Styrene-acrylic acid-divinylbenzene

Porous polymers are prepared by suspension copolymerization of a large excess of monofunctional monomer (e.g. styrene, acrylic acid derivatives or vinylpyrrolidone) with a bifunctional monomer (e.g. divinylbenzene) in a suitable solvent. The cross-linking imparts the required rigidity to the bead polymer structure and, on drying, the solvent evaporates, leaving a porous framework. The choice of reagents, the solvent, catalyst emd the reaction conditions determine bead size and porosity. 

Mole % styrene, acrylic acid (AA) or methacrylic acid (MA), and divinylbenzene (55 % technical grade) in the monomer mixture. Number average particle diameter measured on transmission electron micrographs. 

Styrene can be copolymerized with many monomers. The following monomers can be used along with styrene in the manufacture of food contact materials a-methylsty-rcne, vinyltoluene, divinylbenzene, acrylonitrile, ethyleneoxide, butadiene, fumaric and maleic acid esters of the mono functional saturated aliphatic alcohols C1-C8, acrylic acid ester and methacrylic acid, maleic acid anhydride, methylacrylamide-methylol ether, vinylmethyl ether, vinylisobutyl ether. Styrene and/or a-methylstyrene and/or vinyltoluene should be the main mixture component in every case. 

A bifunctional cation exchange resin carrying strongly acidic (sulfonic) and weakly acidic (carboxylic) groups was introduced in the mid-1960s but was to never merit a sustained commercial viability, and has since been discontinued. Undoubtedly, the acrylic and styrene copolymers with divinylbenzene form the basis of most commercially manufactured cation exchange resins available today. 

Subsequently D Alello developed the polystyrene-hased resin in 1944 (4). Two years later, polystyrene anion-exchange resins made hy chloromethylation and amination of the matrix were produced. Four principal classes of ion-exchange resins were commercially availahle by the 1950s. These are the strong-acid, strong-hase, and weak-hase resins derived from styrene-divinylbenzene copolymers, and the weak-acid resins derived from cross-linked acrylics. To this day, the most widely used ion exchangers are synthetic organic polymer resins based on styrene- or acrylic-acid-type monomers as described by D Alelio in U.S. Patent 2,3666,007. 

Preparation of the coordinating polymers. Polymers containing the carboxyl group can be prepared by radical polymerization and copolymerization, primarily with styrene or divinylbenzene and unsaturated monomers, e.g., acrylic acid, acrylates and methacrylates. 

Definition Diethanolamine salt of a polymer of styrene, divinylbenzene, and two or more monomers of acrylic acid, methacrylic acid or their simple esters... 

Y. Kawabata and coworkers Chemistry Letters (1976), 1213—1214) have reported on the asymmetric hydrogenation brought about by a Rhodium catalyst complexed with a phosphonite derivative of cellulose. Pittman and coworkers (Preprints D/v. Petroleum Chem. 22 (1977), 1196) have attached a (-) DIOP—Rh—catalyst to cross linked styrene-divinylbenzene resins. This polymer displayed activity for the asymmetric hydroformila-tion of styrene, and a study of the dependence of the optical yield from various structural parameters of the polymer has been carried out. J. K. Stille and coworkers ( 7. Am. Chem. Soc. 100 (1978), 264) have prepared a chiral polymer-immobilized (-)DIOP-Rh(I) catalyst which is active in the asymmetric hydrogenation of a-acetamido acrylic acid derivatives with optical yields as high as 86%. Since optical yields were higher in ethanol than in other solvents (e.g. tetrahydrofurane), also a copolymer was prepared, which contained a chiral alcoholic function in addition to the Rh-catalytic function (T. Masuda and J. K. Stille,... 

IGC was also use to elucidate the nature of the interaction of both reactives and products with the surface of heterogeneous catalysts in order to obtain information for understanding the mechanism of the reaction. Xie et al. [31] proposed a mechanism for the partial oxidation of propylene to acrylic acid based on the adsorption parameters of reactive and products on styrene divinylbenzene copolymer (SDB) and Pd supported on SDB. Likewise, Dfaz et al. [53] studied the performance of Fe-ZSM-5 catalysts for benzylation of benzene with benzyl chloride in terms of their chemical and adsorption properties. 

The principal monomers butadiene, styrene, vinyl acetate, (meth)acrylates and acrylonitrile essenhally determine the material properties of films made from the corresponding dispersions the glass transition temperature, the water absorption capacity, the elasticity, etc. Auxiliary monomers, which are only used in a small proportion, usually <5 %, control important properties such as colloid-chemical stabilization (acrylic acid, methacrylic acid, acrylamide, methacrylamide), crosslinking within the particles (difunctional acrylates, divinylbenzene, etc.) or hydrophilic properties (OH-containing monomers, such as hydroxyacrylates). Reactive monomers which still contain a latently reactive group even after incorporation into the polymer, for example glycidylmethacrylate or N-methylol(meth)acrylamide, can form a network between various particles and polymer molecules after film formation. 

Yin et al. [73,74] prepared new microgel star amphiphiles and stndied the compression behavior at the air-water interface. Particles were prepared in a two-step process. First, the gel core was synthesized by copolymerization of styrene and divinylbenzene in diox-ane using benzoylperoxide as initiator. Microgel particles 20 run in diameter were obtained. Second, the gel core was grafted with acrylic or methacryUc acid by free radical polymerization, resulting in amphiphilic polymer particles. These particles were spread from a dimethylformamide/chloroform (1 4) solution at the air-water interface. tt-A cnrves indicated low compressibility above lOmNm and collapse pressnres larger than 40 mNm With increase of the hydrophilic component, the molecnlar area of the polymer and the collapse pressure increased. 

Similarly, cobalt(ll)-pyridine (CoPy) complexes bound to copolymers of styrene and acrylic or methacrylic acid, cross-linked with divinylbenzene, catalyze the autoxidation of tetralin dispersed in water at 50°C and 1 bar.45 The rate of oxidation with the colloidal CoPy catalyst was twice as fast as with homogeneous CoPy and nine times as fast as with cobalt(II) acetate in acetic acid. 

Since the mid-fifties sulfonated resins based on styrene/divinylbenzene copolymers, initially developed as ion exchangers mainly for water treatment, nave also been used as strongly acidic solid catalysts. Witn few exceptions, industrial application in continuous processes is limited to the manufacture of bulk chemicals, sucn as Disphenol A, (meth)acrylates, metnyl ethers of branched olefins (MTBE, TAME) and secondary alcohols (IPA, SBA). 

Most ion-exchange resins based on organic polymers are made by the process of suspension polymerization. The monomers can be neutral as in the case of styrene, divinylbenze, methyl acrylate, and acryonitirle, and the resulting polymer beads are then chemically modihed to introduce the acidic or basic functionality. Styrene-divinylbenzene-based ion exchangers are usually more hydrophobic than their more hydrophilic counterparts. The methacrylate matrix offers a more intermediate polarity and a less hydrophobic surface than styrenic-based materials. 

Metal ion-imprinted microspheres were prepared as follows [14,15]. Seed emulsion was obtained by the polymerisation of styrene, butyl acrylate and methacrylic acid in water. Divinylbenzene, butyl acrylate and water were further added to the polymerisation mixture (seed emulsion) and the emulsion was left for a defined time so that the seed microspheres became swollen. The emulsion was combined with a metal ion solution to achieve complexation between the metal ion and the carboxyl group on the surface. Then the divinylbenzene-containing emulsion was polymerised by the use of y-rays at room temperature. The micro-spheres obtained by centrifugation were washed with a hydrochloric acid solution to remove the metal ion. The microspheres obtained were then dried under vacuum. Non-imprinted microspheres (as a reference) were synthesised similarly, but without a metal ion. 

Porous polymers also are useful for gas analyses and for very polar molecules, such as amines, glycols, and acids. Copolymers of styrene and divinylbenzene and others, such as ethylvinylbenzene-divinylbenzene, cross-linked acrylic ester, vinylpyridine, pyrollidone, and ethylene glycol dimethacrylate, are commercially available. ... 

Comparisons of commonly used XAD resins have been published for the isolation of both fulvic acid (Aiken et al., 1979) and humic acid (Cheng, 1977) from water. These resins differ in pore size, surface area, polymer composition, and polarity (Table 5) (Kunin, 1977). As with anion-exchange resins, hydrophobic styrene-divinylbenzene resins (XAD-1, XAD-2, XAD-4) were found more difficult to elute than hydrophilic acrylic-ester resins (Table 6). This is due to hydrophobic interactions, and possible tt-tt interactions with the aromatic resin matrix of styrene-divinylbenzene resins. In addition, ki-... 

Acrylic-ester resins (XAD-7 and XAD-8) are more hydrophilic, wet more easily, and adsorb more water than styrene-divinylbenzene resins. Kinetics of sorption are much faster, and equilibrium is attained more rapidly. In addition, these resins have higher capacities and are more efficiently eluted than styrene-divinylbenzene resins when fulvic acid is the solute of interest. Because of serious bleed problems of XAD-7 with NaOH (Aiken et al., 1979), XAD-8 is preferred over XAD-7 for the isolation of fulvic acid. 

Both anion and cation hydrocarbon-type exchange membranes (styrene-divinyl-benzene copolymer type) are generally stable in ordinary concentrations of acid solutions (about 40% sulfuric acid, 10% hydrochloric acid, 20% nitric acid, 50% acetic acid) and in alkali solutions such as sodium hydroxide (5%), ammonia (4%), etc.64 However, ion exchange membranes using ethylene glycol dimethacrylate, sulfoethyl methacrylate, and other acrylic and methacrylic esters, are less stable than styrene-divinylbenzene type membranes. 

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