Methyl methacrylate with styrene, copolymerization

Copolymerization of methyl methacrylate with styrene in the presence of isotactic poly(methyl methacrylate) has been examined by O Driscoll and Capek. Copolymerization was carried out in acetone at O C and redox system benzoyl peroxide -dimethylaniline was used to initiate the polymerization process. Carrying out the process with various ratios of styrene to methyl methacrylate, it was found that the polymerization rate drops very quickly with the increase in styrene concentration. A very small amount of styrene destroys any template effect that it-poly(methyl methacrylate) exerts on the rate of the polymerization. Assuming, that the reactivity ratios are not changed by the template (ri = i2 = 0.5), the critical length of the sequence of methacrylic units is 10- 20. Complexation occurs only if longer sequences, composed of methacrylic... 

Figure 1. Monomer—copolymer composition relationship for the plasma-initiated copolymerization of methyl methacrylate with styrene. Plasma-initiated polymerization (%) NMR, (x) elemental analysis. Thermal polymerization (O) NMR, (Aj elemental analysis, (—) theoretical curve, tmma = 0.46 =...

Fundamental studies into the copolymerization of tri-alkyl- or triaryltin methyl methacrylate with styrene, MMA, acrylonitrile (AN) and other ccmpounds have been carried out (39, 41). The main principle is that the MCM are distributed randomly along the chain, the alternating... 

Table 22-7. Copolymerization Rates Propagation Rate Constants kp, and Factors for the Free Radical Copolymerization of Methyl Methacrylate with Styrene at 60 C...

Bamford C. Alternating copolymerization in the presence of Lewis acids. In Cowie JMG, ed. Alternating Copolymers. New York Springer US 1985 75—152. Hirai H, Takeuchi K, Komiyama M. Polymerization of coordinated monomers. 19. Kinetic study of the alternating copolymerization of methyl-methacrylate with styrene by boron trichloride. J Polym Sci Part A Polym Chem. 1982 20 159-172. 

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. 

Kennedy 67,77 118) studied the ability of w-styryl-polyisobutene macromonomers to undergo free-radical copolymerization with either styrene or butyl or methyl methacrylate. Here, the macromonomers exhibited a relatively high molecular weight of 9000, and the reaction was stopped after roughly 20% of the comonomer had been converted. The radical reactivity ratios of styrene and methyl methacrylate with respect to macromonomer were found to be equal to 2 and to 0.5, respectively. From these results, Kennedy concluded that in the ra-styrylpolyisobutene/styrene system the reactivity of the macromonomer double bond is reduced whereas with methacrylate as the comonomer the polar effect is the main driving force, yielding reactivities similar to those observed in the classical system styrene/MMA. 

Anionic Copolymerizations. In a significant paper in 1950, Walling, Briggs, Cummings and Mayo (86) investigated the copolymerization behavior of styrene and methyl methacrylate with a number of different initiators. Some of their results are shown in Table 4. 

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]. 

Branched acrylic polymers based upon the copolymerization of acrylates and related monomers with methacrylate macromonomers are particularly useful in waterborne coatings. A macromonomer based upon isobutyl methacrylate, 2-ethylhexyl methacrylate, and 2-hydroxyethyl methacrylate was copolymerized with butyl acrylate, 2-hydroxyethyl acrylate, meth-acrylic acid, methyl methacrylate, and styrene.518 After neutralization with dimethylethanolamine or inorganic bases, the polymer could be cross-linked with melamine resin on a metal surface. These systems may be used for either pigmented layers or clear coats. 

The copolymerization of the polyisobutenylstyrene macromer with methyl methacrylate and styrene gave further interesting new materials (10,11). 

In the end of 1960s, Nikolaev et al.29 and Ito et al.30 independently demonstrated an appreciable effect of the reaction medium on the reactivity ratios in the copolymerization of methyl methacrylate and styrene (Table 19). Ito et al. found that the relative reactivity of methyl methacrylate toward the polystyryl radical is correlated with the transition energies ET for the longest wavelength absorption band for pyridinum TV-phenolbetaine in solvents. They suggested that the polarized structure of methyl methacrylate monomer becomes important in the transition state. Bonta et al.32 also demonstrated that there is an appreciable solvent effect on the reactivity ratio in the styrene-methyl methacrylate copolymerization in non-... 

Methyl methacrylate has been copolymerized with a wide variety of other monomers, such as acrylates, acrylonitrile, styrene, and butadiene. Copolymerization with styrene gives a material with improved melt-flow characteristics. Copolymerization with either butadiene or acrylonitrile, or blending PMMA with SBR, improves impact resistance. Butadiene-methyl methacrylate copolymer has been used in paper and board finishes. 

Copolymerization reactions are affected by solvents. One example that can be cited is an effect of addition of water or glacial acetic acid to a copolymerization mixture of methyl methacrylate with acrylamide in dimethyl sulfoxide or in chloroform. This caused changes in reactivity ratios. Changes in r values that result from changes in solvents in copolymerizations of styrene with methyl methacrylate is another example. The same is true for styrene acrylonitrile copolymeriza-tion. There are also some indications that the temperature may have some effect on the reactivity ratios/ at least in some cases. 

The copolymerization in miniemulsion was not limited to systems for which the monomers were in the dispersed phase. Rather, copolymerization could also be carried out with monomers of opposite polarity - that is, with one comonomer in each phase - in both direct and inverse miniemulsion [26]. Water-soluble, surface active, and oil-soluble initiators were employed to start the polymerizations, as shown in Figure 15.2. Oil-soluble initiators were found to produce a higher yield of copolymers of acrylamide and methyl methacrylate with a low degree of blockiness than did water-soluble or surface-active initiators. In contrast, the surface-active polyethylene glycol (PEG) azo-initiator yielded polymers that were almost free from homopolymers, and with a low degree of blockiness, when acrylamide and styrene were copolymerized. At the interface, monomers that only copolymerize alternately [27] as water-soluble poly(hydroxy vinyl ether)s were also successfully polymerized with oil-soluble maleate esters, to yield polymer nanocapsules. 

Montei and coworkers [240] reported that Nickel complexes [(X,0)NiR(PPh3)] (X = N or P), designed for the polymerization of ethylene, are effective for home- and copolymerization of butyl acrylate, methyl methacrylate, and styrene. Their role as radical initiators was demonstrated from the calculation of the copolymerization reactivity ratios. It was shown that the efficiency of the radical initiation is improved by the addition of PPhs to the nickel complexes as well as by increasing the temperature. The dual role of nickel complex as radical initiators and catalysts was exploited to succeed in the copolymerization of ethylene with butyl acrylate and methyl methacrylate. 

Grafting a second polymer to the NR molecule in the latex stage is one of the many routes to chemically modified NR. An olefinic monomer with unsaturated double bonds such as methyl methacrylate (MMA), styrene and acrylonitrile are important monomers used for such grafting. " For example, MMA monomer is first converted into an emulsion with some suitable emulsifiers and then mixed with NR latex to copolymerize the monomer in a seeded emulsion polymerization process. It is important to ensure the seed latex particles are saturated with the monomer supplied through diffusion from the emulsified monomer droplets. An oil- or water-soluble initiator can be used to start the reaction. With proper control of the system and reaction conditions, the free radical reaction can be made to propagate within the latex particles as far as possible, so that only grafted NR occurs, without the formation of free homopolymer from the monomer. In this way only chemically modified NR... 

Kotani, Y., Kamigaito, M., and Sawamoto, M. (1998). Living random copolymerization of styrene and methyl methacrylate with a Ru(II) complex and synthesis of ABC-type block-random copolymers. Macromolecules, 5/(17) 5582-5587. 

The decay of radicals produced by photo-irradiation of cellulose at room temperature, and the characteristics of photo-irradiated cellulose for the initiation of graft copolymerization with methyl methacrylate have been investigated. The e.s.r. spectra of irradiated samples of untreated, swollen, oximated, or ferric-ion-sensitized celluloses were examined. The decay of radicals was accelerated by solvents (water — methanol > acetone > p-dioxan) and was retarded by methacrylic acid > methyl methacrylate styrene. Graft copolymerization of methyl methacrylate with photo-irradiated cellulose was effectively initiated by water or methanol, but not by either acetone or p-dioxan. It appears that initiation of the graft copolymerization onto pre-irradiated cellulose is promoted by radicals exhibiting a singlet in the e.s.r. spectrum. 

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