Controlled radical (co)polymerization of (meth)acrylic esters via the reversible addition-fragmentation chain-transfer mechanism

The homopolymerization of acrylic and fluoroacrylic esters mediated by benzyl dithiobenzoate and dibenzyl trithiocarbonate proceeds in the controlled mode via the reversible addition-fragmentation chain-transfer mechanism, while the controlled radical polymerization of methacrylic esters is not effected under these conditions. The molecular-mass characteristics of the copolymers of acrylic and methacrylic esters may be satisfactorily controlled by benzyl dithiobenzoate-mediated copolymerization when the content of acrylic esters is no less than 50 mol %. If a reversible addition-fragmentation chain-transfer agent active with respect to only one of the monomers is used, compositionally homogeneous narrowly dispersed copolymers are formed via the azeotropic copolymerization of the monomers up to high conversions. The controlled copolymerization of N-vinylpyrrolidone and fluoroacrylates allows the synthesis of alternating narrowly dispersed amphiphilic copolymers with properties different from those of alternating copolymers with a broad molecular-mass distribution.     

Hydrophile Polymergele mit reaktiven Gruppen, 1. Mitt.: Herstellung und Polymerisation von Glucose- und Saccharosemethacrylaten

The synthesis of new hydrophilic polymer carriers on the basis of glucose-and sucrosemethacrylates is described. The monomer mixtures were prepared by reaction of glucose or sucrose with methacrylic anhydride or methacry-loylchloride in pyridine and by transesterification of sucrose with methylmethacrylate. Mixtures of methacrylic esters of glucosides could be obtained by analogous reaction of glucosides with methylmethacrylate. Radical polymerisation of the resulting mixtures of mono-and polyfunctional methacrylic esters of glucose and sucrose yielded crosslinked hydrophilic gels, swellable in water and polar organic solvents. The degree of crosslinking is determined by the ratio of mono- to polyfunctional esters in the monomer mixture, which depends on the molar ratio of reactants in the starting mixture. These neutral reactive carriers are stable to changes inpH and to biological degradation.

     

Polymerization of asymmetric polyfunctional monomers. III. Ionic polymerization of acrylic and methacrylic esters of 2-allylphenol

The polymerization of acrylic and methacrylic esters of 2-allyphenol with different anionic, cationic and coordination catalysts was studied. The polymerization occurs exclusively or predominantly through (meth)acrylic C?C double bonds in all the studied cases. With anionic catalysts the allylic groups are not polymerizable and the polymers have linear structure. Polymerization with catalysts based on dialkylaluminum chloride (alone or associated with some metal salts) yields soluble or partially crosslinked polymers, depending on the reaction conditions. The crosslinking is due to the participation of allylic groups in the polymerization reactions. Copolymers of acrylic and methacrylic esters of 2-allylphenol with styrene, acrylonitrile, methyl methacrylate, N-vinylcarbazole and 1,3-pentadiene were synthesized by copolymerization in the presence of anionic catalysts and of systems based on dialkylaluminum chloride.     

Synthesis and thermal self-crosslinking reaction of polymer containing spiro ortho ester and carboxylic acid

Polymers with both pendant spiro ortho ester and carboxylic acid moieties were synthesized by partial esterification of poly(methacrylic acid), poly(methacrylic acid-co-methyl methacrylate), or poly(methacrylic acid-co-styrene) with halomethylated spiro ortho esters in the presence of 1,8-diazabicyclo[5,4,0]undecene-7 in dimethyl sulfoxide. The extent of esterification increased with increasing reaction temperature. The reaction of polymeric carboxylic acids with chloromethylated spiro ortho esters proceeded to 80% of conversion at 100°C for 120 h. In contrast, the degree of esterification with bromomethylated spiro ortho ester reached 80% at 60°C within 24 h. Thermo-crosslinking of polymers having pendant spiro ortho ester moiety and carboxylic acid could be effected in films. The rate of spiro ortho ester ring-opening increased with increasing reaction temperature and with increasing content of carboxylic acid groups in the polymer. Further, the rates of gel production were also measured. The polymer containing an equimolar mixture of spiro ortho ester moieties and carboxylic acids exhibited the highest reactivity. In addition, it was found that thermal crosslinking reaction of the polymer occurred with minimum volume shrinkage.     

A versatile kit of additives to lubricating oils

Various mixtures of imidazolines, copolymers of methacrylic acid esters, and trithiolanes were examined as additives to motor oils for diesel fuels or to cutting fluids.     

Two Selective Practical Routes to ω-Cyanoalkyl Methacrylic Esters

Convenient and selective preparations of ω-cyano-alkyl methacrylic esters are described using either PTC conditions or acetone cyanohydrin. The scope and limitations of the two methods are compared.     

Method for synthesis of 1-adamantyl esters of unsaturated acids

New method for synthesis of adamantyl esters of acrylic, methacrylic, and cinnamic acids was developed. The reactions carried out under mild conditions in the absence of catalysts provide a high yield.     

Study of the Isothermal Bulk Polymerization of Methacrylic Acid and Some Methacrylic Acid Esters by Differential Scanning Calorimetry

Abstract

The course of the isothermal bulk polymerization of methacrylic acid and some methacrylic acid esters differing in the length of the ester group was studied by differential scanning calorimetry at different temperatures. The enthalpies of polymerization, the residual monomer content, the overall reaction rate constants, and the overall activation energies were calculated. The molecular weight averages of the synthesized polymers before and after the gel effect were measured by gel permeation chromatography.     

Structure and Properties of Zinc-containing Copolymers Based on (Meth)Acrylate Monomers

The kinetic parameters of radical emulsion copolymerization of zinc-containing copolymers with esters of acrylic and methacrylic acids were studied. The effective relative activities of the monomers were calculated from experimental data and the properties of the metal-containing copolymers were assessed as influenced by the structure of the organic monomers.     

Synthesis and characterization of some oligothioacrylate esters and their polymers—II

Condensation telomerization is used for the synthesis of a new class of oligothioacrylate esters by means of the interaction of various dicarboxylic acids with thiodiglycol and methacrylic acid. During the condensation telomerization, the thiodiglycol undergoes homopoly condensation, the mechanism of which is suggested. The length of the polythiodiglycol unit entering the oligothioester chain depends on the activity of the dicarboxylic acid.     

大口径毛细管气相色谱法在甲基丙烯酸特种酯合成中的应用

 用大口径毛细管气相色谱法对甲基丙烯酸特种酯合成反应液中的各组分进行了分离分析鉴定。色谱柱 :高惰性交联SE 5 4大口径石英弹性毛细管柱 ,5 0m× 0 5 3mmi d × 0 6 μm。主组分回收率为 99 71%～ 10 2 89%,相对标准偏差小于 0 1%,可作为甲基丙烯酸特种酯类生产控制的一种实用方法。     

Prodendronic polyamines from stable or labile methacrylates obtained by selective Michael addition onto asymmetric diacrylic compounds

A new synthetic strategy for the preparation of methacrylic monomers and polymers carrying acyl β‐amino groups is presented. The approach is based on the Michael addition of aliphatic amines onto asymmetric acrylic/methacrylic compounds, reacting the amine highly selectively with the acrylic unit while leaving the methacrylic moiety unreacted. The corresponding polymers are then obtained by conventional radical polymerization. The use of N,N,N′,N′‐tetraethyldiethylenetriamine (TEDETA) as the secondary amine leads to TEDETA moieties supported on polymeric chains. The new aminopolymers are sensitive to pH and to temperature exhibiting a lower critical solution temperature of between 50 and 90 °C. A further interesting feature of the new approach is that the stability toward hydrolysis of the side β‐amino acyl compounds was found to be dependent on whether an acrylamide or an acrylate is employed as the acrylic group of the asymmetric starting material. The esters exhibit an enhanced sensitivity to hydrolysis, compared to standard aliphatic esters, and decompose releasing a derivative of the amine precursor, within hours or weeks, depending on the pH and temperature conditions. The use of the amides leads to stable polymers when the same experimental conditions are applied. The novel dendronic polyamines have been proven to interact with DNA and to transfect cells with efficiency close to that obtained with polyethyleneimine vectors used as positive controls. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 2297–2305     

Polyfluoroalkyl Chlorosulfites as New Polyfluorinating Agents

The interaction of polyfluorinated alcohols with triethylamine and the kinetics of the reaction of the resulting triethylamine complexes with thionyl chloride were studied, the mechanism of formation of polyfluoroalkyl chlorosulfites was considered, and the optimal reaction conditions were found. The alkylating power of polyfluoroalkyl chlorosulfites was studied in reactions with alkali metal halides (to obtain polyfluorohaloalkanes), in synthesis of acrylic and methacrylic acid esters, and in synthesis of polyfluoroalkyl ethers (with polyfluoroalkyl 1-adamantyl ethers as example).     

Intramolecular liquid-crystal order in polymers with chain side groups

Hydrodynamic, optical and electro-optical properties of solutions of polyphenyl methacrylic esters of cetyl and nonyl oxybenzoic acids and of random copolymers of the C₁₆ ester with cetyl methacrylate have been investigated.Experimental data show that the molecules of these polymers exhibit intramolecular orientationalpolar order of a mesomorphic type in which the side-chains form a mobile liquid-crystalline structure. The intramolecular mesomorphic state is due to the side chain radical containing groups capable of forming thermotropic nematic liquid crystals.     

The multidipole effect in reactions of polyfunctional peroxy radicals

Conclusions The rate constant of the reaction of peroxide radicals of acrylic and methacrylic esters of polyols with nonpolar cumene is not dependent on the number of ester groups, and with polar 2,4,6-tri-tert-butylphenol decreases with an increase in the number of ester groups in the peroxide radical. Both findings are in agreement with the model of a dipole-dipole interaction in reactions of polyfunctional compounds.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 778–781, April, 1985.     

Phasentransferkatalysatoren auf Basis von Saccharose-Ethylenoxid-Addukten

Sucrose ethyleneoxide adducts have been prepared by reaction of sucrose with various amounts of ethyleneoxide inDMSO. The resulting polypode molecules were found to be efficient phase transfer catalysts in nucleophilic substitutions, oxidation and dichlorcarbene generation. Polymerisable polypodes have been obtained by reaction of sucrose ethyleneoxide adducts with methacrylic anhydride or methacryloylchloride in pyridine. Free radical polymerisation of the resulting mixtures of mono- and polyfunctional methacrylic esters of sucrose ethyleneoxide adducts yielded crosslinked gels. These polymer-supported octopus-molecules were found to be efficient triphase catalysts.

     

Enzymes in polymer chemistry, 9. Polymerizable oligoesters from cholic acid via lipase catalyzed condensation reactions

Regioselective oligocondensation of cholic acid in the 3-position was achieved in organic solution in the presence of a lipase from Candida antarctica. Furthermore, a mixture of cholic acid, 11-methacryloylaminoundecanoic acid and the lipase resulted in the production of a radically polymerizable oligo(cholic acid ester) bearing exactly one methacrylic end group. This new monomer was polymerized radically yielding the corresponding comb-polymers bearing several cholic acid esters at the end of the side chains.     

聚丙烯酸增稠剂的反相乳液聚合及其增稠性能

采用具有增稠和抗电解质作用的丙烯酸聚氧乙烯酯活性单体和具有聚合稳定作用的高分子表面活性剂,通过反相乳液聚合法合成了涂料印花用丙烯酸系增稠剂.研究了活性单体、交联剂、反应时间等因素对产物性能的影响.得出活性单体用量占共聚单体摩尔数的0.5%,交联剂占共聚单体质量的0.3%,反应时间为1.5h时,增稠剂的综合效果最好.     

Polymerization photoinitiated by carbonyl compounds. VI. Mechanism of benzil photoinitiation

The mechanism of the photoinitiation of the vinyl polymerization sensitized by benzil and 4,4′-dimethoxybenzil was studied. The monomers considered were methacrylic acid esters and styrene derivatives. All these monomers are efficient quenchers of the excited triplet benzil. However, the initiation efficiency of the benzil is important only when styrene derivatives are employed as monomers. The main polymerization process follows a simple free radical mechanism. The initiation step is a consequence of the interaction (triplet benzil–monomer double bond) through a charge transfer complex.     

Nitroxide‐Mediated Polymerization of Methacrylic Esters: Insights and Solutions to a Long‐Standing Problem

Nitroxide‐mediated polymerization (NMP) is one of the most powerful reversible deactivation radical polymerization techniques and has incredibly gained in maturity and robustness over the last decades. However, control of methacrylic esters is one of the different aspects of NMP that still requires improvement. This family of monomers always represented an important challenge for NMP, despite the many different nitroxide structures that have been designed over the course of time. This Review aims to present the most successful strategies directed toward the control of the NMP technique of methacrylic esters and especially methyl methacrylate. NMP‐derived materials comprising uncontrolled methacrylate segments will also be discussed.