Showing papers on "Methacrylic acid published in 1988"

Stability of Aqueous α-Al2O3 Suspensions with Poly(methacrylic acid) Polyelectrolyte

Abstract: Stability of aqueous α-Al2O3 suspensions with Na+ salt of poly(methacrylic acid) (PMAA-Na) polyelectrolyte was studied as a function of pH. At a given pH, the transition from the flocculated to the dispersed state corresponded to the adsorption saturation limit of the powders by the PMAA. As the pH was decreased, the adsorption saturation limit increased until insolubility and charge neutralization of the PMAA was approached. The critical amount of PMAA required to achieve stability is outlined in a stability map.

Processing of Highly Concentrated Aqueous α‐Alumina Suspensions Stabilized with Polyelectrolytes

Abstract: Stability and rheology of aqueous α-Al2O3 suspensions with poly(methacrylic acid) and poly(acrylic acid) polyelectrolytes were studied as a function of pH, solids loading, and molecular weight. Past work has found polyelectrolyte-stabilized suspensions to be fairly pH independent at low (e.g., 20 vol%) solids loadings. However, we now show that the effective pH range to provide dispersed and fluid suspensions narrows as the concentration of solids increases as related to interparticle forces. At high solids levels, the presence of excess polymer in solution has detrimental effects on stability, which increases as the molecular weight increases. Finally, with knowledge of these concepts, highly concentrated fluid suspensions of 60 vol% Al2O3 (>85 wt%) with submicrometer-size particles have been processed. Higher consolidated densities and reduced sintering temperatures are attained when compared with more conventional processing techniques.

Hydrogen bonding in polymer blends. 5. Blends involving polymers containing methacrylic acid and oxazoline groups

Abstract: Spectrometrie FTIR des melanges du copolymere ethylene/acide methacrylique avec le polymethylvinylether ou le copolymere oxyde d'ethylene/oxyde de propene

pH-Dependent Swelling and Solute Diffusion Characteristics of Poly(Hydroxyethyl Methacrylate–CO–Methacrylie Acid) Hydrogels

Abstract: Poly(hydroxyethyl methacrylate-co-methacrylic acid) hydrogels can swell extensively in a high-pH medium where the carboxyl groups are ionized. The swelling equilibrium is a strong function of the methacrylic acid composition of the polymer and pH of the medium. The nonionized gel structure was found to be rather insensitive to the amount of cross-linker, tetraethylene glycol dimethacrylate (TEGDMA), incorporated, within the range of 0.5 to 3%. This result is supportive of the existence of secondary interactions that shield the effect of covalent cross-links. Phenylpropanolamine (PPA) was used as a probe solute to study the diffusion characteristics of the poly(HEMA-co-MA) gels. Its diffusion coefficient in the swollen matrices of different methacrylic acid compositions at various pH's was measured via a desorption method. It is evident that these diffusion coefficients follow Yasuda's free volume theory, which expresses an exponential relationship between the solute diffusivity in a swollen polymer membrane and the reciprocal of the membrane hydration. Although interactions exist between PPA and the hydrogel matrix, these interactions are not significant enough to perturb the free volume relationship established. This observation can be explained by the high ionic strength of the system.

Adsorption of proteins from artificial tear solutions to contact lens materials.

Abstract: A series of polymers and copolymers of 2-hydroxyethyl methacrylate (HEMA) and methyl methacrylate (MMA) were synthesized in order to find surfaces that would adsorb minimal amounts of protein. The adsorption of albumin, lysozyme and immunoglobulin G from a three-way mixture of these proteins in isotonic buffered saline to the polymers was measured using /sup 125/I-labeled proteins. Apparently high protein uptake on copolymers rich in HEMA was found to be due to sorption of unbound /sup 125/I by the polymers. /sup 125/I sorption by the polymers was minimized by dialysis of the protein solution to remove unbound /sup 125/I iodide and inclusion of 0.01 M sodium iodide to block uptake of residual /sup 125/I iodide. Using these improved protocols, minimal total protein uptake was observed on copolymers containing 50% or more HEMA. The majority of adsorbed protein on all p(MMA-HEMA) polymers was albumin. Total protein uptake was greatest on pMMA. Commercial contact lenses composed of copolymers of HEMA and N-vinyl pyrrolidone (NVP) or acrylamide (AAm) adsorbed small amounts of all proteins whereas copolymers of methacrylic acid (MAAc) and HEMA adsorbed much larger quantities of lysozyme. These results indicate that protein uptake by contact lens materials varies greatly with polymer composition. Artifactuallymore » high adsorption can occur if precautions are not taken to prevent uptake of unbound /sup 125/I.« less

Novel polyamide reverse osmosis membranes

Abstract: An improved composite polyamide membrane and methods of making the membrane are described. This improved membrane is prepared using a cationic polymeric wetting agent in an aqueous solution containing a polyfunctional amine reactant which is interfacially polymerized with an acyl halide to form a thin film polyamide discriminating layer on a microporous support. Alternatively, the wetting agent can be applied directly to the substrate and the interfacial polymerization can occur on said treated substrate. The resulting membrane exhibits an unexpected combination of high water flux, high rejection of divalent anion salts, variable sodium chloride rejection and good caustic resistance at low operating pressures. In one embodiment of this invention, a porous substrate is first treated with an aqueous piperazine solution containing a copolymer of vinylbenzyl dimethyl sulfonium chloride and methacrylic acid and then the coated microporous support is contacted with trimesoyl chloride in an organic solvent.

Analysis of polymer surfaces by SIMS. 12. On the fragmentation of acrylic and methacrylic homopolymers and the interpretation of their positive and negative ion spectra

Abstract: The positive and negative ion spectra from homologous series of alkyl methacrylate, hydroxyalkyl methacrylate and alkyl acrylate polymers; poly (methacrylic acid) and poly(methacrylic anhydride) are reported. A systematic interpretation of the spectra can be accomplished on the basis of fragmentation pathways consistent with the known effects of other ionizing radiations. The negative ion spectra, previously little studied, are a powerful probe of structure for this class of polymer.

Process for providing polyamide materials with stain resistance with sulfonated novolak resin and polymethacrylic acd

Abstract: A treated fibrous polyamide substrate having resistance to staining by acid colorants is provided. The treated substrate comprises a fibrous polyamide substrate having applied thereto (a) a partially sulfonated novolak resin and (b) polymethacrylic acid, copolymers of methacrylic acid, or combinations of said polymethacrylic acid and said copolymers of methacrylic acid.

Radiation-curable acrylates

Abstract: Radiation-curable catalysts are obtainable by reacting A) 1 equivalent of a dihydric to hexahydric oxyalkylated C2 -C10 -alcohol with B) from 0.05 to 1 equivalent of a dibasic to tetrabasic C3 -C36 -carboxylic acid or its anhydride and C) from 0.1 to 1.5 equivalents of acrylic acid and/or methacrylic acid and reacting the excess carboxyl groups with an equivalent amount of epoxide compound, and are used in radiation-curable coating materials.

Fine polishing composition for wafers

Abstract: A fine polishing composition for wafers, comprising water, particulate amorphous silica and a polysaccharide polymer graft-polymerized with acrylamide alone or together with at least one vinyl monomer selected from the group consisting of acrylic acid, methacrylic acid and styrenesulfonic acid, and adjusted with an alkaline substance to a pH of from 8 to 12.

Use of graft polymers based on polyalkylene oxides as grayness inhibitors in the wash and aftertreatment of textile material containing synthetic fibers

Abstract: A detergent contains as a grayness inhibitor in the wash and aftertreatment of textile material containing synthetic fibers a graft polymer obtainable by grafting (a) a polyalkylene oxide which has a number average molecular weight of from 300 to 100,000 and is based on ethylene oxide, propylene oxide and/or butylene oxide with (b) N-vinlypyrrolidone and (c) a vinyl ester derived from a saturated monocarboxylic acid containing from 1 to 6 carbon atoms and/or a methyl or ethyl ester of acrylic or methacrylic acid in a weight ratio (a):(b):(c) of from 1:0.3:1 to 1:5:30, the order of the addition of (b) and (c) in the graft copolymerization being immaterial and it being possible for up to 1 mole % of the grafted-on monomers (c) to be hydrolyzed.

Kinetic investigation of methacrylic acid synthesis on hetropoly-compounds†

Abstract: The kinetics of heterogeneously catalyzed methacrylic acid synthesis from isobutyric acid has been investigated. Initial catalyst screening pointed to 10-molybdo-2-vanado-phosphoric acid and its Cs-salts as the most promising catalysts. A model describing the reaction behaviour of all the different hetropoly-compounds used in this work was developed. A relationship was found between model parameters and composition of different catalysts. First insight was gained into the catalyst deactivation phenomena. Deactivation appears to be caused mainly by loss of molybdenum with simultaneous collapse of the Keggin structure.

Emulsifier-free emulsion copolymerization of styrene and butyl acrylate. II. Kinetic studies in the presence of ionogenic comonomers

Abstract: Batch emulsifier-free copolymerizations of styrene (S) and butyl acrylate (BuA) have been performed for a S/BuA weight ratio = 50/50 in the presence of two types of functional comonomers [methacrylic acid (MAA) at different pHs] or potassium sulfopropylmethacrylate (SPM) and two initiators [potassium persulfate or 4–4′azobiscyanopentanoic acid (AZO)]. The use of AZO/MAA system results in the formation of polymer particles with only surface carboxylic end groups. The particle size of the final latexes can be adjusted with the MAA concentration, provided the polymerization is carried out at pH > 6.5. However, the higher the MAA concentration, the sooner the polymerization levels off in conversion. With the K2S2O8/SPM system, particles bearing only sulfate and sulfonate groups are produced and the polymerization is complete. In that case, the particle size of the final latexes is smaller than with the previous system and 30% of the SPM is fixed on the particle surface, instead of 10% with MAA. Using SPM, a too high functional monomer concentration results in the latex destabilization caused by the formation of a large amount of polyelectrolytes. Kinetic studies indicate that most of the functional monomer is incorporated onto the particle surface during the last 30% conversion of the polymerization. A tentative explanation of such a behavior is discussed, based on the existence of two polymerization loci in the latex system.

Emulsion polymerized cohesive polymer latex useful as cold seal coating and improved sealable articles treated with the same

Abstract: A cold sealable emulsion polymerized terpolymer cohesive formulation which has low surface tack characteristics, prepared from the emulsion polymerization of a first monomer selected from the group consisting of ethyl acrylate, hexyl acrylate, isooctyl acrylate, butyl acrylate, methyl acrylate and vinylidene chloride, a second monomer selected from the group consisting of vinyl acetate, methyl methacrylate, styrene, ethyl methacrylate and isobutyl methacrylate and a third monomer selected from the group consisting of methacrylic acid, acrylic acid, itaconic acid, sulfoethyl methacrylate and malic acid with the proviso that each of said first, second and third monomers are different.

Water-soluble polymer

Abstract: PURPOSE:To obtain a polymer which is soluble in tap water but insoluble in an aqueous solution containing at least 05% of neutral inorganic salts consisting of monovalent ions, such as NaCl, by copolymerizing (meth)acrylic acid with its alkyl ester wherein a specified amount of (meth)acrylic acid is in salt form CONSTITUTION:This water-soluble polymer is a copolymer of acrylic and/or methacrylic acid (A) and at least one member (B) of monomers selected from the group consisting of alkyl acrylate and alkyl methacrylate having 1-18C alkyl groups, where A/B=1/9-9/1 (ratio by weight) 2-70mol% of the constituent acrylic or methacrylic acid is in salt form The alkalis for neutralization include ethanolamines or preferably sodium or potassium hydroxide and ethanolamines which should be used together

Photochemical Production of Carboxylic Acids in a Remote Continental Atmosphere

Abstract: Model calculations are conducted to investigate the production of carboxylic acids from photochemical decomposition of isoprene, one of the main natural hydrocarbons emitted from vegetation. Both gas-phase and aqueous-phase chemical reaction pathways are examined. A simple dynamical model is proposed to simulate the boundary layer of the Amazon rain forest, and model predictions are compared to measurements made in that region in July 1985. It is found that formic acid, methacrylic acid, and pyruvic acid can be produced in significant quantities by gas-phase decomposition of isoprene. In the Amazon basin, this source may yield concentrations of these acids in the order of 1 ppb, 0.1 ppb, and 0.02 ppb, respectively. Production of formic acid in cloud by aqueous-phase oxidation of CH2O does not greatly increase the formic acid concentration predicted from the gas-phase mechanism; cloud droplets with pH > 4 are actually expected to constitute net sinks for formic acid. No significant production of acetic acid is expected from the photochemical decomposition of isoprene. Comparisons of model predictions with field data indicates that isoprene could be a major source of formic acid and pyruvic acid observed in the gas phase and in rainwater; however, acetic acid must originate from another source.

Photophysical properties of pyrene covalently bound to photoelectrolytes

Abstract: Copolymers of methacrylic acid, acrylic acid, and poly(styrenesulfonate) have been prepared with small mole fractions of 1-vinylpyrene. The fluorescence properties and quenching efficiencies in water have been measured for high and low pH with methylviologen, sulfonated propylmethylviologen, and a neutral zwitterionic viologen. It has been found that static (or contact) quenching plays a significant role. Formation of a pyrene-viologen charge-transfer complex was observed at high and low pH. Charge separation following redox quenching does not occur for the viologens, unlike the analogous vinyldiphenylanthracene polymers. The absence of charge separation is tentatively ascribed to the formation of a relatively tightly bound complex during the quenching event.

Characterization of poly(carboxylic acid)/poly(ethylene oxide) blends formed through hydrogen bonding by spectroscopic and calorimetric analyses

Abstract: The solid state of the complex between poly(acrylic acid) (PAA) and poly(ethylene oxide) (PEO), and that between poly(methacrylic acid) (PMAA) and PEO formed via hydrogen-bonding was studied by differential-scanning calorimetric (DSC) and by Fourier-transform infrared (FT–IR) spectroscopic measurements. Melting temperature Tm and the degree of the crystallinity Xc of PEO in the systems PAA (or PMAA)/PEO blends obtained from aqueous or dimethyl sulfoxide (DMSO) medium were measured in various unit mol % of PEO ([PEO]100/{[PAA(or PMAA)] + [PEO]}) where [ ] is the unit mole concentration. It was found that 50 unit mol % of PEO is a critical composition, which gives new evidence for the 1 : 1 complex formation between PAA (or PMAA) and PEO. From the FT–IR spectroscopic analysis in conjunction with DSC measurements we also found that the effects of solvent and of hydrophobic interaction (due to the α-methyl group of PMAA) are the important factors controlling the complexation in the solution and solid systems. These factors also affect the crystallization behavior and the microstructure of the PAA (or PMAA)/PEO blend in solid state.

Gas permeable contact lens and method and materials for its manufacture

Abstract: A polymer is prepared by forming a mixture of 3-methacryloxypropytris(trimethylsiloxy) silane, methacrylic acid, cyclohexylmethacrylate, 2-hydroxypropylmethacrylate, m,p-styrylethyltrimethoxysilane, methyl methacrylate and a cross linker. A polymerization initiator is added to the mixture, and UV or thermal energy is supplied so that the mixture polymerizes to form a polymer that is transparent, hard, machinable and oxygen permeable. The polymer is cut into lenses, and the lenses are treated with acetyl chloride or another suitable chemical so that their surfaces become hydrophilic. The result is oxygen-permeable, hydrophilic, daily and extended-wear, hard contact lenses.

Process for coating wood, wood materials and paper

Abstract: The invention relates to a process for coating wood, wood materials and paper in which a radiation-curable coating composition is applied and cured by means of UV rays or electron beams. The film-forming component employed in the coating compositions comprises polyester acrylates and/or polyester methacrylates which can be prepared by esterifying polyesters or polyethers carrying at least two free hydroxyl groups per molecule and having number average molecular weights of between 400 and 4000 by means of from 100 to 150 mol%, based on the OH group of the polyester or polyether, of acrylic acid and/or methacrylic acid with acidic catalysis and with azeotropic removal of the water of reaction. After the esterification catalyst has been neutralised, the residual acrylic or methacrylic acid is reacted with an epoxide compound containing at least two epoxide groups per molecule. The entrainer is then removed by distillation together with residual acrylic or methacrylic acid. The invention also relates to the process for the preparation of the polyester (meth)acrylates and to the use of these polyester (meth)acrylates in radiation-curable coating compositions.

Addition products from acrylates and amines, and their use in radiation-curable masses

Abstract: Addition products composed of A) an ester of acrylic acid and/or methacrylic acid and a monohydric alcohol with B) a primary monoamine having a molar ratio of monoamine to acrylic double bond of the ester of 0.05:1 to 0.4:1 are used in radiation- curable coating materials and printing inks.

Experimental implantation of hydrogel into the bone.

Abstract: The present study deals with the application and possibilities of insoluble hydrophilic gels (poly(2-hydroxyethyl methacrylate)) as substitutes of bone tissue experimentally. Their biocompatibility is examined with regard to the porous qualities of the implant and to its chemical structure, and their behavior in the cancellous and compact bone is evaluated. It was found that the modifications of hydrogels used in the experiment are biocompatible, with the compatibility increasing in proportion to increasing porosity. The nonporous and microporous hydrogels are not compatible and are demarcated. The sintered macroporous gel is surrounded by a thin fibrin membrane. By adding methacrylic acid to the hydrogel surface, adhesion increases markedly. Marked destruction also appears in the polymer especially in the cancellous bone. By an active destruction of the polymer, no direct phagocytosis can be proved. Upon breakdown of the implant in the compact bone the activity of the macrophages is delayed. When the gel without methacrylic acid is used alone, destruction does not occur even after 193 days. When methacrylic acid is added to the polymer surface, destruction does occur and the implant is filled only by bone trabeculae.

Shear stable multirange oils having an improved viscosity index

Abstract: Multirange lubricating oils having high shear stability comprising paraffinic oils as their base and containing, as an additive improving the viscosity index, a mixture of at least two different polymer species, each of said polymer species being composed of monomers selected from the group consisting of (a) esters of methacrylic acid and acrylic acid with linear alcohols having 6 to 15 carbon atoms, (b) esters of methacrylic acid and acrylic acid with linear alcohols having from 16 to 30 carbon atoms, (c) esters of methacrylic acid and acrylic acid with branched alcohols having from 6 to 40 carbon atoms, (d) esters of methacrylic acid and acrylic acid with alcohols having from 1 to 5 carbon atoms, and (e) other monomers, different from (a)-(d), susceptible to free-radical copolymerization, and containing functional groups in the molecule, monomer or monomers (a) being from 0 to 100 mole percent of said polymer species, monomer(s) (b) being from 0 to 10 mole percent, monomers (c), (d) and (e) combined being from 0 to 100 mole percent, and monomers (a) to (e) combined being 100 mole percent of said polymer species, said individual polymer species differing from one another by at least 10 mole percent with respect to their content of component (a).

Characteristic Ratios of Polymethacrylates

Abstract: Dilute solution properties of polymethacrylates have been studied extensively over the past 30 or so years. Probably more different polymethacrylates have been prepared and characterized than any other class of polymer. A major reason for this intense interest is the ease with which various methacrylate monomers can be prepared, e.g., by esterification of methacrylic acid with the appropriate alcohol or trans-esterification of methyl methacrylate. Also, most methacrylate monomers are easily polymerized to high molecular weights by free radical methods in bulk, in dilute solution, or in emulsion. These polymerizations are generally free of chain transfer reactions which lead to branching or cross linking, so long as conversion to polymer is kept at fairly low levels. Many methacrylates also polymerize via anionic mechanisms. Thus, linear polymethacrylates with a wide variety of side groups can be readily prepared.

Press felt conditioner for neutral and alkaline papermaking systems

Abstract: This invention relates to an improved press felt conditioning treatment which controls the deposition of polymerically flocculated particulate substances in a press felt. The treatment comprises applying to the felt an effective inhibiting amount of a conditioner comprising a relatively low molecular weight organic, anionic polymer and at least one hydrophilic, nonionic or anionic surfactant. The polymer preferrably has an acrylic acid or methacrylic acid functionality and is preferrably selected from the group consisting of homopolymers of acrylic acid, a methacrylic acid/polyethylene glycol allyl ether copolymer, a homopolymer of methacrylic acid, an acrylic acid/polyethylene glycol allyl ether copolymer, and an acrylic acid/1-allyloxy-2-hydroxypropane sulfonic acid copolymer. The surfactant is preferrably selected from the group consisting of octyl phenol ethoxylate, nonyl phenol ethoxylate, dodecyl phenol ethoxylate, secondary alcohol ethoxylate, ethoxylated polyoxypropylene glycol, dialkyl phenol ethoxylate, alkyl polyglycoside, dodecylbenzene sulfonic acid and polyoxyethyelene sorbitan monoester. The use of a relatively low molecular weight polymer having an acrylic acid or methacrylic acid functionality in combination with at least one hydrophilic, nonionic or anionic surfactant is especially effective at preventing the deposition of polymerically flocculated particulate substances in a press felt and papermaking machine.

Floor polishing and coating composition

Abstract: An aqueous cleaning, coating and polishing composition consisting essentially of 1 to 20% by weight of a water insoluble alkali soluble addition polymer comprising at least one hydrophilic monomer selected from acrylic acid and methacrylic acid and at least one hydrophobic monomer selected from alkyl acrylate and alkyl methacrylate, where alkyl has from 1 to 6 carbon atoms, and at least one hydrophobic monomer selected from styrene and monoalkylstyrene where monoalkyl has from 1 to 6 carbon atoms, 1 to 13% by weight of an alkyli soluble 2:1 to 3:1 styrene:acrylic acid resin, 5 to 15% by weight of a fugitive plasticizer, 1 to 3% by weight of a permanent plasticizer, 0.01 to 0.05% by weight of an anionic or nonionic fluorocarbon surfactant leveling agent, 0.0003 to 0.003% by weight of a dimethylpolysiloxane antifoaming agent; 0.0003 to 0.003% by weight of a 1,2-benzoisothiazol-3(2H)-one or 3(2H)-isothiazolone preservative, ammonia to provide a pH of 8.0 to 9.6 and water q.s. to 100%, the composition having a content of solids of from 10 to 25% by weight.