Divinylbenzene macroporous copolymers

A macroporous polystyrene-divinylbenzene copolymer, produced by copolymerizing a mixture of styrene and divinylbenzene, is dissolved in an organic liquid such as t-amyl alcohol or isooctane, which is a solvent for monomers. This solvent is unable to substantially swell the resulting copolymer. Macroporous cation-exchange beads are also produced from these macroporous copolymers (25,26). 

In addition to the silica-based materials mentioned above, modem polymers are widely used for TTA and QTA sample preparation allowing SPE not impaired by undesirable silanol activities. HLB Oasis (Waters) is the tradename for a hydrophilic-lipophilic balance reversed-phase sorbent enabling lipophilic interaction to benzene moieties and hydrophilic interactions to pyrrolidone groups as present in the macroporous copolymer of poly(divinylbenzene-co-iV-vinylpyrrolidone). Elution of analytes is often performed with solvents containing MeOH or ACN. Applying this adsorbent TA such as atropine and scopolamine were extracted from human viscera [15], human serum [97-99], human urine [12] as well as from rat plasma and brain microdialysate [77], Furthermore, this hydrophilic-lipophilic balance phase was also suitable for extraction of the QTA trospium from human and rat plasma [77, 84] and methyl scopolamie from rat plasma [77] (Table 4). 

The growing popularity of reversed phase chromatography in particular has prompted polymer manufacturers to investigate the use of polymeric media for this mode of operation. Macroporous copolymers of styrene and divinylbenzene have similar properties to silica based stationary phases bonded with alkyl chains. However, the absence of leachables and stability at high pH can offer advantages under certain circumstances. High quality, mechanically stable macroporous polymeries are now manufactured at much larger scales than the... 

In 1996, a new hydrophilic-lipopophilic balance (HLB) adsorbent was introduced. Oasis HLB (Waters Corporation, Millford, MA). This macroporous copolymer (poly[divinylbenzene-co-A-vinylpyrrolidone]) exhibits hydrophilic and lipophilic retention characteristics, its major features being the abilities to remain wetted with water and to retain a wide spectrum of polar and nonpolar compounds, among which are OCPs. ... 

Polymeric adsorbents, particularly macroporous styrene—divinylbenzene (DVB) copolymers, are free from these drawbacks of activated carbons. The heat of adsorption onto the polymeric adsorbents is significandy lower and, accordingly, the regeneration of polymers proceeds under much milder conditions. As a rule, the copolymers have no functional groups (apart from those specially introduced) that are capable of catalyzing chemical transformation of an adsorbate. However, in contrast to activated carbons, the specific surface area of most polymeric adsorbents is not very high therefore, their sorption capacity is lower, often making the use of macro-porous polystyrene-type adsorbents unprofitable. This circumstance impelled scientists to develop new types of polymeric materials with an enhanced... 

Hradil et al. [395, 396] prepared a set of composite membranes containing fine particles of conventional macroporous resins or hypercrosslinked polystyrene adsorbing materials in films of poly(2,6-dimethyl-l,4-phenylene oxide) as a binder. Hypercrosslinked resins were either a commercial product, Lewatit EP63 (Bayer AG), or were obtained by crosslinking (i) a macroporous styrene—divinylbenzene (DVB) copolymer with carbon tetrachloride (Hyp-St—DVB) or (ii) a finear polystyrene with monochlorodi-methyl ether. In the latter case the reaction of bridging was conducted in a pretty diluted ethylene dichloride solution at stirring, which resulted in obtaining a particulate (1—5 pm) product. 

The examined polymer-supported catalyst having two different granulations (bead size) A and B was the macroporous cross-linked copolymer of 4-vinylpyridine and 25% (4/1) divinylbenzene-styrene copolymer (commercial product named Reillex 425) [103]. Their average bead diameter (J), skeletal density (p), surface area ( Sbet). porc volume (Vp), and relative swelling ratio (SR) are given in Table 8.2. 

Pd complexes of polymeric diphenylphosphinyl ferrocene are effective catalysts for the hydrosilylation of styrene and 1-hexene by SiHCls. They can be recycled with no loss of activity.Nitrile groups on macroporous copolymers of acrylonitrile/divinylbenzene/ styrene are effective ligands for the immobilization of Rh(I), Pt(II), and Pd(II) complexes, which can be used as hydrosilylation catalysts, with their effectiveness closely related to the morphology of the polymer matrix. Similar transformation was also effected by platinum catalyst immobilized by mercaptan groups over polysiloxane. ... 

Jacobeli H, M. Bartholin, and A. Guyot. Styrene-divinylbenzene copolymers n. Influence of the nature of the diluent on the texture of macroporous copolymers. Anghew. Makromol. Chem. 80 (1979) 31-51. 

A macroporous copolymer of styrene and divinylbenzene is suitable as a stationary phase for reversed-phase separations. Bilic (34) used a column with a 5-p.m polystyrene/divinylbenzene copolymer packing for separation of fluorescent derivatives of ascorbic acid and DHA (see Sect. III.F). Recently, Koshi-... 

P] stands for the copolymer styrene/divinylbenzene, macroporous structure. 

A macroporous polystyrene-divinylbenzene copolymer is produced by a suspension polymerization of a mixture of monomers in the presence of water as a precipitant. This is substantially immiscible with the monomer mixture but is solubilized with a monomer mixture by micelle-forming mechanisms in the presence of the surfactant sodium bis(2-ethylhexylsulfosuccinate) (22). The porosity of percentage void volume of macroporous resin particles is related to percentage weight of the composite (50% precipitant, 50% solvent) in the monomer mixture. 

A research group in Lehigh University has extensively studied the synthesis and characterization of uniform macroporous styrene-divinylbenzene copolymer particles [125,126]. In their studies, uniform porous polymer particles were prepared via seeded emulsion polymerization in which linear polymer (polystyrene seed) or a mixture of linear polymer and solvent were used as inert diluents [125]. The average pore diameter was on the order of 1000 A with pore volumes up to... 

New polymeric solid supports have been devised, which include macroporous styrene-divinylbenzene containing large fixed pores, porous glass beads, insoluble carbohydrate polymers, poly(ethylene oxide), cross-linked derivatives of polyacrylamide resins, and graft copolymers of polystyrene and poly(ethylene oxide). The last two have been the most effective and widely used and have competed well with the original copoly(styrene-divi-nylbenzene) beads. 

Tatsuzawa et aq 36,37,45,59 separat.ed cold drugs and neuroleptics by using a styrene-divinyl benzene-methyl methacrylate copolymer as stationary phase. The best results were obtained with methanol - ammonia (99 1) as mobile phase. The effect of the pH and of the composition of the mobile phase on the separation were discussed. Aramaki et al.70 analyzed a series of alkaloids on a macroporous styrene-divinylbenzene copolymer with alkaline acetonitrile - water mixtures as mobile phase (Fig. 7.10). The columns showed excellent stability, and also under the strong basic conditions used for the analysis of the alkaloids. 

Column, Hitachi Gel 3010 (macroporous styrene-divinylbenzene copolymer), 10 pm (22ox4.6 mm ID), mobile phase, SI acetonitrile - water (3 7) containing 0.02 M tetrabutylammonium hydroxide, S2 acetonitrile - water (6 4) containing 0.02 M tetrabutylammonium hydroxide, S3 acetonitrile - water (6 4) containing 0.02 M ammonia, flow rate 1 ml/min, detection UV 254 nm. 

Figure 2. Fluorescence emission of solvent equilibrated macroporous styrene-divinylbenzene copolymers prepared by suspension polymerization.

The porogen is usually an inert solvent, or mixtures of inert solvent and polymers. The meso- and macropores in the polymer network are the voids once occupied by the porogen. Individual recipes for the preparation of macroporous polymer beads may seem complex in terms of the number of components involved and the required control of the experimental conditions. The technology, however, for their preparation has been developed to such a degree that excellent control over their properties (e.g. particle size, shape, porosity and chemistry) is routinely achieved. The vast majority of current macroporous polymers are based on styrene-divinylbenzene copolymers. Other suitable monomers include acrylates, methacrylates, hydroxyalkylacrylates, vinylpyridines and vinyl acetate. A wide range of products are available for HPLC in particle sizes from 5-20 p,m, pore diameters from about 2-400 nm, and surface areas from about 50-500 m /g [141,144,146-148]. 

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