Styrene-methyl methacrylate alternating copolymer

Peak Notation Assignment of Main Peaks Molecular Weight Retention Index Relative Intensity 

SM methyl 2-methyl-4-phenylpeiit-4-enoate SS 3-butene-1,3-diyldibenzene (styrene dimer) 

SSM methyl 2-methyl-4,6-diphenyl hept-6-enoate SMS methyl 2-phenylethyl-4-phenylpent-4-enoate 

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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. 

The infrared spectograms were obtained on a Beckman IR-10 instrument. Solutions of the styrene-maleic anhydride alternating copolymer and styrene block copolymer were used. A KBr pellet was used for the spectogram of the methyl methacrylate block copolymer. 

Zeng W and Shirota Y (1989) Studies on alternating radical copolymerization analysis of microstructures of styrene-maleic anhydride, styrene-acrylonitrile, and styrene-methyl methacrylate copolymers by fluorescence spectroscopy. Macromolecules 22 4204-8. 

In addition to these irregularities, Winey et al. (1996) have found that in random and alternating copolymers of styrene and methyl methacrylate, the sequence distribution of monomers along the backbone of the polymer strongly affects its miscibility with polystyrene and polymethylmethacrylate homopolymers, even when the overall ratio of styrene/methyl methacrylate in the copolymer chain is held constant. A strictly alternating sequence of monomers in the copolymer was found to be more miscible with the ho-miopolymers than is a copolymer with a random sequence distribution. These results... 

Structure and Properties of Random, Alternating, and Block Copolymers The UV Spectra of Styrene-Methyl Methacrylate Copolymers... 

Complexation with Lewis acids has also been used to alter sequences in copolymerization and prepare alternating copolymers in systems which usually provide very small tendency for alternation like styrene/methyl methacrylate (rs mma 0.5) (130,131). 

With compositions close to the preferred styrene polyester ratio, the overall rate of conversion depends on the reactivity of styrene with maleate and fumarate, the ratio of maleate to fumarate in the polyester, and the reactivity of styrene with itself. Data from the literature on relevant reactivity ratios are conflicting, but the consensus of evidence is that styrene is more reactive with fumarate than with maleate and is more reactive with either than with itself. Similarly, maleate/fumarate is more reactive with styrene than with itself, hence the tendency to form alternating copolymers from styrene and maleate/fumarate unsaturation. Methyl methacrylate is sometimes used as a component in unsaturated polyesters to reduce refractive index and thereby derive aesthetic variations when the polymers are filled with particulates or glass. However, methyl methacrylate could not wholly replace styrene in polyester resins because, unlike styrene, methyl methacrylate is much more reactive with itself than... 

Ihe procedure has been applied to the copolymer series 1-vinyl-naphthalene-methyl methacrylate [17], 1-vinylnaphthalene-methyl acrylate [71], acenaphthylene-methyl methacrylate [26] and styrene-methyl methacrylate [72]. The consistency of the data derived from alternative extrapolations are good as exemplified for the 1-vinylnaphthalene-methyl methacrylate copolymer series in Table (III)... 

Rana D, Mounach H, Halary JL, Monnerie L. Differences in the mechanical behaviour between alternating and random styrene-methyl methacrylate copolymers. J Mater Sci 2005 40(4) 943-953. 

Preparation and Reactions of S-b-MM. As mentioned in the introduction, we were interested in block copolymers of styrene and alkali metal methacrylates with overall molecular weights of about 20,000 and methacrylate contents on the order of 10 mol%. The preparation of such copolymers by the usual anionic techniques is not feasible. An alternative is to prepare block copolymers of styrene and methacrylic esters by sequential anionic polymerization, followed by a post-polymerization reaction to produce the desired block copolymers. The obvious first choice of methacrylic esters is methyl methacrylate. It is inexpensive, readily available, and its block copolymers with styrene are well-known. In fact, Brown and White have reported the preparation and hydrolyses of a series of S-b-MM copolymers of varying MM content using p-toluenesulfonic acid (TsOH) (6). The resulting methacrylic acid copolymers were easily converted to their sodium carboxylates by neutralization with sodium hydroxide. 

Bauer et al. describe the use of a noncontact probe coupled by fiber optics to an FT-Raman system to measure the percentage of dry extractibles and styrene monomer in a styrene/butadiene latex emulsion polymerization reaction using PLS models [201]. Elizalde et al. have examined the use of Raman spectroscopy to monitor the emulsion polymerization of n-butyl acrylate with methyl methacrylate under starved, or low monomer [202], and with high soUds-content [203] conditions. In both cases, models could be built to predict multiple properties, including solids content, residual monomer, and cumulative copolymer composition. Another study compared reaction calorimetry and Raman spectroscopy for monitoring n-butyl acrylate/methyl methacrylate and for vinyl acetate/butyl acrylate, under conditions of normal and instantaneous conversion [204], Both techniques performed well for normal conversion conditions and for overall conversion estimate, but Raman spectroscopy was better at estimating free monomer concentration and instantaneous conversion rate. However, the authors also point out that in certain situations, alternative techniques such as calorimetry can be cheaper, faster, and often easier to maintain accurate models for than Raman spectroscopy, hi a subsequent article, Elizalde et al. found that updating calibration models after... 

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 ... 

In later communications (27, 28) Hirooka reported that in addition to acrylonitrile, other conjugated monomers such as methyl acrylate and methyl methacrylate formed active complexes with organoaluminum halides, and the latter yielded high molecular weight 1 1 alternating copolymers with styrene and ethylene. However, an unconjugated monomer such as vinyl acetate failed to copolymerize with olefins by this technique. 

As shown in Table II, the photoactivated copolymerization of styrene and methyl methacrylate in the presence of AlEt yields equimolar, alternating copolymers when the initial monomer charge contains excess styrene. However, when the comonomers are present in equimolar ratio, the copolymer is rich in methyl methacrylate. ... 

PolyCACN) has a rigid chain structure yet can form excimers with alternate units along the chain (8), or by stacking in a helical conformation. Excimer formation has been reported for alternate copolymers of ACN with styrene (9) and for ACN with maleic anhydride CIO). The situation is different for 2-vinylnaphthalene since alternating copolymers of 2VN with methyl methacrylate or methacrylic acid did not form excimers, yet random copolymers of the same systems showed excimer fluorescence Cll). Only random copolymers of ACN were prepared in this work. 

The nomenclature of random copolymers includes the names of the monomers separated by the interfix -co-. Thus (XXII) is named as poly(styrene-co-methyl methacrylate) or poly(methyl methacrylate-co-styrene), depending on which of the monomers is the major component (if there is one). For alternating copolymers, the interfix -alt- is used, e.g., poly(styrene-a/r-maleic anhydride) (XXIII)... 

The rates of radical-monomer reactions are also dependent on considerations of steric effects. It is observed that most common 1,1-disubstituted monomers — for example, isobutylene, methyl methacrylate and methacrylo-nitrile—react quite readily in both homo- and copolymerizations. On the other hand, 1,2-disubstituted vinyl monomers exhibit a reluctance to ho-mopolymerize, but they do, however, add quite readily to monosubstituted, and perhaps 1,1-disubstituted monomers. A well-known example is styrene (Ml) and maleic anhydride (M2), which copolymerize with r — 0.01 and T2 = 0 at 60°C, forming a 50/50 alternating copolymer over a wide range of monomer feed compositions. This behavior seems to be a consequence of steric hindrance. Calculation of A i2 values for the reactions of various chloroethylenes with radicals of monosubstituted monomers such as styrene, acrylonitrile, and vinyl acetate shows that the effect of a second substituent on monomer reactivity is approximately additive when both substituents are in the 1- or cr-position, but a second substituent when in the 2- or /3-position of the monomer results in a decrease in reactivity due to steric hindrance between it and the polymer radical to which it is adding. 

Chlorine is virtually absent in the copolymer produced in the azobisisobutyronitrile (AIBN) catalyzed copolymerization of styrene and maleic anhydride in the presence of chloroform or carbon tetrachloride (3, 4), or of p-dioxene and maleic anhydride in the presence of acrylonitrile in chloroform (5). This absence indicates that trichloromethyl radicals generated by the reaction of the chlorinated hydrocarbons with the radicals from AIBN are not incorporated into the polymer chain. Similarly, there is little or no cnlorine in the alternating copolymer that is formed in the copolymerization of styrene and methyl methacrylate in the presence of ethylaluminum sesquichloride (EASC) in the presence of chloroform and carbon tetrachloride, and with or without a peroxide initiator (6). 

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