Methyl methacrylate and styrene

AIBN was synthesized using C-labeled reagents and the tagged compound was used to initiate polymerization of methyl methacrylate and styrene. 

MBS polymers are prepared by grafting methyl methacrylate and styrene onto a styrene—butadiene mbber in an emulsion process. The product is a two-phase polymer useful as an impact modifier for rigid poly(vinyl chloride). 

Polymerization and Spinning Solvent. Dimethyl sulfoxide is used as a solvent for the polymerization of acrylonitrile and other vinyl monomers, eg, methyl methacrylate and styrene (82,83). The low incidence of transfer from the growing chain to DMSO leads to high molecular weights. Copolymerization reactions of acrylonitrile with other vinyl monomers are also mn in DMSO. Monomer mixtures of acrylonitrile, styrene, vinyUdene chloride, methallylsulfonic acid, styrenesulfonic acid, etc, are polymerized in DMSO—water (84). In some cases, the fibers are spun from the reaction solutions into DMSO—water baths. 

Notable among the alternative materials are the MBS polymers, in which methyl methacrylate and styrene are grafted on to the polybutadiene backbone. This has resulted in two clear-cut advantages over ABS. The polymers could be made with high clarity and they had better resistance to discolouration in the presence of ultraviolet light. Disadvantages of MBS systems are that they have lower tensile strength and heat deflection temperature under load. 

A prime example of these features can be found in the synthesis of styrene/ (meth)acrylate random copolymers. By controlling the initiator/total monomer ratio, the molecular weight can be accurately controlled for both styrene/methyl methacrylate and styrene/butyl acrylate random copolymers. As can be seen in Figure 2.3 the polydispersity for both systems is essentially 1.10-1.25 over comonomer ratios ranging from 1/9 to 9/1. 

Solomon (3, h, 5.) reported that various clays inhibited or retarded free radical reactions such as thermal and peroxide-initiated polymerization of methyl methacrylate and styrene, peroxide-initiated styrene-unsaturated polyester copolymerization, as well as sulfur vulcanization of styrene-butadiene copolymer rubber. The proposed mechanism for inhibition involved deactivation of free radicals by a one-electron transfer to octahedral aluminum sites on the clay, resulting in a conversion of the free radical, i.e. catalyst radical or chain radical, to a cation which is inactive in these radical initiated and/or propagated reactions. 

Ajayaghosh A, Francis R (1999) A xanthate-derived photoinitiator that recognizes and controls the free radical polymerization pathways of methyl methacrylate and styrene. J Am Chem Soc 121 6599-6606... 

Using the r and tz values from Table 6-2, construct plots showing the initial copolymer composition as a function of the comonomer feed composition for the radical copolymerizations of methyl acrylate-methyl methacrylate and styrene-maleic anhydride. Are these examples of ideal or alternating copolymerization ... 

Indenylidene compounds VIII, K, XXI, XXIII, XXVIIIa and XXVIIIb act as atom transfer radical polymerization catalysts for the polymerization of methyl methacrylate and styrene in high yields and with good control (Table 8.7). The catalytic activity can be dramatically improved by transforming the complexes into cationic species by treatment with AgBp4 [61]. 

The nature of the chlorinated reagent is crucial for promoting the Kharasch addition reaction (Equation 8.11). The results showed that carbon tetrachloride could be added to various olefins in a regioselective way. Under these reaction conditions, no polymerization products were detected. In contrast, when chloroform was used as the halide source the methyl methacrylate and styrene conversions reached only 33% and 40% with the best performing system (VIII), and a significant fraction of polymers was observed [61]. 

Since M2 and M3 are very similar, the S/MA/MM terpolymer might be treated as a copolymer (S/MA), lumping methyl methacrylate and styrene together, and rewriting eq.(5) as... 

Since the late 1960 s a few papers have demonstrated compositional analysis of various polymer systans by Raman spectroscopy. For example, Boerio and Yuann (U) developed a method of analysis for copolymers of glycidyl methacrylate with methyl methacrylate and styrene. Sloane and Bramston-Cook (5) analyzed the terpolymer system poly(methyl methacrylate-co-butadiene-co-styrene). The composition of copolymers of styrene-ethylene dimethacrylate and styrene-divinylbenzene was determined by Stokr et (6). Finally, Water (7) demonstrated that Raman spectroscopy could determine the amount of residual monomer in poly(methyl methacrylate) to the % level. This was subsequently lowered to less than 0.1% (8). In spite of its many advantages, the potential of Raman spectroscopy for the analysis of polymer systems has never been fully exploited. 

The interpolymers obtained with different elastomers vary widely methyl methacrylate and styrene give a soluble product whereas chloroprene, acrylo-... 

Influence of Interpolymer Properties. As stated earlier, the physical and chemical properties of interpolymers markedly influence the reaction rate after the induction period. If the monomer present yields a polymer comparable in viscosity with the initial mixture the rate of scission will not accelebrate. For example, the polymerization rate of chloroprene on mastication with natural rubber does not increase as markedly with conversion (69), see Fig. 19, as with methyl methacrylate and styrene. The reason is the chloroprene-rubber system remained elastic and softer than the original rubber. 

Fig. 5. Copolymerization of methyl methacrylate and styrene in tetrahydrofuran (O) and in N,N-dimethyl formamide ( ). Solid line represents copolymer composition produced by conventional free-radical initiators...

The composition of the grafted side chain copolymer has also been determined by Sakurada (113) and found to be different from the normal copolymer formed with acrylonitrile and butadiene. With styrene the grafted copolymers were found to be richer in acrylonitrile than the normal copolymer. Similar differences were found by Resting (114) with methyl methacrylate and styrene grafted to cotton and by Odian et al. (115) with grafting mixed monomers to Teflon and to polyethylene. It is believed that one monomer may be preferentially sorbed or diffused faster than the other, leading to a different monomer ratio at the actual site of grafting. 

Barnard, D. Ozonolytic degradation of interpolymers of natural rubber with methyl methacrylate and styrene. J. Polymer Sci. 22, 213 (1956). 

Robertson, E. E. Diffusion control in the polymerizations of methyl methacrylate and styrene. Trans. Faraday Soc. 52, 426 (1956). 

Chiou JS, Paul DR (1987) Gas permeation in miscible homopolymer copolymer blends. l.Poly(methyl methacrylate) and styrene acrylonitrile copolymers. J Appl Polym Sci 34 1037-1056... 

Materials. Commercial cotton (Pakistani cotton) cut into 5 mm length and Whatman cellulose powder CF-11 was used as cellulose samples after Soxhlet extraction with alcohol-benzene for 7 h. Wood meal (mainly 40 - 80 mesh) from Makanba (Betula Maximowicziana Regel) was used after washing with cold water. Methyl methacrylate and styrene were purified by the conventional methods. Other reagents used were analytical reagent grade. 

Physical Properties of Blends of Polystyrene with Poly(methyl Methacrylate) and Styrene/ (methyl Methacrylate) Copolymers... 

Figure 1. Room-temperature miscibility diagrams for blends of polystyrene with poly(methyl methacrylate) and styrene/(methyl methacrylate) copolymers. Shaded area is compatible region.

A variety of vinyl monomers, such as methyl methacrylate and styrene, may be used. Complete filling of the cell lumens and other voids (the full-cell process ) is easily accomplished by first subjecting the wood to a partial vacuum (about 0.3 in. of Hg) and then covering it with the monomer and soaking it for 2-6 hr, depending upon the species of wood and its dimensions. Some penetration of the monomer into the cell walls also may be obtained by using a diffusion process, such as a solvent-exchange method. 

It is worth emphasizing in conclusion of this section that a similar analysis of the dynamic system (8.3), (8.4) could be also carried out for terpolymerization, since by now experimental data are available on the dependence of the copolymerization rate on monomer feed composition for terpolymers of methyl methacrylate and styrene with either diethyl maleate [344], N-vinylpyrrolidone [344], or acrylonitrile [346]. 

TABLE 4. Effects of Polymerization of Methyl Methacrylate and Styrene on Their Molar Refractions, Densities, and Refractive Indices... 

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