Poly peroxydisulfate

The per(poly)fluoroalkylation of olefins by per(poly)fluoroalkyl chlorides, initiated by ammonium peroxydisulfate and sodium formate, is also reported. The reaction proceeds smoothly in polar aprotic solvents. The presence of functional groups like sodium car-boxylate or sulfonate in the polyfluoroalkyl chloride appears to facilitate the reaction. This reaction represents the first example of the reactivity of per(poly)fluoroalkyl chlorides. 

Bissessur and coworkers explored the inclusion of poly(2-ethylaniline) (PEA) and poly(2-propylaniline) (PPA) into GO, in addition to polyaniline [90]. The technique of intercalation differed from previously reported methods. They showed that polyaniUnes can be directly inserted into GO without the preparation of precursor phases. The polymers were first prepared from the monomers by oxidation with ammonium peroxydisulfate in acidic medium. GO, synthesized by using the Hummers method, was dispersed in deionized water with the aid of sonication. Colloidal suspensions of the polymers in NMF were then added to the aqueous GO suspensions. The reaction mixtures were then acidified and heated at 60 °C for 90 min. The intercalated phases were isolated via freezedrying. A similar process was used to intercalate polypyrrole into GO [91]. 

Chemical oxidation polymerization in dilute and semi-dilute solutions of poly(sodium 4-styrenesulfonate) (PSS) was demonstrated for the synthesis of PANI nanocolloids (particle size ca. 2-3 nm) [271]. A similar approach was performed to synthesize PANI nanoparticles using ammonium peroxydisulfate in aqueous medium comprising poly(fi-caprolactone)-PEO-poly(e-caprolactone) amphiphiUc triblock copolymer micelle [272]. Micelle size conspicuously affects the morphology of the PANI nanoparticle, and the PANI nanoparticle size is strongly dependent on PEO molecular weight. The diameter of the nanoparticle increased from 30 nm to lOOnm as the PEO molecular weights decreased. 

Besides vinyl acetate monomer, three other components are neeessary to earry out an emulsion polymerization water, an emulsifier and/or a proteetive eolloid, and a water-soluble initiator. Most commonly, anionic long-chain alkyl sulfonates are used as surfactants in amounts up to 6%. Studies have shown that the rate of polymerization is dependent on the amoimt of emulsifier present, with the rates inereasing as the amoimt of emulsifier is increased up to a certain point and then falling olF as free-radieal ehain transfer to the surfaetant beeomes a serious competing side reaetion [240]. In general, surfactants are used in eombination with a protective colloid. Especially useful as protective colloids are poly(vinyl alcohol), hydroxyethyl cellulose, alkyl vinyl ether-maleic anhydride and styrene-allyl alcohol copolymers, and gum arable. Water-soluble initiators, particularly potassium persulfate, alkali peroxydisulfates, hydrogen peroxide, and various redox systems, are most commonly used. 

Polvfaniline) and oob/(pyrrole) Typical, simple, "in-a-beaker" syntheses of poly(pyrrole) and poly(aniline) may now be illustratively described. Both involve use of a chemical oxidant to generate a radical cation from the monomer, which initiates the polymerization. In the case of poly(pyrrole), 2.5 M of FeCla, the oxidant, is taken in MeOH. Pyrrole (liquid) is then added slowly with stirring and cooling, in a ca. 2 5 pyrrole/FeCla molar ratio. The polymer so obtained is filtered, washed and dried. In the case of poly(aniline), aniline (liquid) is taken either neat or on a substrate, and mixed with oxidant solution, which is typically 0.1 M ammonium peroxydisulfate in 2 M HCl. The solution is cooled in an ice bath to 0 C, while stirring for several hours. The polymer obtained is washed, usually with MeOH, and dried. Variations of even these simple procedures involve use of other solvent media, e.g. acetonitrile/water mixtures, and other oxidants, e.g. CUBF4. 

In situ oxidative polymerization has also been used to prepare/PE/poly-aniline composites. In one approach, microporous PE films were immersed in a solution of aniline hydrochloride and polymerization was started by the introduction of ammonium peroxydisulfate [23]. Similarly, Wan and Yang (1993) obtained PE/polyaniline composites using iron (III) chloride as the oxidant [24]. Solution blending is largely utilized to prepare blends and composites where one or more of the components do not melt easily or are heat susceptible. ICPs Hke polyanifine are difficult to process due to their aromatic structure, interchain hydrogen bonds and effective charge delocahzation in their structures. 

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