Copolymer methyl methacrylate

Figure 7.6 Chemical shift (from hexamethyldisiloxane) for acrylonitrile-methyl methacrylate copolymers of the indicated methyl methacylate (Mj) content. Methoxyl resonances are labeled as to the triad source. [From R. Chujo, H. Ubara, and A. Nishioka, Polym. J. 3 670 (1972).]...

Suspension Polymerization. Suspension polymerisation yields polymer in the form of tiny beads, which ate primarily used as mol ding powders and ion-exchange resins. Most suspension polymers prepared as mol ding powders are poly(methyl methacrylate) copolymers containing up to 20% acrylate for reduced btittieness and improved processibiUty are also common. 

I ew Rubber-Modified Styrene Copolymers. Rubber modification of styrene copolymers other than HIPS and ABS has been useful for specialty purposes. Transparency has been achieved with the use of methyl methacrylate as a comonomer styrene—methyl methacrylate copolymers have been successfully modified with mbber. Improved weatherability is achieved by modifying SAN copolymers with saturated, aging-resistant elastomers (88). 

The dynamic mechanical properties of VDC—VC copolymers have been studied in detail. The incorporation of VC units in the polymer results in a drop in dynamic modulus because of the reduction in crystallinity. However, the glass-transition temperature is raised therefore, the softening effect observed at room temperature is accompanied by increased brittleness at lower temperatures. These copolymers are normally plasticized in order to avoid this. Small amounts of plasticizer (2—10 wt %) depress T significantly without loss of strength at room temperature. At higher levels of VC, the T of the copolymer is above room temperature and the modulus rises again. A minimum in modulus or maximum in softness is usually observed in copolymers in which T is above room temperature. A thermomechanical analysis of VDC—AN (acrylonitrile) and VDC—MMA (methyl methacrylate) copolymer systems shows a minimum in softening point at 79.4 and 68.1 mol % VDC, respectively (86). 

Latices of butadiene-methyl methacrylate copolymer have been used in paper and board finishes. 

Besides the MBS materials, related terpolymers have been prepared. These include materials prepared by terpolymerising methyl methacrylate, acrylonitrile and styrene in the presence of polybutadiene (Toyolac, Hamano 500) methyl methacrylate, acrylonitrile and styrene in the presence of a butadiene-methyl methacrylate copolymer (XT Resin), and methylacrylate, styrene and acrylonitrile on to a butadiene-styrene copolymer. 

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) ( ).

F.C. Y.Wang and P.B. Smith, Quantitative analysis and structure determination of styrene/ methyl methacrylate copolymers by pyrolysis gas chromatography, Anal. Chem., 68, 3033 3037(1996). 

GUTHRIE AND HOWARD Styrene and Methyl Methacrylate Copolymers 299... 

Poly[2-(dimethylamino)ethyl methacrylate-block- methyl methacrylate] copolymer, 20 485... 

A study was made of the thermal degradation behaviour of PS foams used as patterns in the lost foam process for metal casting. The data indicated that the thermal degradation of the pattern had a strong effect on mould filling and casting quality. The use of other types of foam such as PE, PP, PMMA and styrene-methyl methacrylate copolymers to overcome problems encountered with PS foam patterns is discussed. 7 refs. 

Styrene-methyl methacrylate copolymer PVC sheets Aramid nylon Polyurethane foam LDPE resin Ethylene-propylene... 

Kenawy 64) immobilized ammonium and phosphonium peripheral functionalized dendritic branches on a montmorillonite supported chloromethylstyrene/methyl methacrylate copolymer (74-75). These polymer/montmorillonite-supported dendrimers were used as phase transfer catalysts (PTC) for the nucleophilic substitution reaction between -butyl bromide and thiocyanate, cyanide, and nitrite anions in a toluene or a benzene/water system. These PT catalysts could be recycled by filtration of the functionalized montmorillonite from the reaction mixture. Generally,... 

IR analysis shows that double bonds were absent in the product within the range of an experimental error. The reaction product is composed of ladder blocks and the blocks of styrene units. In order to verify this structure, hydrolysis of the product was carried out in methanol-benzene and methanol solutions of KOH. After the hydrolysis, the product was esterified by diazomethane and styrene-methyl methacrylate copolymer was separated. The expected scheme of these reactions is as follows ... 

Table 3. Influence of monomeric arrangements of styrene-methyl methacrylate Copolymers upon R f valuesc...

More quantitative studies have shown that, although some hypochromism effects exist, they are small. For example, Monnerie I9) examined the integrated molar extinction coefficient of atactic PS in chloroform and found only a 2 % decrease for the polymer relative to ethyl benzene. In addition, Vala and Rice 15 reported a 10% decrease in absorption for the 260 nm band of isotactic PS relative to atactic PS, which was qualitatively confirmed by Longworth18>. Similarly, Cantow 8> observed a 4% hypochromism of the 261.5 nm band of isotactic PS in dioxane relative to atactic PS. Finally, Cantow 8) observed strong hypochromism (relative to atactic PS) ranging from 19% at 262 nm to 32% at 269 nm for an alternating styrene-methyl methacrylate copolymer and for random copolymers having a low styrene content. 

A similar but smaller intramolecular quenching effect was seen by Phillips and co-workers 44,4S) for 1-vinylnaphthalene copolymers incapable of excimer fluorescence. The monomer fluorescence lifetime of the 1-naphthyl group in the methyl methacrylate copolymer 44) was 20% less than the lifetime of 1-methylnaphthalene in the same solvent, tetrahydrofuran. However, no difference in lifetimes was observed between the 1-vinylnaphthalene/methyl acrylate copolymer 45) and 1-methylnaphthalene. To summarize, the nonradiative decay rate of excited singlet monomer in polymers, koM + k1M, may not be identical to that of a monochromophoric model compound, especially when the polymer contains quenching moieties and the solvent is fluid enough to allow rapid intramolecular quenching to occur. 

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