface peroxide groups

The introduction of peroxide groups onto carbon black surface was achieved through the trapping of the peroxide radicals formed by the decomposition of polymeric peroxide, such as poly(tetraethylene glycol peroxyadipate) (ATPPO), and bis-peroxide, such as 1,1′-bis (t-butyldioxy)cyclohexane (Perhexa-C), by the surface: the amount of peroxide groups introduced onto carbon black surface by the treatment with ATPPO and Perhexa-C were determined to be 0.07 mmol/g and 0.12 mmol/g, respectively. The polymerization of vinyl monomers with positive e-value, such as methyl methacrylate and 2-hydroxyethy methacrylate, was successfully initiated by the peroxide groups introduced onto carbon black surface. During the polymerization, the corresponding polymers were effectively grafted onto the surface as a result of the propagation of polymer from the surface radicals formed by decomposition of the peroxide groups. The polymerization of vinyl monomers with negative e-value, such as styrene and vinyl acetate, however, was scarcely initiated by the peroxide groups on carbon black. This may be due to the fact that surface active radicals, which were formed by the hydrogen abstraction from carbon black by fragment radicals, inhibit the polymerization of vinyl monomers with negative e-value. © 1996 John Wiley & Sons, Inc.     

Polymerization of methyl methacrylate by resin containing polyethylenepolyamine side chain–peroxide system

Macroreticular resins (RST) bearing polyethylenepolyamine side chain were prepared by the amination of the chloromethylated macroreticular styrene—divinylbenzene copolymer beads. The polymerization of methyl methacrylate (MMA) was carried out in a water—organic solvent mixture containing hydroperoxide and RST. The polymerization of MMA proceeded smoothly in the presence of both hydroperoxide and RST. The presence of water was indispensable for this polymerization. 1,4-Dioxane hydroperoxide showed a high activity for the polymerization of MMA. The polymerization of MMA by this system was greatly affected by the structure of the resins. It was especially accelerated by using macroreticular resins with appropriate porosities.     

Vinyl Polymerization Initiated by the Methylated Cyclodextrin/Metal Ion System in Water

The polymerization of the vinyl monomers methyl methacrylate (MMA), benzyl methacrylate, and styrene, has been carried out using methylated cyclodextrins, for example, heptakis(2,6,0-dimethyl)-β-cyclodextrin, and heptakis (2,3,6-0-trimethyl)-β-cyclodextrin. These methylated cyclodextrins were found to initiate polymerization of the vinyl monomers in combination with water and a small amount of Cu(II) ion, in analogy with β-cyclo-dextrin (β-CD). Generally, the initiating ability of the methylated cyclodextrins/Cu(II) ion system for the polymerization of MMA was larger than that of the β-CD/Cu(II) ion system. Moreover, the introduction of a phosphate group into a methylated cyclodextrin molecule was found to increase the initiating ability for the polymerization of MMA.     

Preparation of block copolymers by use of peroxide-terminated prepolymer

Block copolymers containing poly(tetramethylene oxide) and poly(methyl methacrylate) segments were prepared. A commercially available poly(tetramethylene oxide) terminated with tolylene diisocyanate was capped with tert-butyl hydroxymethyl peroxide and the resulting prepolymer peroxide was used as a free-radical initiator of vinyl polymerization. Block copolymers formed in temperature-programmed vinyl polymerizations possessed improved impact strengths over poly(methyl methacrylate) from 0.35 to 1.18 for a fixed (nonoptimized) block length of poly(tetramethylene oxide).     

Polymerization of Vinyl Monomers Using Oxidase Catalysts

Polymerization of vinyl monomers using oxidase as catalyst has been performed under argon in the presence of acetylacetone as a mediator and without the use of hydrogen peroxide. The polymerization of acrylamide was catalyzed by a laccase or sarcosine oxidase catalyst in distilled water and efficiently produced the polymer with high molecular weight. In the polymerization using the laccase catalyst, the effects of temperature, time, and amounts of enzyme and mediator have been systematically investigated. On the other hand, various other oxidases such as bilirubin, choline, and xanthine oxidases showed no or little activity for the vinyl polymerization. The laccase/acetylacetone catalyst induced the polymerization of methyl methacrylate and styrene in a mixture of water and tetrahydrofuran. Laccase alone also acted as a catalyst for the vinyl polymerization of acrylamide and methyl methacrylate without acetylacetone. In the polymerization of methyl methacrylate using lipoxidase as the catalyst in the presence of acetylacetone, the reaction occurred in air.     

Heterogeneous initiators for the synthesis of polymer nanocomposites

Nanocomposites are obtained by the radical polymerization of styrene and methyl methacrylate on the surface of a dispersed filler containing chemisorbed compounds of quaternary ammonium, which catalyze decomposition of cumene hydroperoxide. The heterogeneous catalysts of hydroperoxide decomposition are obtained via the adsorption of cetyltrimethyl ammonium bromide and acetylcholine chloride on sodium montmorillonite, cellulose, and chitosan. The highest rate of the polymerization of both monomers is provided by the cellulose–cetyltrimethyl ammonium bromide catalyst. For a more hydrophilic methyl methacrylate, the rate of radical initiation is significantly lower at the same concentrations of the catalyst and hydroperoxide compared with hydrophobic styrene; however, the rate of polymerization is higher than for styrene because of a higher activity of methyl methacrylate in chain-propagation reactions. Relatively high rates of radical generation upon contact of cellulose–cetyltrimethyl ammonium bromide and cellulose–acetylcholine with hydroperoxides open the possibility to create cellulose-based disinfecting and medical materials.     

Polymerization of methyl methacrylate by the binary system of the copper–amine complex type resin and carbon tetrachloride

The polymerization of vinyl monomers initiated by binary initiator systems composed of a copper–amine complex type resin and organic halides has been studied. These binary systems initiated the polymerization of various vinyl monomers. A kinetic study of the polymerization of methyl methacrylate initiated by the copper–amine complex resin–CCl₄ system was carried out, and it was found that the polymerization proceeds by way of a radical mechanism. This fact was also supported by the copolymerization of methyl methacrylate with styrene. The overall activation energy of the polymerization of methyl methacrylate was estimated as 8.4 kcal/mole. The activity of the initiator systems was greatly dependent upon the dissociation energy of carbon–halogen bonds in the organic halides. A possible initiation mechanism with the binary systems is proposed and discussed.     

Neodymium Catalyst for the Polymerization of Dienes and Polar Vinyl Monomers

Ziegler–Natta catalysts have played a major role in industry for the polymerization of dienes and vinyl monomers. However, due to the deactivation of the catalyst, this system fails to polymerize polar vinyl monomers such as vinyl acetate, methyl methacrylate, and methyl acrylate. Herein, a catalytic system composed of NdCl₃⋅3TEP/TIBA is reported, which promotes a quasi‐living polymerization of dienes and is also active for the homopolymerization of polar vinyl monomers. Additionally, this catalytic system generates polymyrcene‐b‐polyisoprene and poly(myrcene)‐b‐poly(methyl methacrylate) diblock copolymers by sequential monomer addition. To encourage the replacement of petroleum‐based polymers by environmentally benign biobased polymers, polymerization of β‐myrcene is demonstrated with a catalytic activity of ≈106 kg polymer mol Nd⁻¹ h⁻¹.     

Effect of amines on vinyl polymerization initiated by chromous acetate–alkyl halide systems

The radical polymerization of vinyl monomers initiated by Cr²⁺–RX in the presence of various amines was studied in DMF at 30°C. Polyamines able to form the chelate complex with Cr²⁺ accelerated the rate of polymerization of styrene in the following order: ethanolamine > triethylenetetramine > diethylenetriamine > ethylenediamine. However, aliphatic monoamine, hexamethylenediamine, and aromatic diamine did not have any effect on the polymerization. These results suggest that the effect of multidentate ligands may be associated with chelating effects which affect the electron transfer ability of the metal complex. An apparent activation energy of 8.2 kcal/mole for the polymerization of styrene was obtained in the presence of ethanolamine. With the Cr²⁺–CHCl₃ system, on addition of ethanolamine, the polymerization of methyl methacrylate was accelerated, and acrylonitrile and vinyl chloride, could be polymerized.     

Catalytic action of metallic salts in autoxidation and polymerization. VIII. Polymerization of methyl methacrylate by various metal acetylacetonate–cyclic ether hydroperoxides

Polymerization of methyl methacrylate by cyclic ether hydroperoxide–metal acetylacetonate systems for a number of different metals was carried out to compare with the tert-butyl hydroperoxide–metal acetylacetonate initiating systems. The rate of polymerization of methyl methacrylate with cyclic ether hydroperoxides as initiating systems was much higher than that with tert-butyl hydroperoxide. In cyclic ether hydroperoxide initiating systems, V(III), Co(II,III), Fe(III), Cu(II), and Mn(II) promoted the polymerization rate markedly, and Zn(II), Ni(II), Al(III), and Mg(II) had little or no effect; in the tert-butyl hydroperoxide initiating system only V(III), Co(II), and Mn(II) enhanced polymerization rate, and most of other metals showed little or no effect. Furthermore, noticeable differences in color of solution and appearance during polymerization, and in relation between conversion and the degree of polymerization were observed. The effect of metal acetylacetonates on hydroperoxide initiators in polymerization of methyl methacrylate was also compared with that on the decomposition of hydroperoxides.     

4,4′-二(硬脂酰胺基)二苯甲烷在乙烯基类单体中的分子组装及其结构形态研究

4,4′-二(硬脂酰胺基)二苯甲烷(BSDM)能在乙烯基类单体中进行聚集、自组装,并可使苯乙烯、丙烯酸丁酯、甲基丙烯酸甲酯、甲基丙烯酸-2-羟基乙酯等凝胶化,形成相应的分子凝胶.凝胶/溶胶相变温度(TGS)与BSDM浓度有关,BSDM质量分数越大,凝胶体系中分子间氢键和π-π键越多,要破坏它们所需要的能量越高,TGS因而也就越高.透射电镜表明,BSDM在各种可聚合溶剂中通过分子间相互作用形成类似纤维状的聚集体结构.BSDM在可聚合溶剂聚合前后的偏光显微照片表明,BSDM在体系中的晶型结构是球晶.     

(Meth)acrylate vinyl ester hybrid polymerizations

In this study, vinyl ester monomers were synthesized by an amine catalyzed Michael addition reaction between a multifunctional thiol and the acrylate double bond of vinyl acrylate. The copolymerization behavior of both methacrylate/vinyl ester and acrylate/vinyl ester systems was studied with near‐infrared spectroscopy. In acrylate/vinyl ester systems, the acrylate groups polymerize faster than the vinyl ester groups resulting in an overall conversion of 80% for acrylate double bonds in the acrylate/vinyl ester system relative to only 50% in the bulk acrylate system. In the methacrylate/vinyl ester systems, the difference in reactivity is even more pronounced resulting in two distinguishable polymerization regimes, one dominated by methacrylate polymerization and a second dominated by vinyl ester polymerization. A faster polymerization rate and higher overall conversion of the methacrylate double bonds is thus achieved relative to polymerization of the pure methacrylate system. The methacrylate conversion in the methacrylate/vinyl ester system is near 100% compared to only ～60% in the pure methacrylate system. Utilizing hydrophilic vinyl ester and hydrophobic methacrylate monomers, polymerization‐induced phase separation is observed. The phase separated domain size is in the order of ～1 μm under the polymerization conditions. The phase separated domains become larger and more distinct with slower polymerization and correspondingly increased time for diffusion. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2509–2517, 2009     

Graft polymerization of vinyl monomers onto cotton fibres pretreated with amines

The influence of treating cotton fibres with several amines on the mechanical properties, moisture sorption ability before and after graft polymerization, and on graft yields for various water-soluble and water-insoluble vinyl monomers were analysed. As compared to water, the treatment with amines, ethylenediamine (EDA) in particular, resulted in a decrease in the crystallinity and tensile strength of the cotton fibres, and an increase in the moisture sorption. The graft yields of amine-treated cotton fibres using water-soluble monomers, acrylic acid (AA), methacrylic acid (MAA) and acrylamide (AM) were greater than those observed for water-treated cotton fibres, whereas the graft yields using water-insoluble monomers, methyl acrylate (MA), methyl methacrylate (MMA) and vinyl acetate (VA) were lower. The moisture sorption ability was improved by the graft polymerization with water-soluble monomers. The improvement was enhanced for MA and MAA by treatment with sodium hydroxide to form the corresponding sodium carboxylate derivatives. The tensile strength of EDA-treated cotton was slightly reduced by grafting, while that of the water-activated cotton yarn was barely changed. These results suggest that the graft polymerization of amine-treated cotton fibres with certain vinyl monomers increased the moisture sorption ability without resulting in increased fibre rigidity.     

η5-cyclopentadienyl-η2-styrenedicarbonylmanganese for initiation of free-radical polymerization of vinyl monomers

The polymerization of styrene, methyl methacrylate, and vinyl chloride catalyzed by η⁵-cyclopentadienyl-η²-styrenedicarbonylmanganese is studied. It is shown that the cyclopentadienyl complex of manganese containing the monomer ligand (styrene) in the coordination sphere can initiate the radical polymerization of vinyl monomers in a mild temperature range. On the basis of the experimental data and the quantum-chemical simulation of the initial stages of the process, schemes describing the initiation of polymerization under the action of the complex under study and the binary initiating system containing carbon tetrachloride are advanced. In the latter case, additional acceleration of the reaction is related to the interaction of carbon tetrachloride with the triplet form of the manganese complex that yields trichloromethyl radicals initiating polymerization.     

In‐Situ Kinetic Pursuit of Emulsion Crosslinking Copolymerizations of Monomethacrylate and Dimethacrylate by Means of ReactIR®

The usefulness of the ReactIR® reaction analysis system as a powerful tool to in‐situ monitor the kinetics of the emulsion polymerization of vinyl monomers was verified by comparison with the conventional gravimetric method and by checking the rate dependencies on initiator and surfactant concentrations in the emulsion polymerization of butyl methacrylate (BMA). The system was then applied to the kinetic monitoring of emulsion crosslinking copolymerizations of monomethacrylate and dimethacrylate, including methyl methacrylate/ethylene dimethacrylate and BMA/1,6‐hexanediol dimethacrylate systems of different hydrophilicities.     

A novel fluorine‐containing graft copolymer bearing perfluorocyclobutyl aryl ether‐based backbone and poly(methyl methacrylate) side chains

A series of novel graft copolymers consisting of perfluorocyclobutyl aryl ether‐based backbone and poly(methyl methacrylate) side chains were synthesized by the combination of thermal [2π + 2π] step‐growth cycloaddition polymerization of aryl bistrifluorovinyl ether monomer and atom transfer radical polymerization (ATRP) of methyl methacrylate. A new aryl bistrifluorovinyl ether monomer, 2‐methyl‐1,4‐bistrifluorovinyloxybenzene, was first synthesized in two steps from commercially available reagents, and this monomer was homopolymerized in diphenyl ether to provide the corresponding perfluorocyclobutyl aryl ether‐based homopolymer with methoxyl end groups. The fluoropolymer was then converted to ATRP macroinitiator by the monobromination of the pendant methyls with N‐bromosuccinimide and benzoyl peroxide. The grafting‐from strategy was finally used to obtain the novel poly(2‐methyl‐1,4‐bistrifluorovinyloxybenzene)‐g‐poly(methyl methacrylate) graft copolymers with relatively narrow molecular weight distributions (M_w/M_n ≤ 1.46) via ATRP of methyl methacrylate at 50 °C in anisole initiated by the Br‐containing macroinitiator using CuBr/dHbpy as catalytic system. These fluorine‐containing graft copolymers can dissolve in most organic solvents. This is the first example of the graft copolymer possessing perfluorocyclobutyl aryl ether‐based backbone. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Polymerizability of unsaturated monomers capable of forming stable radicals

Some unsaturated monomers bearing hindered phenol and arylamine groups capable of forming stable radicals were prepared. Radical polymerizations of vinyl monomers having such groups were investigated with the use of azobisisobutyronitrile, benzoyl peroxide, cumene hydroperoxide, and tetraethylthiuram disulfide as initiator. Polymerizations of these monomers went normally only when azobisisobutyronitrile was used as initiator. The other initiators inhibited polymerizations remarkably or completely. The results suggest that radicals resulting from benzoyl peroxide and cumene hydroperoxide or tetraethylthiuram disulfide abstract hydrogen of the phenol or the amine to produce the stable radicals, thereby inhibiting the polymerization. Meanwhile, carbon radicals resulting from azobisisobutyronitrile add selectively to the vinyl double bonds of the monomers to initiate the polymerizations. The vinyl derivatives as well as allyl derivatives and cinnamic acid derivatives copolymerize easily with conventional monomers such as styrene, maleic anhydride, and butadiene, again, only when azobisisobutyronitrile was used as initiator. Antioxidative properties for styrene copolymers and butadiene-styrene copolymers incorporating the hindered phenol monomers were investigated.     

Grafting of polyethylene powder by vinyl monomers in heterogeneous systems

Polyethylene powder bearing hydroperoxide groups was used for grafting of different monomers in aqueous and nonaqueous media. Polymerization of methyl methacrylate in the matrix of photooxidized polyethylene proved to be a sensitive method for detection of early stages of photodegradation. A new redox-initiation system was developed for grafting of vinyl chloride onto hydroperoxidized polyethylene powder.     

Radical graft polymerization of vinyl monomers onto nanoparticles in ionic liquid initiated by azo groups introduced onto the surface

The radical graft polymerization of vinyl monomers, such as styrene and methyl methacrylate, initiated by azo groups introduced onto silica nanoparticle and carbon black surfaces in room temperature ionic liquid (IL) were investigated. In this work, 1‐butyl‐3‐methylimidazolium hexafluorophosphate ([C₄mim][PF₆]) was used as IL. The percentage of polystyrene and poly(methyl methacrylate) grafting onto silica nanoparticle and carbon black increased with increasing reaction time. The percentage of grafting in IL was much larger than that in 1,4‐dioxane. The molecular weight of polystyrene grafted onto the silica surface in IL was almost equal to that in 1,4‐dioxane. The result indicates that the amount of grafted polystyrene in IL is five times that in 1,4‐dioxane. This may be due to the fact that lifetime of the surface radical formed by the group of azo is prolonged because of high viscosity of IL. Therefore, the surface azo groups were effectively used as initiating sites for the graft polymerization. In addition, the reduction of waste solvent was achieved by use of IL as reaction solvent, because unreacted monomer could be removed under vacuum after the reaction and the reuse of IL was easily achieved. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1143–1149, 2007     

Photoinitiating capabilities of vinyl polyperoxides and metamorphosis of block-into-block copolymer

This article describes the first comprehensive study on the use of a vinyl polyperoxide, namely poly(styrene peroxide) (PSP), an equimolar alternating copolymer of oxygen and styrene, as a photoinitiator for free radical polymerization of vinyl monomers like styrene. The molecular weight, yield, structure and thermal stability of polystyrene (PS) thus obtained are compared with PS made using a simple peroxide like di-t-butyl peroxide. Interestingly, the PS prepared using PSP contained PSP segments attached to its backbone preferably at the chain ends. This PSP–PS–PSP was further used as a thermal macroinitiator for the preparation of another block copolymer PS-b-PMMA by reacting PSP–PS–PSP with methyl methacrylate (MMA). The mechanism of block copolymerization has been discussed. © 1996 John Wiley & Sons, Inc.