Polymethyl methacrylate esters

Contact lenses are the most common polymer product in ophthalmology. The basic requirements for this type of materials are (T)excellent optical properties with a refractive index similar to cornea good wettability and oxygen permeability ( ) biologically inert, degradation resistant and not chemically reactive to the transfer area ( ) with certain mechanical strength for intensive processing and stain and precipitation prevention. The common used contact lens material includes poly-P-hydroxy ethyl methacrylate, poly-P-hydroxy ethyl methacrylate-N-vinyl pyrrolidone, poly-P-hydroxy ethyl methacrylate, Poly-P-hydroxy ethyl methacrylate - methyl amyl acrylate and polymethyl methacrylate ester-N-vinyl pyrrolidone, etc. The artificial cornea can be prepared by silicon rubber, poly methyl... 

All of the eommereial alkyl eyanoaerylate monomers are low-viseosity liquids, and for some applications this can be an advantage. However, there are instances where a viseous liquid or a gel adhesive would be preferred, sueh as for application to a vertical surface or on porous substrates. A variety of viscosity control agents, depending upon the desired properties, have been added to increase the viscosity of instant adhesives [21]. The materials, which have been utilized, include polymethyl methacrylate, hydrophobic silica, hydrophobic alumina, treated quartz, polyethyl cyanoacrylate, cellulose esters, polycarbonates, and carbon black. For example, the addition of 5-10% of amorphous, non-crystalline, fumed silica to ethyl cyanoacrylate changes the monomer viscosity from a 2-cps liquid to a gelled material [22]. Because of the sensitivity of cyanoacrylate esters to basic materials, some additives require treatment with an acid to prevent premature gelation of the product. 

Cellulose Esters Epoxy Resins Lignins Polystyrene Poly (2-vinyl pyridine) Polyvinyl Chloride Polymethyl methacrylate Polyphenylene Oxide Phenolics Polycarbonate Polyvinyl Acetate, etc. Polyvinyl butyral SBR rubber, etc., etc. 

Formation of block polymers is not limited to hydrocarbon monomers only. For example, living polystyrene initiates polymerization of methyl methacrylate and a block polymer of polystyrene and of polymethyl methacrylate results.34 However, methyl methacrylate represents a class of monomers which may be named a suicide monomer. Its polymerization can be initiated by carbanions or by an electron transfer process, the propagation reaction is rapid but eventually termination takes place. Presumably, the reactive carbanion interacts with the methyl group of the ester according to the following reaction... 

The lack of solvent separated pairs raises the question whether some alternative mode of solvation should be considered. The ester group of the penultimate unit of the polymer, or the one preceeding it, could act as a solvating agent. The idea of intramolecular solvation was proposed by several workers in the field 37) and it is supported by the results of nmr studies of polymethyl methacrylate formed under various experimental conditions 38). Hypothetical structures such as those depicted below were proposed 39 h... 

Polymerization of t-butyl methacrylate initiated by lithium compounds in toluene yields 100% isotactic polymers 64,65), and significantly, of a nearly uniform molecular-weight, while the isotactic polymethyl methacrylate formed under these conditions has a bimodal distribution. Significantly, the propagation of the lithium pairs of the t-Bu ester carbanion, is faster in toluene than in THF. In hydrocarbon solvents the monomers seem to interact strongly with the Li+ cations in the transition state of the addition, while the conventional direct monomer interaction with carbanions, that requires partial dissociation of ion-pair in the transition state of propagation, governs the addition in ethereal solvents. 

Methyl methacrylate is only one of a family of monomers, including the various esters of acrylic, methacrylic, and ethacrylic acids, which are polymerized to produce the thermoplastic resins known as the acrylates. A wide variety of reactions and starting materials may be utilized for their production however, the principal commercial product is polymethyl methacrylate, sold by Du Pont and Rohm Haas under the trade names of Lucite and Plexiglas, respectively. These materials were introduced to the United States market in 1936 (44) and have received widespread acceptance due principally to their outstanding optical properties. Production in 1949 was reported as about 22,000,000 to 25,000,000 pounds and peak wartime capacity was above30,000,000 pounds. While this can account for only about 2% of the current production of propylene for chemical purposes, the acrylate resins are of considerable commercial importance as they are sold at a relatively high price and are the only materials available that will meet the requirements for certain military and civilian products. 

Literature continues to be rather extensive on this subject since the 1930s. A summarization is provided in this section. Products fabricated include sheets, films, rods and tubes, and embedment. Acrylic castings usually consist of polymethyl methacrylate (PMMA) or copolymers of this ester as the major component with small amounts of other monomers to modify the properties (Chapter 2). Adding acrylates or higher methacrylates lowers the heat deflection temperature and hardness and improves thermoformability and solvent cementing capability, with some loss in resistance to weathering. Dimethacrylates or other crosslinking monomers increase the resistance to solvents and moisture. 

In Chapter 5 we cited dynamic mechanical relaxation data for polymethyl methacrylate (PMMA). There it was shown that PMMA possesses two mechanical relaxation regions over the temperature range - 50° to 160°C at low frequencies. These were labeled a for the relaxation accompanying the glass transition and / for a secondary relaxation that has generally been associated with motions of the ester side group. PMMA has a predominantly nonpolar... 

Esters of methacrylic acid are obtained directly from acetone cyanohydrin by reaction of the latter with concentrated sulfuric acid to give methacrylamide sulfate, followed by reaction with an alcohol. The process is continuous and the methacrylamide sulfate is not isolated. Acetone cyanohydrin is derived from acetone and hydrogen cyanide (Pig. 15-39), Polymerization Procedures. Of particular importmice to the acrylics is the cast or bulk method of polymerization. This method is employed to produce cast polymethyl methacrylate sheets which are widely used in industrial applications. Careful control of polymerization is required to obtain a bubble-free product with good optical clarity. A typical flow sheet for the production of cast eet is shown in fig. lfi-40. Solution, suspension, and particularly emulsion polymerizations are also, widely used with the acrylics. Such polymerization reactions involve relatively conventional batch-type processes. i... 

Methacrylic acid, ethyl ester. See Ethyl methacrylate Methacrylic acid isobornyl ester. See Isobornyl methacrylate Methacrylic acid, isobutyl ester. See Isobutyl methacrylate Methacrylic acid, isodecyl ester. See Isodecyl methacrylate Methacrylic acid lauryl ester. See Lauryl methacrylate Methacrylic acid, methyl ester. See Methyl methacrylate Methacrylic acid methyl ester polymers. See Polymethyl methacrylate Methacrylic acid, monoester with 1,2-propanediol. See Flydroxypropyl methacrylate... 

Methyl-2-propenoic acid methyl ester. See Methyl methacrylate 2-Methyl-2-propenoic acid methyl ester homopolymer. See Polymethyl methacrylate... 

Methacrylic acid methyl ester polymers. See Polymethyl methacrylate Methacrylic acid, monoester with 1,2-propanediol. See Hydroxypropyl methacrylate... 

Propenoic acid, 2-methyl-, methyl ester, homopolymer. See Polymethyl methacrylate 2-Propenoic acid, 2-methyl methyl ester, polymer with 1,3-butadiene and butyl 2-propenoate CAS 33031-74-2... 

Miscellaneous Other modifications that can be made to cyanoacrylate adhesives include increasing viscosity by the addition of thickeners such as polymethyl methacrylate, cellulose esters or hydrophobic silicas. Colour can be imparted to the product by using selected dyes and pigments. 

Polymethacrylates n. A polymer of a methacrylic ester, polymethyl methacrylate being the most important and useful member of the class. 

Vinyl resins (1934) n. According to common chemical nomenclature, all resins and polymers made from monomers containing the vinyl group, H2C=CHX. In the chemical literature, polystyrene, polyolefins, polymethyl methacrylate and many other styrenic, ethenic, and acrylic co-polymers are classified as vinyls. In the plastics literature, the above materials are given their own classifications and the term vinyl is restricted to compounds in which X, above, is not H, a hydrocarbon radical, nor an acrylic-type ester. In daily use, the term vinyl plastics refers primarily to polyvinyl chloride and its co-polymers, and secondarily to the following polyvinyl acetal, polyvinyl acetate, poly-vinyl alcohol, polyvinyl but-yral, poly(n-vinylcar-bazole), polyvinyl dichloride, polyvinyl formal, polyvinylidene chloride, polyisobutylvinyl ether, and poly (1-vinylpyrrolidone). Mishra MKM, Yagd Y (1998) Handbook of vinyl polymerization. Marcel Dekker, New York. 

The changes and yields in polymer irradiation are often similar to those found with lower-molecular-weight compounds with similar structural features. The radiolysis of linear polyethylene is similar to that of the -alkanes, polystyrene resembles the alkylbenzenes, and polymethyl methacrylate behaves like a branched chain ester. Lower-molecular-weight compounds are often used to model processes taking place in polymer irradiation. 

Polyacrylate esters Polymethyl methacrylate Polyethyl methacrylate... 

The acrylics can be formulated as thermoplastic resins, thermosetting resins, and as a water emulsion latex. The resins are formed from polymers of acrylate esters, primarily polymethyl methacrylate and polyethyl acrylate. Since the acrylate resins do not contain tertiary hydrogens attached directly to the polymer backbone chain, they are esceptionally stable to oxygen and UV light. The repeating units for the methacrylate and acrylate are as follows ... 

It has been demonstrated using lETS [28] that when the ester-containing polymers polymethyl methacrylate and polyvinyl acetate are placed in contact with aluminium oxide, peaks which can be assigned to the carboxylate ion arise. Specifically, these are due to the symmetric and asymmetric vibrational modes of -COO which are located at about 1450 and 1610 cm F More recently, Devdas and Mallik [29] showed, using lETS, that a number of carboxylic acids adsorbed on alumina show such peaks an example is that pyruvic acid CH3CH2COCOOH shows the peaks at 1450 and 1605 cm . 

This technique has found the following applications in addition to those discussed in Sections 10.1 (resin cure studies on phenol urethane compositions) [65], 12.2 (photopolymer studies [66-68]), and 13.3 (phase transitions in PE) [66], Chapter 15 (viscoelastic and rheological properties), and Section 16.4 (heat deflection temperatures) epoxy resin-amine system [67], cured acrylate-terminated unsaturated copolymers [68], PE and PP foam [69], ethylene-propylene-diene terpolymers [70], natural rubbers [71, 72], polyester-based clear coat resins [73], polyvinyl esters and unsaturated polyester resins [74], polyimide-clay nanocomposites [75], polyether sulfone-styrene-acrylonitrile, PS-polymethyl methacrylate (PMMA) blends and PS-polytetrafluoroethylene PMMA copolymers [76], cyanate ester resin-carbon fibre composites [77], polycyanate epoxy resins [78], and styrenic copolymers [79]. 

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