Acetate - Methyl Methacrylate Copolymer

In this example, a copolymer of vinyl acetate (VA) and methyl methacrylate (MMA) is formed. As in the last example, a single surfactant and initiator are used and added to these are a buffer and a protective colloid. 

Nitrogen is not required as the vapour pressure of vinyl acetate monomer ensures that an oxygen free atmosphere exists above the reactants. The reactivity ratio s for vinyl acetate and methyl methacrylate indicate that MMA is 20-40 times more reactive towards free radicals than is VA. 

The initial period of 30 minutes refluxing produces some copolymer rich in MMA and the addition of the balance of the monomer mixture at a rate rqrproximating to that of the polymerisation ensures a random copolymer approximating 73% by weight of VA is formed. The use of a protective colloid (hydroxy ethyl cellulose) is partially responsible for the larger particle size compared to the methyl methacrylate homopolymer in the previous example. 

A solution of hydroxy ethyl cellulose is made in de-ionised water. To this solution is added the sodium dodecylbenzene sulphonate, ammonium acetate and ammonium persulphate. 

25% cf the vinyl acetate and 16% of the methyl methacrylate are added and the reaction vessel is heated to the reflux temperature of the vinyl acetate (the reflux will occur at ca 67°C). 

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An a priori method for choosing a surfactant was attempted by several researchers (50) using the hydroph i1 e—1 ip oph i1 e balance or HLB system (51). In the HLB system a surfactant soluble in oil has a value of 1 and a surfactant soluble in water has a value of 20. Optimum HLB values have been reported for latices made from styrene, vinyl acetate, methyl methacrylate, ethyl acrylate, acrylonitrile, and their copolymers and range from 11 to 18. The HLB system has been criticized as being imprecise (52). 

Figure 3. Time dependence of the fraction R of unreacted aminostyrene residues during acetylation by 0.14 M acetic anhydride at 30°C. Methyl methacrylate copolymer in acetonitrile solution (0) linear poly-(methyl methacrylate-co-butyl methacrylate) swollen with acetonitrile Cd) methyl methacrylate copolymer crosslinked with 1 mole% ( ) and with 15 mole% ( ) ethylene dimethacrylate poly(methacrylate crosslinked with 3 mole% ethylene dimethacrylate containing entrapped poly(methyl acrylate-co-aminostyrene) ( ).

It has been reported that in ethyl acetate and dichloroethane solution, the position of the excimer band is concentration dependent The interpretation of solvent effects is complex. Since the compactness of the pdymer coil will affect the efficiency of energy migration and the ccmcentration of aromatic species in conformations suitable for excimer formation, sdvent effects are to be expected in polymers in which excimer formation is the result of nearest-neighbour interactions, as is the case in styrene as shown in studies on styrene-methyl methacrylate copolymers ... 

FIGURE 12.14 Response of the major equatorial reflection to incorporation of the following comonomers in copolymers with acrylonitrite vinyl acetate, methyl methacrylate, and methacrylonitrile. (From Bell, J.F. and Murayama, T., J. Appl. Polym. Sci. 12, 1795, 1968.)... 

The NMR method has been extremely successful when applied to sequencing addition copolymers with carbon atom backbone, such as ethylene, propylene, butadiene, acrylonitrile, vinyl acetate, methyl methacrylate, styrene, methylstyrene, vinyl chloride, vinyl fluoride (in this case, F-NMR can be used). " Condensation copolymers such as polyurethanes, polyesters, and polyamides have been analyzed by and NMR. cellent reviews have appeared on this topic, the literature on the subject is always growing, and the instrumental progress is fast. ... 

Sucrose benzoate/sucrose acetate isobutyrate/butyl benzyl phthalate/methyl methacrylate copolymer... 

Styrene/butadiene polymer Styrene/methyl methacrylate copolymer Styrene/a-methyl styrene resin Tall oil rosin Tallow amide Terpene resin Tetrasodium pyrophosphate Trimethylolpropane Urea-formaldehyde resin Urea-formaldehyde resin, butylated Vinyl chloride/vinyl acetate copolymer Vinyl chloride/vinylidene chloride copolymer coatings, food-contact acrylate ester copolymer Sodium borate... 

Styrene/allyl benzoate copolymer Styrene/MA copolymer Styrene/PVP copolymer Sucrose acetate isobutyrate Sucrose benzoate Sucrose benzoate/sucrose acetate isobutyrate/butyl benzyl phthalate copolymer Sucrose benzoate/sucrose acetate isobutyrate/butyl benzyl phthalate/methyl methacrylate copolymer Sucrose benzoate/sucrose acetate isobutyrate copolymer TEA-acrylates/acrylonitrogens copolymer Tosylamide/epoxy resin Tosylamide/formaldehyde resin Triacetin Tributyl citrate Tricetyl phosphate Tricontanyl PVP... 

Acetal homopolymer Animal glue Calcium resinate 1-Decene, homopolymer, hydrogenated Glyceryl rosinate Hydrogenated rosin Methyl rosinate Pentaerythrityl rosinate Polyethylene, chlorosulfonated Polyphenylene ether Potassium rosinate Sodium rosinate Tall oil rosin Vinylidene chloride/methyl acrylate/methyl methacrylate copolymer food-contact articles, for repeated use Butadiene/acrylonitrile copolymer EPM rubber Epoxy, bisphenol A/epichlorohydrin Ethylene/propylene/dicyclopentadiene terpolymer Hexafluoropropylene/vinylidene fluoride copolymer Hexafluoropropylene/vinylidene fluoride/tetrafluoroethylene terpolymer Hydrogenated butadiene/acrylonitrile... 

In a study of the flame retardance of styrene-methyl methacrylate copolymer with covalently bound pyrocatechol-vinyl phosphate, diethyl p-vinyl benzyl phosphonate, or di(2-phenyl ethyl phosphonate) groups. Ebdon and co-workers [23] obtained data on their decomposition behaviour. This was achieved by reducing the rate of liberation of flammable methyl methacrylate monomer during combustion. Possible mechanisms for these processes are suggested. Other methacrylate copolymers which have been the subject of thermal degradation studies include PMMA-N-methylmaleimide-styrene [24] and PMMA-ethylene vinyl acetate [25-27]. 

Figure 2. Thermal cis-trans isomerization of methyl methacrylate copolymer with 0.9 mole % of p-(N-methacrylyl)aminoazobenzene at 60 C after photochemical trans-cis isomerization at the same temperature (zr. )bulk polymer, (O)polymer plasticized with 30% dioctyl phthalate,( )dilute solution in butyl acetate.

Over the last few years a number of applications on the analysis of olefin copolymers have been published that make use of the LC-Transform system. These include the SEC-FTIR analysis of ethylene/vinyl acetate copolymers [117], ethylene/ methyl methacrylate copolymers [118, 119], ethylene/styrene copolymers [120], HOPE and PP [121]. A number of studies used SEC-FTIR for monitoring the thermo-oxidative degradation of polyolefins [122-126] and a combination of TREE and SEC-FTIR to investigate the complex structure of olefin copolymers [127,128]. 

For example, this method was carried out for various copolymers, namely styrene-methyl methacrylate copolymer [65-67], epoxide resins [68], styrene-acrylic acid copolymer [69], styrene-2-methoxyethyl methacrylate copolymer [70, 71], ethylene-ot-olefin copolymer [72], partially modified dextran-ethyl carbonate copolymer [73], vinyl chloride-vinyl acetate copolymer [43], styrene-acrylonitrile copolymer [74], and styrene-butadiene copolymer [75]. 

A number of methods such as ultrasonics (137), radiation (138), and chemical techniques (139—141), including the use of polymer radicals, polymer ions, and organometaUic initiators, have been used to prepare acrylonitrile block copolymers (142). Block comonomers include styrene, methyl acrylate, methyl methacrylate, vinyl chloride, vinyl acetate, 4-vinylpyridine, acryUc acid, and -butyl isocyanate. 

Other Polymers. Besides polycarbonates, poly(methyl methacrylate)s, cycfic polyolefins, and uv-curable cross-linked polymers, a host of other polymers have been examined for their suitabiUty as substrate materials for optical data storage, preferably compact disks, in the last years. These polymers have not gained commercial importance polystyrene (PS), poly(vinyl chloride) (PVC), cellulose acetobutyrate (CAB), bis(diallylpolycarbonate) (BDPC), poly(ethylene terephthalate) (PET), styrene—acrylonitrile copolymers (SAN), poly(vinyl acetate) (PVAC), and for substrates with high resistance to heat softening, polysulfones (PSU) and polyimides (PI). 

Block copolymers of vinyl acetate with methyl methacrylate, acryflc acid, acrylonitrile, and vinyl pyrrohdinone have been prepared by copolymeriza tion in viscous conditions, with solvents that are poor solvents for the vinyl acetate macroradical (123). Similarly, the copolymeriza tion of vinyl acetate with methyl methacrylate is enhanced by the solvents acetonitrile and acetone and is decreased by propanol (124). Copolymers of vinyl acetate containing cycHc functional groups in the polymer chain have been prepared by copolymeriza tion of vinyl acetate with A/,A/-diaIlylcyanamide and W,W-diaIl5lamine (125,126). 

Group-Transfer Polymerization. Living polymerization of acrylic monomers has been carried out using ketene silyl acetals as initiators. This chemistry can be used to make random, block, or graft copolymers of polar monomers. The following scheme demonstrates the synthesis of a methyl methacrylate—lauryl methacrylate (MMA—LMA) AB block copolymer (38). LMA is CH2=C(CH2)COO(CH2) CH2. 

The important features of rigidity and transparency make the material competitive with polystyrene, cellulose acetate and poly(methyl methacrylate) for a number of applications. In general the copolymer is cheaper than poly(methyl methacrylate) and cellulose acetate, tougher than poly(methyl methacrylate) and polystyrene and superior in chemical and most physical properties to polystyrene and cellulose acetate. It does not have such a high transparency or such food weathering properties as poly(methyl methacrylate). As a result of these considerations the styrene-acrylonitrile copolymers have found applications for dials, knobs and covers for domestic appliances, electrical equipment and car equipment, for picnic ware and housewares, and a number of other industrial and domestic applications with requirements somewhat more stringent than can be met by polystyrene. 

Because the polymer degrades before melting, polyacrylonitrile is commonly formed into fibers via a wet spinning process. The precursor is actually a copolymer of acrylonitrile and other monomer(s) which are added to control the oxidation rate and lower the glass transition temperature of the material. Common copolymers include vinyl acetate, methyl acrylate, methyl methacrylate, acrylic acid, itaconic acid, and methacrylic acid [1,2]. 

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