Methyl acrylic acid copolymer latex

A 62 35 3 ethyl acrylate-methyl methacrylate-acrylic acid copolymer latex was prepared by continuous addition of the monomer mixture over a 4-hour period at 80° (22). The emulsifier was a sodium lauryl ether sulfate-nonylphenol polyoxyethylene adduct (20 moles ethylene oxide) mixture, the initiator a potassium persulfate-sodium hydroxulfite mixture, and the buffer a sodium bicarbonate-potassium hydroxide mixture. The final latex of pH 6.5 contained 40% solids, and the Tg of the copolymer was 13°. 

Butyl acrylate/methyl methacrylate/methacrylic acid copolymers with silylated latexes were prepared essentially according to a general procedure suitable to real-world systems. 

Many investigators have studied polymer surfaces for years [74,75] and have been successful in determining combinations of two or more valence states [76,77] by the mathematical process of deconvoluting the peak assignments [78]. It was only recently that latexes were examined by ESCA. Davies et al. [79] prepared a series of homopolymers of poly(methyl methacrylate) (PMMA) and poly(butyl methacrylate) (PBMA), and also poly[(methyl methacrylate)-co-(butyl methacrylate)] (PMMA-PBMA), by surfactant-free emulsion polymerization. It was found that the surface of the latex film was rich in PMMA, which may possibly be explained by the reactivity ratios for the MMA/BMA system (ri = 0.52 and rj = 2.11) [80], Recently, Arora et al. carried out angle-dependent ESCA studies on a series of films prepared from core-shell ionomeric latexes (with a polystyrene core and a styrene/n-butyl acrylate/ methacrylic acid copolymer shell) to determine the distribution of carboxyl groups in the films [81,82]. 

Latex with hydroxyl functionalised cores of a methyl methacrylate/butyl acrylate/2-hydroxyethyl methacrylate copolymer, and carboxyl functionalised shells of a methyl methacrylate/butyl acrylate/methacrylic acid copolymer was prepared by free radical polymerisation. The latex was crosslinked using a cycloaliphatic diepoxide added by three alternative modes with the monomers during synthesis dissolved in the solvent and added after latex preparation and emulsified separately, then added. The latex film properties, including viscoelasticity, hardness, tensile properties, and water adsorption were evaluated as functions of crosslinker addition mode. Latex morphology was studied by transmission electron and atomic force microscopy. Optimum results were achieved by introducing half the epoxide by two-step emulsion polymerisation, the balance being added to the latex either in solution or as an emulsion. 8 refs. 

The batch emulsion copolymerisation of vinyl acetate and acrylic acid, methyl acrylate and acrylamide was investigated at 25C with a redox initiator system and a complex emulsifier. The kinetic behaviour of the copolymerisation and the structure of the resulting copolymers, as well as the particle size and number density of the latexes, were studied as a function of the conversion and the reaction time. 10 refs. 

The monomers which have been investigated include methyl methacrylate, ethyl acrylate ester, hydroxy acrylates and methacrylates, acrylonitrile, vinyl acetate, vinyl chloride, acrylamide, vinylidene chloride, acrylic acid, vinyl pyrollidone and styrenec Many copolymer latexes of these monomers have also been preparedc Undoubtedly the most amenable system for model studies is methyl methacrylate in aliphatic hydrocarbono... 

Dispersions of copolymers of butadiene with acrylic acid or methacrylic acid in aqueous potassium hydroxide have been mentioned in the patent literature" as a dip for adhering rayon tire cord to rubber. The effect is most evident when carboxyl groups are present in the adhesive, the tie cement, and the cover stocks. The adhesive may be applied as latex, aqueous dispersion, or cement. A patent issued to the Dunlop Company Ltd." describes the use of a styrene-butadiene-itaconic acid copolymer with Gen-Tac Latex (GenCorp) in formulating an RFL (resorcinol formaldehyde latex) type adhesive for bonding a natural rubber compound to Nylon 66 and rayon tire cords. Brodnyan" also claims carboxylic adhesives for rayon, nylon, and Dacron cords. In this case, the tire cords were treated with a mixed polymer latex containing resorcinol-formaldehyde condensate, a butadiene-vinyl pyridine copolymer, an SBR copolymer, and a multifunctional copolymer from methyl acrylate, 2-hydroxy propyl methacrylate, and acrylic acid. A different approach was reported by Badenkov" whereby rayon or nylon tire cords were coated with... 

Acrylics. Acetone is converted via the intermediate acetone cyanohydrin to the monomer methyl methacrylate (MMA) [80-62-6]. The MMA is polymerized to poly(methyl methacrylate) (PMMA) to make the familiar clear acryUc sheet. PMMA is also used in mol ding and extmsion powders. Hydrolysis of acetone cyanohydrin gives methacrylic acid (MAA), a monomer which goes direcdy into acryUc latexes, carboxylated styrene—butadiene polymers, or ethylene—MAA ionomers. As part of the methacrylic stmcture, acetone is found in the following major end use products acryUc sheet mol ding resins, impact modifiers and processing aids, acryUc film, ABS and polyester resin modifiers, surface coatings, acryUc lacquers, emulsion polymers, petroleum chemicals, and various copolymers (see METHACRYLIC ACID AND DERIVATIVES METHACRYLIC POLYMERS). 

Copolymers containing allyl methacrylate have found application as an additive to other resin to enhance the properties of the system. For example, in one patent disclosure, an aqueous emulsion polymer was formed in water using 0.03 gm of sodium carbonate, 50 gm of methyl methacrylate, 2.0 gm of ethyl acrylate, and 0.1 gm of allyl methacrylate, and 0.40 gm of the sodium salt of an allyl Ci3-alkyl ester of sulfosuccinic acid. The polymerization was initiated with sodium persulfate and heated at 83°C for 1 hr. To this latex, 40 gm of butyl acrylate, 10 gm of styrene, 1.0 gm of allyl methacrylate, and another 0.40 gm of the above surfactant were added while polymerization continued. In a third... 

Muller and coworkers prepared disc-like polymer Janus particles from assembled films of the triblock copolymer SBM and, after hydrolysis of the ester groups into methacrylic acid units, used these as Pickering stabilizer in the soap-free emulsion polymerization of styrene and butyl acrylate [111]. Armes and coworkers described the synthesis of PMMA/siUca nanocomposite particles in aqueous alcoholic media using silica nanoparticles as stabilizer [112], extending this method to operate in water with a glycerol-modified silica sol [113, 114]. Sacanna showed that methacryloxypropyltrimethoxysilane [115] in the presence of nanosized silica led to spontaneous emulsification in water, which upon a two-step polymerization procedure afforded armored particles with an outer shell of PMMA [116]. Bon and coworkers demonstrated the preparation of armored hybrid polymer latex particles via emulsion polymerization of methyl methacrylate and ethyl methacrylate stabilized by unmodified silica nanoparticles (Ludox TM O) [117]. Performance of an additional conventional seeded emulsion polymerization step provided a straightforward route to more complex multilayered nanocomposite polymer colloids (see Fig. 14). 

In acrylic latices, the hard monomer is methyl methacrylate and the plasticizing monomer an acrylate, such as butyl acrylate or one of the acrylate comonomers mentioned above. Acrylic latices usually contain copolymers of acrylic or methacrylic acid as colloids and thickeners, these being solubilized by neutralization with base. Whatever the type of latex, coalescing solvents are also normally added to improve film formation. These may or may not be water miscible and include alcohols, glycols, ether-alcohols, ether-alcohol esters and even hydrocarbons, all of high boiled point. 

Polyurethane acrylate (PU-A) containing a double bond and COOH group was synthesised by the stepwise reaction of TDI, polyetherdiol, dimethylolpropionic acid (DMPA) and 2-hydroxypropyl acrylate (HPA). The PU-A was neutralised with triethylamine and self-emulsified in water to form the PU-A emulsion seed. The seeded emulsion copolymerisation of methyl methacrylate (MMA) onto the PU-A seed was carried out at 80C under soap-free conditions and an anionic latex of P(UA-MMA) was obtained. The structure of the P(UA-MMA) copolymer, its latex properties and the cast film were significantly affected by the amounts of HPA, DMPA and MMA. The results were discussed. 21 refs. 

The composition and microstracture of polymers in a latex system were studied by pyrolysis gas chromatography. The composition and microstructure of a polymer in the emulsion phase were identified by direct pyrolysis of the latex system, followed by comparing the trimer peak pattern with appropriate microstructure standards. The polymer in the aqueous phase was pre-pyrolysis derivatised with tetrabutylammonium hydroxide to convert the acid to its butyl ester. Similar procedures were then used to explore the composition and microstructure of the polymer in the aqueous phase. Polymers analysed included SCX-2660 (probably a styrene-methyl methacrylate-butyl acrylate terpolymer), styrene-butyl acrylate copolymer and styrene-alpha-methylstyrene-butyl acrylate terpolymer. 17 refs. 

An analysis presented of the forces contributing to the attraction and repulsion interactions between macromolecules in acrylate latices. The electrostatic repulsion forces, enthalpy and entropy effects, and the attraction forces from the expanded Hamaker equation are analysed. The influence of the structure of copolymers consisting of monomeric units of alkyl acrylate or methacrylate (methyl to n-butyl) and acryhc or methacryhc acid on the physico-chemical properties of the latices and their stabihty were determined. On the basis of experiments and calculations it was established that the stability of latices is decided by two mechanisms. The first (ionic stabilisation) consists in adsorption of anionic emulsifier particles, and the second (ionic-steric stabilisation) involves adsorption of such an emulsifier on an adsorption layer formed by the polymer macromolecules forming the latex. 25 refs. Articles from this journal can be requested for translation by subscribers to the Rapra produced International Polymer Science and Technology. 

In many cases latex products are composed of more than one monomer. In copolymerisation two or more monomers are built-in into the polymer chains. The copolymer chains are produced by simultaneous polymerisation of two or more monomers in emulsion. Emulsion copolymerisation allows the production of materials with properties which cannot be obtained by latex products consisting of one monomer, that is, homopolymer latexes, or by blending homopolymers. The properties of the materials required are usually dictated by the market. Nowadays, most of the material properties are achieved by combination of more than two monomers in the copolymer product. Typical industrial emulsion polymerisation formulations are mixtures of monomers giving hard polymers, and monomers leading to soft polymers. Styrene and methyl methacrylate are examples of monomers giving hard polymers, that is, polymers with a high glass transition temperature, Tg. Soft polymers, that is, polymers with a low Tg, are, for example, formed from -butyl acrylate. The industrial emulsion polymerisation formulations also contain small amounts of functional monomers such as acrylic and methacrylic acid to impart improved or special characteristics to the latex product. Note that the colloidal stability of the latex product can be seriously improved by acrylic and methacrylic acid. Furthermore, some applications may demand for the addition of other specialty monomers that make the kinetics of the copolymerisation even more complex. 

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