Styrene-divinylbenzene network

Styrene-Divinylbenzene Networks. Using ionic polymerization methods, Rietsch et al. (1976) prepared polystyrene (PS) networks with a well-controlled length of elastically active chains and crosslinks of variable functionality. In a given series, the glass transition temperature obeys the classical free volume theory ... 

F.E. Karasz and G. ten Brinke, "The Influence of Thermal Properties on the Glass Transition Temperature in Styrene/Divinylbenzene Network-Diluent Systems." J. Appl. Polym. Sci. 28 23 (1983). 

In a paper with Kanig on styrene-divinylbenzene network copolymers, Ueberreiter sought to illustrate the differences between chemical crosslinks as with DVB and adhesion networks as with the association of "cold spots." Tg becomes increasingly less intense as chemical crosslinks increase in number and there is no evidence of a 7y process. ... 

EUis TS, Karasz FE, ten Brinke G. The influence of thermal properties on the glass transition temperature in styrene/divinylbenzene network-diluent systems. JAppl Polym Sci 1983 28( 1) 23-32. 

Sheu and coworkers [111] produced polysty-rene-polydivinylbenzene latex interpenetrating polymer networks by the seeded emulsion polymerization of styrene-divinylbenzene in the crosslinked uniform polystyrene particles. In this study, a series of uniform polystyrene latexes with different sizes between 0.6 and 8.1... 

The organic resin material is often a styrene divinylbenzene (DVB) copolymer in a network or matrix, to which are attached functional groups such as a sulfonic acid, carboxylic acid, and quaternary ammonium. The nature of these groups determines whether the resin is classified as a strong/weak acid (cation resin) or strong/weak base (anion resin) ion-exchanger. 

Hacroreticular resins are prepared by suspension polymerization of, for example, styrene-divinylbenzene copolymers in the presence of a substance which is a good solvent for the sononer but a poor swelling agent for the polymer [178-180]. Each resin bead is formed from many microbeads joined together during the polymerization process to create a network of holes and 7 channels. This results in greater mechanical stability,... 

The polymeric sorbents are available from several vendors (Hamilton, 3M, and 1ST). In all cases, these sorbents are the styrene-divinylbenzene structure but vary in surface area. Generally speaking the greater the surface area, the greater the capacity of the sorbent for trace organic compounds. Furthermore, the aromatic rings of the matrix network permit electron-donor interactions between the sorbent and ti bonds of the solute, which may further increase analyte-sorbent interactions, which increases the energy of sorption. Thus, the... 

In practice the type of support used most widely is a lightly crosslinked poly(styrene-divinylbenzene) system usually in the form of spherical beads —50-500 pm in diameter produced by suspension polymerisation [51]. Typically the level of the crosslinking comonomer divinylbenzene used is only —0.5-2.0 vol%. This is crucial in terms of structural analysis by NMR, since such lightly crosslinked systems can swell considerably in suitable solvents (up to —15 fold), such that the local environment around a functional group attached to the polymer network can approach closely to that in isotropic solution (see later). 

The "uncrosslinked limit" of many crosslinked polymers can be defined quite easily. For example, polystyrene is the uncrosslinked limit of styrene-divinylbenzene copolymers. On the other hand, the uncrosslinked limit of many other crosslinked polymers cannot be defined unambiguously, and is an idealization. In such cases, there is no unique uncrosslinked limit for a densely crosslinked polymer synthesized from a monomer or monomers with functionalities able to react by several mechanisms. DVS-BCB2 is an example of such a complicated network polymer. However, even for such cases, reasonable choices of uncrosslinked limit can be made. Furthermore, the general form for the dependence of Tg on the crosslink density can be combined with a very small amount of data (such as one or two data points) to give the proper scale for the Tg values and to provide a good estimate for Tg at other crosslink densities. 

For example, the cobalt(II) complex for phthalocyanine tetrasodium sulfonate (PcTs) catalyzes the autoxidation of thiols, such as 2-mercaptoethanol (Eq. 1) [4] and 2,6-di(t-butyl)phenol (Eq. 2) [5]. In the first example the substrate and product were water-soluble whereas the second reaction involved an aqueous suspension. In both cases the activity of the Co(PcTs) was enhanced by binding it to an insoluble polymer, e.g., polyvinylamine [4] or a styrene - divinylbenzene copolymer substituted with quaternary ammonium ions [5]. This enhancement of activity was attributed to inhibition of aggregation of the Co(PcTs) which is known to occur in water, by the polymer network. Hence, in the polymeric form more of the Co(PcTs) will exist in an active monomeric form. In Eq. (2) the polymer-bound Co(PcTs) gave the diphenoquinone (1) with 100% selectivity whereas with soluble Co(PcTs) small amounts of the benzoquinone (2) were also formed. Both reactions involve one-electron oxidations by Co(III) followed by dimerization of the intermediate radical (RS or ArO ). 

The resins [1-11,54-57] are usually bead-like styrene-divinylbenzene (DVB) copolymers, containing 2-8% DVB, which is equivalent to X2-X8 crosslinking of the network. Pearl or ground (meth)acrylate-divinylbenzene or (meth)acrylate-ethyl-ene dimethacrylate copolymers are also used. The most usual products of these types... 

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]. 

Microporous beads are weakly crosslinked resins obtained by suspension polymerisation of styrene and divinylbenzene in the absence of any porogen agent. This process leads to the formation of a homogeneous network evidenced by a glassy and transparent appearance. The most commonly used supports for solid-phase organic synthesis and catalysis are styrene-divinylbenzene copolymers crosslinked with only 1-2% DVB. Many of their derivatives are commercially available [20]. 

Macroporous hypercrosslinked styrene-divinylbenzene copolymers and related networks... 

Shea, K.J. Stoddard, G.J. Sasaki, D.Y. Flourescence probes for the evaluation of diffusion of ionic reagents through network polymers. Chemical quenching of the flourescence emission of the dansyl probe in macroporous styrene-divinylbenzene and styrene-diisopropylbenzene copolymers. Macromolecules 1989, 22, 4303-4308. 

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