Styrene and divinylbenzene, copolymers

The formation of macrocomplexes was observed [67] during the mechano-chemical dispersion of A1C13-6H20 with styrene and divinylbenzene copolymers modified by iminodiacetic groups, the co-dispersion of salts with PVC and in... 

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). 

Hydrophobic sorbents including octadecyl, octyl, diphenyl, cyclohexyl, phenyl, butyl, ethyl, methyl, and copolymers of styrene and divinylbenzene can be applied for retaining nonpolar to medium polar analytes. In this list, the styr-ene-divinylbenzene copolymer phases such as PRP-1 and XAD-2 are the most nonpolar phases, while the methyl phase is the least nonpolar one. The analytes are adsorbed onto the hydrophobic materials by means of van der Waals interactions and, to some extent, by hydrophobic bonding or dipole-dipole interactions. 

To a chilled (0°C) suspension of n-propylaminomcthyl poly(styrene)-1 % divinylbenzene copolymer beads (4.32 g, 0.522 mequiv N/ g resin, 2.25 mmol, 200-400 mesh), finely ground potassium carbonate (590 mg, 4.5 mmol), and DMF (50 mL) was added 3-bromo-5-hexyloxybenzenedia-zonium tetrafluoroborate (1.0 g, 2.69 mmol) in portions over 1 h (Scheme 13). After each addition, an aliquot of the DMF supernatant was diluted in diethylamine and analyzed by GC. Once diethyltriazene was detected, the additions were ceased and the suspension was transferred to a fritted filter using DMF and washed sequentially with 120 mL of the following solvents MeOH, water, MeOH, THF, and MeOH. The beads were then dried in vacuo to a constant mass to give 1 -(3-bromo-5-hexyloxyphenyl)-3-propyl-3-(ben-zyl supported) triazene as light yellow material. 

Membranes may be manufactured by mixing powdered ion exchange resin with a solution of binder polymer and pouring the heated mixture under pressure onto a plastic mesh or cloth. The concentration of the ion exchanger is normally 50-70%. They are chiefly copolymers of styrene and divinylbenzene, sulfonated with sulfuric acid for introduction of the cation exchange group. 

Strong Base Anion Exchangers. As in the synthesis of weak base anion exchangers, strong base resins are manufactured from styrenic as well as acrylic copolymers. Those based on copolymers of styrene and divinylbenzene are chloromethylated and then aminated. These reactions are the same as for the styrenic weakbase resins. The essential difference is the amine used for amination. Trimethylamine [75-50-3], N(CH3)3, and A/,A/-dimethylethanolamine [108-01-0], (CH3)2NCH2CH2OH, are most commonly used. Both form quaternary ammonium functional groups similar to (8). 

Currently, the most widely used adsorbents in RPC are silica resins, containing a hydrophobic phase, usually octyl (C8), octyldecyl (C18), methyl (Cl), or phenyl groups. Additionally, new adsorbents based on organic materials such as methacrylate, polystyrene, and copolymers of styrene and divinylbenzene have been developed (Hearn, 1998). 

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 all cases we have a swelling of 10 to 30%, which indicates that even with 55% DVB the desired structure is not realized. To explain these and other facts we proposed the structure given in Figure 12 (42). The reason for its formation is the copolymer ization behavior of DVB. Polymerizing a mixture of styrene and divinylbenzene to... 

From data on copolymers of styrene and divinylbenzene (Bicerano et al. 1996) we constructed a plot of Tg vs. 1/Mcri in order to determine the constant Kcr. Results are shown in Fig. 6.5 and it follows a value of 5.2 x 104 K mol g 1 for Kcri. Of course, the value of term Kcri depends on the system of consideration. 

Recently, the use of chelating exchange resins (e.g., Chelex-100) in preconcentration of trace metals in seawater has become popular [15, 37, 55—61]. Chelex-100 is a copolymer of vinylbenzyliminodiacetic acid, styrene and divinylbenzene, and shows strong chelating activity for various trace metals [12, 55, 56]. 

Ion-exchange separations can also be made by the use of a polymer with exchangeable anions in tliis case, the lanthanide or actinide elements must be initially present as complex ions (11,12). The anion-exchange resins Dowex-1 (a copolymer of styrene and divinylbenzene with quaternary ammonium groups) and Ambedite IRA-400 (a quaternary ammonium polystyrene) have been used successfully. The order of elution is often the reverse of that from cationic-exchange resins. 

Crosslinking affects mainly the a relaxation of polystyrene. Crosslink formation inhibits the molecular motion and, therefore, always causes a net increase in Ta. For example, Ishii et al. [34], working on a copolymer of styrene and 4-ethylstyrene (8mol%), found a shift of 34 K (1Hz) in Ta towards high temperature. The crosslinked polystyrenes of major commercial interest are copolymers of styrene and divinylbenzene. Results of a systematic study of this system have shown that Tg could be represented by the equation [35]... 

Highly hydrophobic sorbents including porous carbon and copolymers of styrene and divinylbenzene (SDB) were widely investigated for environmental applications. The particle-loaded membranes containing modified SDB particles with surface sulfonic acid groups were successfully used for recovering different alcohols, phenols, aldehydes, ketones, or esters from aqueous samples [221]. Carbon-based PLM were also used for isolation of highly polar pesticides from water [222]. 

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. ... 

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