Polymer Analogue Reaction

Polymers containing azo groups as part of their backbone chain can be used for the synthesis of block copolymers. The azo-containing prepolymers can, for example, be synthesised by condensing small molecule azo compounds with functionalized polymers, by partial decomposition of polymeric azo compounds in the presence of a monomer or via polymer analogue reactions. Block copolymers are obtained when those prepolymers are decomposed in the presence of another monomer. 

Polymer analogue reactions tend to give poor yields of the desired products. Furthermore, where several synthetic steps are required to introduce the azo functions then at least some of all the intermediate products will be present in the final product. Such reactions should be avoided when possible. 

Block Copolymers from Prepolymers Synthesised by Polymer Analogue Reactions... 

The sulfide moiety of PPS can be oxidized to a sulfoxide group. This effects a higher temperature stability. The oxidation has been performed as a polymer analogue reaction using acetic acid and concentrated nitric acid for 24 h at 0-5°C. However, in this process, long reaction times are required, and the attack of the aromatic rings by nitric acid may occur. 

From a chemical point of view, polymers can be classified according to their chemical composition. First, the number of chemically different monomer units, from which the macromolecule is constructed, is considered. A homopolymer is derived from only one species of monomers. This could be the actual starting reactant or a hypothetical monomer if the homopolymer is formed by a modification of another homopolymer (e.g. by polymer analogue reaction). The homopolymer shows only one repeating unit in contrast to a copolymer. A polymer derived from more than one species of monomer is termed copolymer. Copolymers that are obtained by copolymerization of two monomer species are sometimes termed bipolymers, those obtained from three monomers terpolymers, those obtained from four monomers quaterpolymers, etc. [96IUP]... 

PVAC is often used in water emulsions. Copolymers of vinyl acetate (e.g. EVAC) are used in blends to improve the impact strength. PVAC is also the raw material to synthesize other polymers like poly(vinyl alcohol) (polymer analogue reaction). 

PVAL is a watersoluble polymer (nonsoluble in organic solvents). PVAL is prepared by partial or complete hydrolysis (sometimes referred to in this case as saponification) of poly (vinyl acetate). The properties of PVAL depend on the residual content of acetate groups. Polymer analogue reactions of aldehydes with PVAL give poly (vinyl acetals) (with butyraldehyde poly (vinyl butyral) with formaldehyde poly (vinyl formal), see Fig. 2.2.2). The copolymer of PVAL and polyethylene is used as barrier polymer against non-polar solvents. 

Fig. 2.2.2 Poly(vinyl acetals) obtained by polymer analogue reaction of poly(vinyl alcohol) and aldehydes.

Pansier [2] used the bromomethyl analogue, (II), of the Step 2 product in the atom transfer radical polymerization of methyl methacrylate. Lewandowski [3] prepared the tribromomethyl analogue, (111), by reacting with trimethylolpro-pane and then used this reagent to prepare methyl methacrylate star polymers. A reaction profile is provided in Table 3. 

It was also found [13] that triphenylselenonium chloride and its polymer analogue 40 work as highly efficient phase-transfer catalysts even in the presence of a strong base, thus allowing, for example, the phenoxide substitution reaction of 1-bromooctane [13bj. 

The pyrolysis of transition metal carboxylates (in the example of Ni " ) has an essential place due to both (a) the quantitative characteristics of the main stages and (b) the properties of the products obtained. Such metallopolymers can be prepared by two principally different routes by the above-mentioned polymer-analogous reactions, namely, by the interaction of polyacryhc acid with metal salts Ni, (PAA-Ni ), Co " ", Fe " ", and so on (method A), or by radical polymerization of the appropriated monomers—for example, nickel acrylate, [Ni(CH2CHCOO)2] , to give nickel polyacrylate (NiPAcr) (method C). The kinetic peculiarities of metallopolymers thermolysis were compared with the behavior of their low-molecular-weight analogues nickel propionate. 

Cisplatin polymer analogues, made through reaction of tetrachloroplatinate with tetramisole, were tested for their ability to inhibit EMC-D viruses that are responsible for the onset of juvenile diabetes symptoms in ICR Swiss male mice. Briefly, the mice were treated with 1, 5, and 10 mg/kg. Doses of 1 and 5 mg/kg decrease in the severity and incidence of virus-induced diabetes in comparison to untreated mice. In another series of tests, doses of 1 and 10 mg/kg were administered one day prior to injection of the virus, but here there was an increase in the severity and incidence of virus-induced diabetes. Other studies were imdertaken, showing that the polymer showed different activity profiles than the tetramisole (20) itself. 

The very high reactivity of the P—Cl bonds in (4) forms the basis for the now well-known macromolecular substitution method, which has been used to synthesize polymers of types (1) and (2) and some polymers that are hybrids of these and (3). The method involves nucleophilic reactions of (4), and to some extent of its difluoro analogue, with alkoxides or amines. 

This is an ion-exchanger like the sulfonated polymer. The siUca surface can also be functionalized with phosphine complexes when combined with rhodium, these give anchored complexes that behave like their soluble and polymer-supported analogues as catalysts for olefin hydrogenation and other reactions ... 

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