Copolymerizations of methyl methacrylate with styrene

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 =...

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. 

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-... 

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. 

In a more recent study, Charleux et studied the theoretical features of the activation-deactivation equilibrium in nitroxide-mediated copolymerization and applied it to the SGl-mediated copolymerization of methyl methacrylate with a low percentage of styrene (typically in the 4-9 mol.% range). They actually demonstrated that the system exhibited all the characteristics of a living/controlled polymerization, which was explained by the following features (1) the overall concentration of propagating radicals was strongly reduced by the copolymerization effect and the irreversible termination reactions undergone by the MMA/SGf system were hence slowed down (2) isolated styrene subunits were incorporated into the chains and the terminal one promoted the reversible deactivation by the SGI nitroxide and (3) the MMA penultimate unit effect enhanced deactivation of the so-formed styryl-SGf... 

Free radical copolymerization of methyl methacrylate and styrene as well as butyl methacrylate with styrene or isoprene in toluene under microwave irradiation (monomode microwave reactor) has also been carried out (Fellows, 2005). However, no changes in reactivity ratios were observed although more detailed studies were required for the copolymerization of butyl methacrylate and isoprene. The microwave-assisted polymerization procedure accelerated the polymerizations by a factor of 1.7, may be due to an increase in radical flux. It was proposed that the increased radical flux under microwave irradiation is due to rapid orientation of the radicals that are formed from decomposition of the azoisobutyronitrile. This orientation would reduce the number of direct terminations by recombination of the two radical fragments under microwave irradiation and thus, cause a higher radical flux. 

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]. 

Microspheres containing a corona of polyphosphobetaines were obtained by emiflsifier-free emulsion copolymerization of methyl methacrylate and l-methyl-2-methacrylamidoethyl phosphorylcholine [132], MPC [133], or the fumarate monomers of 40 [133], as well as by precipitation polymerization of styrene with MPC macromonomers [134]. Poly-L-lactic acid nanoparti-... 

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... 

Combination of both water-soluble and oil-soluble initiators has also been used in miniemulsion polymerization. Choi et al. ° successfully used both water-soluble potassium persulfate and oil-soluble 2,2 -azobis-(2-methyl butyronitrile) initiators in the miniemulsion polymerization of styrene. Ghazaly et al." used both water-soluble and oil-soluble initiators in the copolymerization of -butyl methacrylate with cross-linking monomers. Variations in the particle morphologies were found between the water-soluble and oil-soluble initiators, depending on the hydrophobicity of the cross-linking monomer. 

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. 

A true random copolymerization of styrene with a polar monomer was reported by Marks and coworkers.The catalyst for the copolymerization, which is generated in situ through Zn reduction of the Ti(IV) precursor derived from the activation of Cp TiMc3 with [Ph3C]+[B(C6Fs)4] , can mediate the copolymerization of methyl methacrylate (MM A) and styrene (1 19 molar feed ratio) at... 

In many cases, azobis(isobutyronitrile) (AIBN) is employed as radical initiator. The polymerization conditions, in particular solvent, depend mainly on both, solubility of the starting sf monomers and choice of comonomer. To give just a few examples, copolymers of dodecafluoroheptyl methacrylate with methacrylic acid could be synthesized in dioxane due to the solubilizing effect of methacrylic acid [66], copolymers of sfMA-H2F8 and sfMA-H2F4 with styrene could be prepared in toluene [35], and copolymerizations of i/methacrylates with butyl acrylate, hydroxy-butyl acrylate, and styrene were performed using tert-butyl peroxyacetate as initiator in methyl amyl ketone [31]. 

Radical copolymerization of an acryl- or methacryl-type PROZO macromonomer (see Scheme 49) with a vinyl monomer of methyl methacrylate (MMA), styrene (St), or acrylamide (AM) produced graft copolymers (Scheme 24). The surface property of the film from the graft copolymer (R=Me) was made hydrophilic due to the character of PMeOZO chain verified by the contact angle measurement. Such behaviors were also observed in the solution of the graft copolymer of PSt-g-PMeOZO via NMR measurement. 

Successful copolymerization of monomer 6 with styrene or methyl methacrylate (MMA), via RAFT or NMP, yielded linear polymers with tunable thiolactone content (4-25%) and controlled molecular weight (M = 6.0-18.0 kDa), although dispersities were relatively high (D 1.5) in the case of PMMA synthesized by NMP (Scheme 11) [49]. 

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. 

In contrast to /3-PCPY, ICPY did not initiate copolymerization of MMA with styrene [39] and AN with styrene [40]. However, it accelerated radical polymerization by increasing the rate of initiation in the former case and decreasing the rate of termination in the latter case. The studies on photocopolymerization of MMA with styrene in the presence of ICPY has also been reported [41], /8-PCPY also initiated radical copolymerization of 4-vinylpyridine with methyl methacrylate [42]. However, the ylide retarded the polymerization of N-vinylpyrrolidone, initiated by AIBN at 60°C in benzene [44]. (See also Table 2.)... 

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