Styrene-methacrylates

Hepuzer et al. [91] have used the photoinduced homolytical bond scission of ACPB to produce styrene-based MAIs. These compounds were in a second thermally induced polymerization transferred into styrene-methacrylate block copolymers. However, as Scheme 24 implies, benzoin radicals are formed upon photolysis. In the subsequent polymerization they will react with monomer yielding nonazofunctionalized polymer. The relatively high amount of homopolymer has to be separated from the block copolymer formed after the second, thermally induced polymerization step. 

Mori, S., Liquid chromatographic analysis of styrene-methacrylate and styrene-acrylate copolymer, /. Liq. Chromatogr., 13, 3039, 1990. 

The ability to conduct radical reactions without the use of tin reagents is important. Allylic triflones have been used to conduct allylation reactions on a range of substrates (39) as a replacement for allyltributylstannane (Scheme 28). The main limitation was that unactivated or trisubstituted triflones failed to undergo reactions. In other nontin radical methods, arenesulfonyl halides have been used as functional initiators in the CuCl/4,4 -dinonyl-2, 2 -bipyridine-catalysed living atom-transfer polymerization of styrenes, methacrylates, and acrylates.The kinetics of initiation and propagation were examined with a range of substituted arylsulfonyl halides with initiator efficiency measured at 100%. 

Zinc Nitrate. See in Vol 8, N40-L and the following Addnl Refs 1) G.W. Batchelder G.A. Zimmerman, Smokeless Propellant Compositions Containing a Polyester Resin , USP 3653993 (1972) CA 79,77449 (1973) [The inventors claim that Zn nitrate acts as the burning rate catalyst in their propint formulation. Thus, the addn of 0.1% Zn nitrate to a propint contg AN (45), amm dichromate (5%), a polyester, styrene, methacrylate and lecithin increased this parameter from 0.07 to 0.11 indies/ sec] 2) Anon, Fire Protection. . . 7th Edition , NFPA, Boston (1979), 491M-445 [This source reports that Zn nitrate will expld if sprinkled on hot C. Also, that heat, shock and friction sensitive expls are formed when the nitrate is intimately mixed with the following finely divided materials Cu, metal sulfides, organic matter, P and S]... 

The latexes prepared in the group of Ford [68,69] consisted of hydrophobic monomers and a cross-linker, i.e., styrene, methacrylate monomers with various substitutes in the ester moiety, divinylbenzene, and hydrophilic monomers bearing charged groups, viz., styrylmethyl(trimethyl)ammonium and styrylmethyl(tributyl)ammonium cations. The latexes were catalytically active in reactions of decarboxylation of 6-nitrobenzioxazole-3-carboxylate (Scheme 6) and p-nitrophenyl hexanoate hydrolysis (Scheme 7, n = 6). 

Kapui et al. prepared a novel type of polypyrrole films [168]. The film was impregnated by spherical styrene-methacrylic acid block copolymer micelles with a hydrophobic core of 18 nm and a hydrophilic corona of 100 nm. The properties of the micelle-doped polypyrrole films were investigated by cyclic voltammetry and SECM. It was found that the self-assembled block copolymer micelles in polypyrrole behave as polyanions and the charge compensation by cations has been identified during electrochemical switching of the polymer films. 

Keywords porous copolymers, divinylbenzene, styrene, methacrylic monomers, chemically modified silicas, fillers... 

Lecourtier, J. Lafuma, F. Quivoron, C., "Study of Polymer Compatibilization in Solution through Polymer/ Polymer Interactions Ternary Systems Polyethylene oxide)/ Styrene-Methacrylic Acid Copolymers/Solvent," Makromol. Chem., 183,2021 (1982). 

In this work we used polystyrene-based ionomers.-Since there is no crystallinity in this type of ionomer, only the effect of ionic interactions has been observed. Eisenberg et al. reported that for styrene-methacrylic acid ionomers, the position of the high inflection point in the stress relaxation master curve could be approximately predicted from the classical theory of rubber elasticity, assuming that each ion pah-acts as a crosslink up to ca. 6 mol %. Above 6 mol %, the deviation of data points from the calculated curve is very large. For sulfonated polystyrene ionomers, the inflection point in stress relaxation master curves and the rubbery plateau region in dynamic mechanical data seemed to follow the classical rubber theory at low ion content. Therefore, it is generally concluded that polystyrene-based ionomers with low ion content show a crosslinking effect due to multiplet formation. More... 

Plots of the relationship between the styrene content and retention volume for copolymers of styrene-acrylate and styrene-methacrylate with the same ester group lay roughly on the same line. This result indicates that a pair of copolymers with the same ester group and the same styrene content could not be separated (24), For example, copolymers of styrene-methyl acrylate and styrene-MMA with the same styrene content cannot be separated by this technique. In copolymers with the same styrene content, styrene-butyl acrylate and styrene-butyl methacrylate copolymers eluted first from a column, the copolymers of ethyl esters were next, and those of methyl esters eluted last. 

Swift Isco (USA) Monolithic columns Styrene, methacrylate lEX, RP... 

The covalent bonds for dormant species include C—C (eq l),1617 C—S (eqs 2 and 9),131418 C—Se (eq 3),19 C—O (eqs 4 and 5),20 25 C—halogen (eqs 6 and 8),26 28 and C—metal (eq 7),29 all of which can reversibly and homolytically be activated into the growing radical species by physical stimuli such as heat or light or by chemical stimuli such as a metal catalyst or another radical species. Although the controllability, applicability, and reaction conditions depend on which systems are employed, a wide variety of vinyl monomers such as styrenes, methacrylates, acrylates, dienes, and vinyl acetate can be polymerized in a controlled fashion with the use of these or similar systems. Among these, nitroxide-mediated (eq 4)20 24 and metal-catalyzed27 28 systems... 

Figure 9.16. Tan 5 vs. temperature for styrene-methacrylic acid copolymer Ii lied with glass beads of different diameter. [Data from Bergeret A, Alberola N, Polymer, 31, No.13, 1996, 2759-65.]...

Several SANS studies of ionomers have appeared on both deuterium labeled and unlabeled systems(8,12,18-20). The earlier work(14) showed that an ionic peak, similar to that observed by x-rays, could be discerned in some cases, especially when the sample was "decorated" by the incorporation of D20. It was also tentatively concluded(19) that the radius of gyration, R, of the individual chains is not altered when the acid 1s converted to the salt in the case of poly-styrene-methacrylic acid copolymers. Subsequent SANS experiments were performed on sulfonated polystyrene ionomers with up to 8.5% sul-fonation(12). The results of this study indicated that aggregation of the ionic groups is accompanied by considerable chain expansion, which is consistent with the theory of Forsman(ll). 

Relaxation in Styrene-Methacrylic Acid, Sodium Salt Ionomers... 

While ionomers of many types have been made and characterized [1,2,3], there is little work on the overall relaxation mechanisms. For polymers with low ionic concentrations, there is general agreement on the fundamental relaxation step. The stress relaxes by detachment of an ion pair from one cluster and reattachment to another. For the styrene/methacrylic acid Na salt (ST/-MAA-Na) system, there is a secondary plateau in the relaxation modulus which depends on the ionic content and can be described as a rubbery modulus [4], While a rubbery modulus with stress relaxation due to ionic interchange has been invoked earlier, it does not adequately describe the relaxation curves. A different approach is taken here. 

The fundamental equation is given below and its various aspects are then discussed. It was applied to data on styrene/methacrylic acid copolymers, Na salts of Eisenberg and Navratil [4,8]. 

I Kapui, RE Gyurcsanyi, G Nagy, K Toth, M Area, E Area. Investigation of styrene-methacrylic acid block copolymer micelle doped polypyrrole films by scanning electrochemical microscopy. J Phys Chem B 102 9934-9939, 1998. 

Styrene-Methyl Methacrylate Copolymers Derived from Styrene-Methacrylic Anhydride Copolymers... 

Mathematical procedures for calculating structural features of cyclocopolymers and of copolymers derived from them are proposed and are used in studies on the 1H-NMR spectra of styrene-methyl methacrylate copolymers derived from styrene-(methacrylic anhydride) copolymers. Reactivity ratios and cycliza-tion constants for styrene-methacrylic anhydride copolymerization were determined from structural features of the derived styrene-methyl methacrylate copolymers. The amount of uncyclized methacrylic anhydride units present in styrene-methacrylic anhydride copolymers having high styrene contents is considerably less than that predicted by these copolymerization parameters. The methoxy proton resonances of the derived copolymers are more intense in the highest field methoxy proton resonance area than would be expected if such resonance were due only to cosyndiotactic SMS triads. Possible explanations for these discrepancies are proposed. 

Studies on the properties of the derived copolymers can thus be helpful in understanding structure-property relationships of copolymers. Furthermore, since nuclear magnetic resonance can be used to characterize the structures of S-MMA copolymers ( 7,8), structural studies on the derived copolymers can provide information about cyclocopolymerization processes. For these reasons, we have developed a procedure for converting styrene-methacrylic anhydride copolymers into styrene-methyl methacrylate copolymers, have developed methods for calculating structural aspects of the derived S-MMA copolymers and, have investigated the 1H-NMR spectra of S/MMA copolymers derived from styrene-methacrylic anhydride copolymers. 

Several theoretical treatments of cyclocopolymerization have been reported previously (8-11). These relate the compositions of cyclocopolymers to monomer feed concentrations and appropriate rate constant ratios. To our knowledge, procedures for calculating sequence distributions for either cyclocopolymers or for copolymers derived from them have not been developed previously. In this paper we show that procedures for calculating sequence distributions of terpolymers can be used for this purpose. Most previous studies on styrene-methacrylic anhydride copolymerizations (10,12,13) have shown that a high proportion of the methacrylic anhydride units are cyclized in these polymers. Cyclization constants were determined from monomer feed concentrations and the content of uncyclized methacrylic anhydride units in the copolymers. These studies invoked simplifying assumptions that enabled the conventional copolymer equation to be used in determinations of monomer reactivity ratios for this copolymerization system. 

In the present study, this information was obtained primarily from structural studies on S/MMA copolymers derived from styrene-methacrylic anhydride copolymers. A computer oriented procedure was used to analyze the data and this made it unnecessary to employ simplifying assumptions. 

Hydrolysis of styrene-methacrylic anhydride copolymers. One gram samples of the copolymers were suspended in distilled water (150 ml.) and the mixtures were refluxed, with stirring, until solutions were obtained that were stable at room temperature. Copolymers with high styrene contents hydrolyzed slowly and required 108 hr. reaction times. These polymers formed soap-like solutions when completely hydrolyzed. The hydrolyzed polymers were isolated by freeze-drying and were examined by infrared spectroscopy to establish the completeness of hydrolysis. 

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