Styrene-methacrylic acid

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. 

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... 

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. 

Figure 1. Olefinic proton resonances of styrene-methacrylic anhydride copolymers containing both uncycttzed methacrylic anhydride units and absorbed monomer (top), and uncyclized methacrylic anhydride units but little absorbed monomer (bottom). This sample was prepared by reacting a styrene-methacrylic acid copolymer with methacrylic anhydride.

The samples were synthesized by the same techniques as those used for the styrene ionomers (12). The protonated styrene-methacrylic acid copolymers were prepared by thermal initiation. The polymerization took place in sealed glass tubes in the bulk at 80 °C after several freeze-thaw cycles. A conversion of 10% was obtained after 19 hr. The polymer was precipitated in methanol and neutralized in a benzene-methanol solution. A similar procedure was used for the deuterated samples except that the unreacted deuterated styrene monomer was evaporated prior to the precipitation. The mixing of the deuterated and protonated styrene copolymers was performed in a benzene solution by stirring for 1 hr. The benzene used as the solvent contained a minimum amount of methanol necessary to dissolve the ionomer (approximately 5-10% for the samples of high ion content). The samples were freeze-dried, then dried further at 60°-80°C under vacuum, and finally compression-molded at Tg - - 30°C. 

Styrene-Methacrylic Acid Copolymers and Their Salts. Two different types of experiments were performed with these copolymers. A possible clustering of the ionic groups was studied with copolymers containing protonated styrene monomers and deuterated methacrylic acid groups. The radius of gyration measurements were studied from mixtures of all deuterated chains in a protonated matrix. 

PVC with ABS and SBS SBS with PS, EVAc and other ingredients HIPS with 12.5 wt% PB SBS SIS with PS and/or IR PS and/or HIPS with PP and SEBS Poly-/)-methylstyrene (F MS) with SBS AN-grafted SEBS with SAN PS with (SB),andSBR SEBS dissolved in styrene, methacrylic acid, and isoprene, then polymerized SEBS-type IPN with carbon black, CB PS with AXBXA or (AXB), (A = styrene,... 

In the case of the epoxy-acrylic graft copolymer, the epoxy is not soluble in the monomer mixture, even as low as a 10% solution. However, the epoxy resin being the majority component acts as the continuous phase. The purpose of the graft epoxy-styrene-methacrylic acid copolymer is to lower the barrier at the interface so that a stable oil-in-oil emulsion is first obtained and upon neutralization with a tertiary amine, dimethyl ethanol amine, a stable oil-in-oil emulsion in water is then obtained. 

Epikote resin ester DX-38 is the reaction product of Epikote DX-20 epoxy resin from Shell Chemicals, in which the epoxy rings are reacted with a styrene/methacrylic acid copolymer, further reaction is carried out with linseed oil fatty acids and finally the product is reacted with maleic anhydride to an acid value of 80 mg KOH/g. 

Exterior durability is enhanced by inclusion of methacrylates and acrylates. Styrene, methacrylic acid, and acrylic acid increase hardness in the coating, while flexibility is conferred by ethyl, butyl, or ethyl-hexyl acrylate. Stain resistance is improved when short-chain (meth)-acrylates are used and acrylics also impart improved resistance to waten Solvent and grease resistance can be improved by copolymerizing acrylonitrile, methacrylamide, and methacrylic acid. 

Styrene-methacrylic acid-alkyl acrylate copolymer... 

Heterogeneous latices were prepared by a two-stage seeded emulsion polymerisation process at 80C using potassium persulphate as initiator and sodium dodecyl sulphate as emulsifier. Styrene-methacrylic acid (MAA) copolymer latices containing varying amounts of MAA were used as seeds. The second stage polymerisation was performed either as a seeded batch process or as a seeded... 

An important example is the preparation of a waterdispersible product by graft polymerization of, for example, styrene-methacrylic acid copolymer onto the aliphatic backbone of a high molecular weight epoxy resin (15). 

The diffusion of cyclohexa-amylose and cyclohepta-amylose (a- and /3-cyclodextrin) has been studied in aqueous solutions of poly(methacrylic acid), sodium poly(styrene sulphonate) and co-poly(styrene-methacrylic acid). A decrease in the diffusion coefficients of the cycloamyloses in these polymer solutions was found to be dependent on the polymer concentration, degree of sulphonation, styrene content, and degree of neutralization. The results were interpreted assuming a 1 1 complex between the cycloamylose and an appropriate residue in the polymer. 

Other related complexes involved poly(ethylene-co-methacrylic acid) with poly(ethyloxazoline) [91] block-copolymers of styrene-methacrylic acid-styrene with pyrene and other aromatic species [92] and complexes of poly(ethylene-co-methacrylic acid) (a commercially available ionomer ) with zinc(ll) salts and l,3-6/5(aminomethyl)cyclohexane [92]. One commercial ionomer (ACR-1560 of Dupont-Mitsui Polychemicals Co., Ltd.) is a copolymer of 94.6mol 7o of ethylene and 5.6mol< o of methacrylic acid. Complexes were prepared with 0.6mol% of a zinc(ll) salt, 0.4mol% l,3-Z)/5(aminomethyl)cyclohexane (BAC), and with 0.6mol o of the zinc salt and 0.4mol% BAC by a melt reaction [94]. 

Ramireddy C, Tuzar Z, Prochazka K, Webber SE, Munk P (1992) Styrene tert-butyl methacrylate and styrene methacrylic-acid block copolymers— synthesis and characterization. Macromolecules 25(9) 2541-2545. doi 10.1021/ma00035a037... 

The reactivity ratios for styrene-aryl methacrylate copolymerizations [79 — 27] differ significantly from those for the styrene-MMA system, so that copolymers derived from the aryl methacrylate copolymers should have different structures (sequence distributions) than conventional styrene-MMA copolymers of equivalent composition. In the system used to prepare styrene-methacrylic acid copolymers [75], the monomer reactivity ratios are comparable to those of the styrene-MMA system, but the stereochemical structure of the conventional copolymers and of those derived from the methacrylic acid copolymers might be expected to differ. In addition, change of the copolymerization solvent can alter the reactivity ratios for the styrene-methacrylic acid system. Finally, styrene-MMA copolymers derived from styrene-methacrylic anhydride copolymers [22] were expected to have especially interesting structures. The tendency of the anhydride units to become incorporated into the copolymers as cyclic units is very high and there is a great tendency for styrene and cyclic anhydride units in the co-... 

---