Reactive functional groups polystyrene

Next to ion exchange resins, the polymeric supports most likely to be used for catalysts are other cross-linked polystyrenes or silica gels. Both are inexpensive, easy to functionalize, and void of other reactive functional groups. Their limitations are the thermal and physical stability of polystyrene and the solubility of silica in alkali. Polystyrene can be derivatized by almost every known reaction of mononuclear aromatic hydrocarbons, and the conditions for those reactions on polymers have been published and reviewed (2D- The surface of silica gel can be covered with a wide range of organic materials by reaction of its hydroxyl groups with silyl esters and chlorosilanes f381. 

The first resins used for sequencing were derived from cross-linked polystyrene beads, primarily because of their availability and chemical stability and ease of introducing reactive functional groups [synthetic methods are discussed in more detail by Laursen (1975b)]. Two polystyrene-based supports have been used, aminopolystyrene (1) (Laursen et a/., 1975) and TETA polystyrene (2) (Horn and Laursen, 1973), both of which are derived from... 

Molecules of a difiinctional monomer such as X-R-Y (where X and Y are mutually reactive functional groups) are polymerized via the elimination of small molecule by-products of XY, a linear condensation polymer with a general formula of X-(-R-)w-Y is formed, whereas when molecules of an olefinic monomer such as H2C=CHR are polymerized, a vinyl polymer with a structure of -[-H2C-CH(R)-]w- is produced. The difunctional and olefinic monomers have been the major monomer sources, and their step and chain polymerization reactions have been the main synthetic routes to the conventional polymers such as polyester and polystyrene, respectively [27]. 

An alternative approach is to incorporate reactive functional groups Into the elastomer, producing an in-situ graft copolymer. This reduces interfacial tension, improving dispersion in processing, and improves the adhesion of the rubber to the thermoplastic In the solid state. A maleated polystyrene/poly(ethylene-co-butylene)/polystyrene triblock copolymer (SEES) has been used successfully to toughen polyamides and polyesters. 

Even in solution the relative rigidity of the polymer support can play a significant role in the reactivity of attached functional groups. Contrasting studies conducted with chloromethylated derivatives of poly(arylene ether sulfone) (Tg 175°C), phenoxy resin (Tg= 65°C) and polystyrene (Tg= 105°C) allow evaluation of chain rigidity effects. We have shown that the rates of quaternization of chloromethylated poly(arylene ether sulfones) and phenoxy resin deviate from the anticipated second order process at... 

Polymeric particles can be constructed from a number of different monomers or copolymer combinations. Some of the more common ones include polystyrene (traditional latex particles), poly(styrene/divinylbenzene) copolymers, poly(styrene/acrylate) copolymers, polymethylmethacrylate (PMMA), poly(hydroxyethyl methacrylate) (pHEMA), poly(vinyltoluene), poly(styrene/butadiene) copolymers, and poly(styrene/vinyltoluene) copolymers. In addition, by mixing into the polymerization reaction combinations of functional monomers, one can create reactive or functional groups on the particle surface for subsequent coupling to affinity ligands. One example of this is a poly(styrene/acrylate) copolymer particle, which creates carboxylate groups within the polymer structure, the number of which is dependent on the ratio of monomers used in the polymerization process. 

Widespread chlorine-containing polymers would include, 1) stable molding material for practical use such as polyvinyl chloride (PVC), polyvinylidene chloride and poly(epichlorohydrin)(PECH) and, 2) reactive polymers capable to introduce additional functional groups via their active chlorines such as chloromethyl polystyrene, poly (3-chloroethyl vinyl-ether) and poly (vinyl chloroacetate). While the latter, especially the chloromethyl polystyrene, has been widely used recently for the synthesis of variety of functional polymers, we should like to talk in this article about the chemical modification of the former, mainly of PVC and PECH, which was developed in our laboratory. 

Even so, a number of chemical agents, including liquids, chemically attack polymers. Reactions that would ordinarily occur with small molecules also occur in polymers, given the same functional groups and reactive sites. Thus benzene, toluene, etc., are readily sulfonated when exposed to sulfuric acid. Likewise polystyrene (PS) is sulfonated when exposed to liquids and gases containing sulfuric acid ... 

The best test for functionality would be in a copolymerization study. A polystyrene with a methacrylate terminal functional group was prepared. A review of relative reactivity ratios indicated that vinyl chloride reacts very rapidly with methacrylates. Therefore, a copolymerization of the polystyrene terminated with a methacrylate functional group in vinyl chloride would be a good test case, and one should observe the disappearance of the MACROMER if the reaction is followed by using GPC analysis. 

The incorporation of pendant Pcs to a polymeric backbone via the grafting of a suitable Pc molecule to a preformed polymer containing appropriate functional groups has been accomplished by Chen and co-workers [163], These authors exploited the axial reactivity of some metalloPcs (namely, In(III)Pcs) to prepare an In(III)Pc-polystyrene copolymer. The most remarkable feature of this material is that cofacial association between the macrocycles is fully prevented. For some applications of the Pcs, such as optical limiting or photodynamic therapy (PDT), aggregation should be avoided because it produces the quenching of the excited-states. 

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