Showing papers on "Methyl acrylate published in 1995"

Living Polymerizations and Copolymerizations of Alkyl Acrylates by the Unique Catalysis of Rare Earth Metal Complexes

Abstract: Rare earth metal complexes such as SmMe(C 5 Me 5 ) 2 (THF) or YMe(C 5 Me 5 ) 2 (THF) (THF = tetrahydrofuran) catalyze the living polymerization of alkyl acrylates (alkyl = methyl (Me), ethyl (Et), n-butyl (nBu), tert-butyl (tBu)) to give high molecular weight polymers, with extremely narrow molecular weight distributions, in high conversion. Random living copolymerization of methyl acrylate with n-butyl acrylate was successful by the effective catalytic action of SmMe(C 5 Me 5 ) 2 (THF). By taking advantage of the living polymerization of alkyl acrylates and alkyl methacrylates, a triblock copolymer of methyl methacrylate/n-butyl acrylate/methyl methacrylate was prepared, and the resulting polymer exhibited good elastic properties. In particular, an 8 :72 :20 copolymer had an ultimate elongation of 163% and compression set of 58%. Block copolymerizations of alkyl acrylates with lactones gave lactone rich copolymers with narrow molecular weight distributions.

Polymers useful as pH responsive thickeners and monomers therefor

Abstract: Novel aqueous thickener or thixotropic polymers are prepared by the copolymerization of (A) about 15-60 weight percent of a C 3 -C 8 alpha, beta-ethylenically unsaturated carboxylic acid monomer, preferably acrylic or methacrylic acid or a mixture thereof with itaconic or fumaric acid, (B) about 15-80 weight percent of a nonionic copolymerizable C 2 -C 12 alpha, beta-ethylenically unsaturated monomer, preferably a monovinyl ester such as ethyl acrylate or a mixture thereof with styrene, acrylonitrile, vinyl chloride or vinyl acetate, and (C) about 1-30 weight percent of a new and novel nonionic ethylenically unsaturated nonionic biphillic monomer such as tristyrylpoly(ethyleneoxy) x methyl acrylate, to provide a stable aqueous colloidal dispersion at an acid pH lower than about 5.0 but becoming an effective thickener for aqueous systems upon adjustment to a pH of about 5.5-10.5 or higher. These polymers adjusted to a pH of about 5.5 or higher are effective thickeners for a wide variety of aqueous systems including cosmetic products, drilling muds, aqueous coating compositions such as latex paint, and high solids compositions such as spackle, grouts, cements, and the like.

Thermoplastic material for drug coatings which dissolve in intestinal juices

Abstract: Thermoplastic materials which comprise a copolymer of (A) 16 to 40 wt % of acrylic and/or methacrylic acid; (B) 30 to 80 wt % of methyl acrylate; and (C) 0 to 40 wt % of another alkyl ester of acrylic and/or methacrylic acid and perhaps conventional auxiliaries for drug coatings are suitable for the production of drug coatings which are soluble in intestinal juices, such as tablet coatings, dies, films, capsules, or multipart dosage units.

Palladium-Catalyzed Cleavage of P-C Bonds in Quaternary Phosphonium Salts and Its Applications to Organic Synthesis

Abstract: Phosphonium salts, PPh4I and PMePh3I, oxdatively add to Pd(methyl acrylate)(PMePh2)2 to give trans-[PdPhI(PMePh2)2] in moderate yields with cleavage of the P-phenyl bond. Conversely thermolysis of trans-PdPhIL2 (L = PMePh2 and PPh3) reductively eliminates PMePh3I and PPh4I, respectively. Application of the P-C bond cleavage process in phosphonium salts to olefination, carbonylation and hydrogenation reactions has been explored.

On the modification of chitosan through grafting

Abstract: The feasibility of grafting poly(methyl acrylate) and poly[1-(methoxycarbonyl) ethylene] onto chitosan, poly-β(1←-4)-2-amino-2-deoxy-d-glucose, was investigated. The grafting reaction was carried out in aqueous solution by using ferrous ammonium sulfate (FAS) in combination with H2O2 as redox initiator. The effects of such reaction variables as chitosan, monomer and initiator concentrations, reaction time, and reaction temperature were determined. Through this study the grafting reaction could be optimized. The grafting yield reached its maximum value of 332% when 0.3 g chitosan was copolymerized with 3 mL monomer at 70°C for 120 minutes with [FAS] = 6 × 10−5 M, [H2O2] = 6 × 10−3 M, and 8 mL water. The grafted chitosan was found to be insoluble in solvents for chitosan and solvents for poly(methyl acrylate), but did show swelling in dilute acetic acid, methanol, acetone, and in an ethanol/2% acetic acid 1:1 mixture. The thermal stability of chitosan and grafted chitosan were studied by dynamic th...

Thermoplastic resin composition

Abstract: PURPOSE:To obtain the composition comprising vinyl chloride resin and a specific acrylic linear polymer, and excellent in delustering property and appearance. CONSTITUTION:This composition comprises (A) 100 pts.wt. of vinyl chloride resin and (B) 1-40 pts.wt. of a hydroxyl group-containing linear polymer comprising (i) 1-80wt.%, preferably 20-50wt.%, of a (meth)acrylic acid hydroxy 1-8C alkyl ester (preferably 2hydroxyethyl methacrylate), (ii) 10-99wt.%, preferably 30-85wt.%, of a methacrylic acid 1-13C alkyl ester (preferably methyl methacrylate), (iii) 0-79wt.%, preferably 0.5-40wt.%, of an acrylic acid 1-8C alkyl ester (e.g. methyl acrylate), and (iv) 0-50wt.% of another copolymerizable vinylic monomer (e.g. styrene, fumaric acid).

Heterogeneous palladium catalysts for the Heck reaction

Abstract: The vinylation of iodobenzene with methyl acrylate was studied using palladium-based heterogeneous catalysts. Methyl cinnamate was formed as vinylation product and benzene as side product. All catalysts were of the type SiO2X-(NH)2-Pd-L2, where L = P(C6H5)3 or C6H5CN and X = Sn, Al or Ti. The catalysts were stable and could be reused several times in normal atmosphere without suffering appreciable loss in catalytic activity. The activity of the catalysts was good even at low temperature, and selectivities were very high. Strong interaction indicating the existence of chemical bonding was found between the modified silica support and palladium complex. A model of the active surface compound is proposed and confirmed.

Preparation of Propylene Carbonate Acrylate and Poly(propylene carbonate acrylate) Electrolyte Elastomer Gels. 13C NMR Evidence for Li+-Cyclic Carbonate Interaction

Abstract: The phosgene-free synthesis of fast curing (2-oxo-1,3-dioxolan-4-yl)methyl acrylate (propylene carbonate acrylate, PCA) is presented. Polymerization of PCA in the presence of plasticizing propylene carbonate (PC) results in the formation of reversibly swellable elastomeric gels. The ionic conductivity of poly(PCA) plasticized with 50 wt % PCA and containing 1 M lithium triflate is 1.7×10 -5 S/cm. Evidence for Li + -cyclic carbonate interaction was found in 13 C CP-MAS NMR spectroscopic analysis of the model compound poly(vinylene carbonate) containing 1 M lithium triflate

Synthesis and Properties of Cationic Organopalladium Complexes. Remarkable Rate Enhancement in Olefin Insertion into the Palladium–Aryl Bond by the Generation of a Cationic Palladium Complex from trans-[PdBr(Ph)(PMe3)2]

Abstract: By removing the bromide ligand in trans-[PdBr(Ph)(PMe3)2] (1) by AgBF4 in the presence and absence of pyridine, pyridine-coordinated and solvent-coordinated cationic complexes, trans-[PdPh(py)(PMe3)2]BF4 (2) and trans-[PdPh(solvent)(PMe3)2]BF4 (3), have been obtained. These cationic phenylpalladium complexes show much greater reactivities than do the parent neutral complex 1 toward olefins to give phenylated olefins by insertion followed by β-hydrogen elimination processes. Kinetic studies concerning the insertion of methyl acrylate into the phenyl-palladium bond have indicated that the reactions are first order in the phenylpalladium complexes and that addition of pyridine to a system containing 2 and methyl acrylate inhibits the insertion reaction of the olefin. The results suggest that the generation of a cationic arylpalladium complex with a vacant site is important for the olefins to be inserted.

Chemical reactions between immiscible polymers in the melt: Transesterification of poly(ethylene‐co‐methyl acrylate) with mono‐hydroxylated polystyrenes

Abstract: This article presents a unique example dealing with how chemical reactions between immiscible polymers in the melt behave differently than they would do in solution. Specifically, a model reaction was chosen: the transesterification between poly(ethylene-co-methyl acrylate) (EMA) and polystyrene mono-hydroxylated at the chain end (PSOH). It was carried out in the melt in a batch mixer. The overall rate of this reaction has a similar dependence of temperature, composition of reactants, and the nature and concentration of catalyst as in solution. The reactivity of PSOH decreases drastically with increasing molecular weight, and it becomes very weak when the molecular weight exceeds 8000 g/mol. As opposed to a reaction in solution or in a homogeneous melt, mechanical mixing increases the reaction rate since it generates interfacial area and reduces the diffusion length. The EMA-g-PS graft copolymer formed at the interfaces reduces the interfacial tension, and increases the miscibility of the reaction mixture. However, its occupation of the interfaces reduces contact between the reactive moieties, thus decreasing the overall reactivity. More importantly and much to our surprise, adding 1 to 2 wt % of an inert solvent increased greatly the overall reaction rate. While an increased interfacial mixing and diffusion by the presence of minor amounts of solvent are thought to be the major factors contributing to the drastic increase in reactivity, numerous questions still remain. Nevertheless, this study clearly showed that as opposed to a reaction in solution, mechanical mixing and the presence of minor amounts of solvent are two additional and critical means to control chemical reactions between immiscible polymer melts. © 1995 John Wiley & Sons, Inc.

Solvent effects on diels-alder reactions: a semi-empirical study

Abstract: Semi-empirical calculations (AMI and PM3) have been used in the framework of the Self-Consistent Reaction Field (SCRF) and supermolecule models in order to analyse solvent effects on the Diels-Alder reactions of cyclopentadiene and 2-methyl-l,3-butadiene (isoprene) with acrylonitrile, acrolein, methyl vinyl ketone, and methyl acrylate. Both SCRF and supermolecule models describe correctly the effect of the solvent on endo/exo selectivities. Supermolecule calculations are suitable to explain the influence of hydrogen bonding on activation barriers, but fail to explain the effect of strong HBD solvents on para/meta regioselectivity.

Laser-induced polymeric film formation from gaseous methyl acrylate

Abstract: Upon exposure to N2 laser light, gaseous methyl acrylate at a pressure of 10–65 Torr produced a solid polymeric material as a thin film on the surface of an optical quartz window. The product yield measured by weighing was proportional to the irradiation time of laser light, and was roughly proportional to the second power of the laser intensity. From the fact that the IR spectrum of the deposited film has bands characteristic of poly(methyl acrylate), it is suggested that two-photon excitation of methyl acrylate under N2 laser light irradiation initiates polymerization of gaseous methyl acrylate. The mechanism resulting in the formation of the polymer film from gaseous methyl acrylate is briefly discussed.

Methyl acrylate: a new sensitizer in nail lacquer

Abstract: Nail lacquer contains 5 or 6 main components (l, 2): the thermoplastic resin toluenesulfonamide-formaldehyde resin (TS-F-R), which improves adhesion of the lacquer to the nail plate and provides hardness and flow of the lacquer, is the best-known allergen in nail cosmetics, and may induce unsuspected clinical symptoms, causing allergic reactions even when hardened (3-5). Because TSF-R is now widely recognized as a potent allergen, it might be expected that substitutes for it would appear on the market.

On the Baylis–Hillman reaction of acrylate, acrylonitrile, and acrolein with some non-enolizable α-dicarbonyl compounds: synthesis of phytotoxic bipolaroxin models

Abstract: The Baylis–Hillman reaction of acrylonitrile, methyl acrylate, and acrolein with several cyclic α-dicarbonyl compounds was investigated. Whereas acrylonitrile reacted with most of these ketones, giving good yields of the expected 1′-cyanovinyl carbinols, the more sterically demanding methyl acrylate failed to undergo the reaction. Attempted Baylis–Hillman reaction of acrolein with the 1,2-dicarbonyl substrates usually resulted in polymers but, in two cases, the desired α-substituted acroleins were obtained. An alternative route to such compounds was developed, employing a Grignard – allylic oxidation sequence. In bioassays, some of the products, embodying the functionality believed responsible for the phytotoxicity of the sesquiterpene bipolaroxin, inhibited germination of lettuce seeds. This activity diminished with time. Keywords: Baylis–Hillman, acrylonitrile, acrylate, acrolein, α-dicarbonyl, bipolaroxin, phytotoxicity.

“Compatibilizing effect” in interpenetrating polymer networks

Abstract: α,ω-Acrylate terminated poly(1,3-dioxolane) (polyDXL) was copolymerized with methyl acrylate and methyl methacrylate for the synthesis of block copolymer networks. It was shown by dynamic mechanical thermal analysis (DMTA) that the presence of covalent bonds between poly DXL and the polyacrylate leads to a high degree of compatibility. In contrast, the combination of the same two components in network form, leading to sequential interpenetrating polymer networks (IPN's), resulted in phase-separated materials. When the above-mentioned block copolymer structures, in which one of the blocks is chemically identical to the polyacrylate used in the second network, were applied in the first network of the IPN, an increase of miscibility between the two types of polymers was observed. DMTA analysis revealed that the morphology of these IPN's could be varied from phase-separated to homogeneous materials by increasing the polyacrylate fraction in the first block copolymer network. The possibility to degrade the poly DXL segments in an acid environment allows the complete degradation and extraction of one network in the IPN's and hence provided an interesting approach to the study of domain characteristics by optical microscopy.

Polyacetal compositions for use in wear applications

Abstract: A polyacetal composition is provided for use in plastic-plastic wear applications, said composition containing about 85 to 99 weight percent polyacetal, about 0 to 5 weight percent polytetrafluoroethylene fibers, about 0.5 to 5 weight percent ethylene methyl acrylate copolymer, and about 0.5 to 5 weight percent of at least one lubricant. The compositions are particularly useful in forming shaped articles for use especially in conveyor chain applications and gear applications.

Water sorption and diffusion in starch/polyolefin blends

Abstract: The kinetics of water sorption by starch filled polyolefins has been investigated using blends of a commercial starch masterbatch with low density polyethylene (LDPE), high density PE (HDPE), and copolymers of ethylene with methyl acrylate (EMA), ethyl acrylate (EEA), and n-butyl acrylate (EBA). Transient state diffusion coefficients (D) of water in the blends were determined using Fickian analysis of the initial stages of the sorption isotherms. Measured D values were several orders of magnitude lower than values reported for either pure starch or LDPE by various investigators. Resin effects on D were in the order D HDPE < D LDPE < D EBA < D EEA < D EMA . The resin effects diminished as the starch content increased. The lower magnitude of D in the blends relative to pure LDPE was attributed to the sorption of water by the dry starch particles, in a manner similar to dual-mode sorption in glassy polymers. Copolymer effects were consistent with reduction in crystallinity caused by the comonomers. The dependence of the diffusion coefficient on starch content was not described by mixing models of heterogeneous systems or percolation theory.

Pulsed laser terpolymerization of styrene, methyl methacrylate and methyl acrylate

Abstract: The propagation rate coefficient of the terpolymerization of styrene, methyl methacrylate and methyl acrylate in bulk was successfully determined at three different monomer compositions. The temperature was varied between 18 and 80°C. The resulting data at 50°C were not in agreement with predictions according to the terminal model with binary reactivity ratios that have been determined by fitting copolymer composition data with the terminal model. This indicates that here also the penultimate unit affects the kinetics.

Assignment of finely resolved 13C NMR spectra of polyacrylates

Abstract: 13 C NMR spectra of poly(methyl acrylate) (PMA), poly(ethyl acrylate) (PEA), poly(isopropyl acrylate) (PIPA), poly(butyl acrylate) (PBA), and poly(isobutyl acrylate) (PIBA) with various tacticities were determined. It was found that methine carbon resonances of PIPA split into triad sequences and those of PEA, PBA and PIBA show a mm triad at high field. Methylene carbon spectra of polyacrylates were assigned in terms of hexad sequences using HECTOR ( 13 C- 1 H COSY) spectra.

Coating and binder for pharmaceutical agents

Abstract: Coatings and binders for pharmaceutical forms containing a copolymerizate, wherein the copolymerizate is made up of: A) 10 to 25 wt % methacrylic acid; B) 40 to 70 wt % methyl acrylate; and C) 20 to 40 wt % methyl methacrylate; based on the total weight of the copolymerizate