Vinyl pyridine polymerization

Spontaneous polymerization of 4-vinyl pyridine in the presence of polyacids was one of the earliest cases of template polymerization studied. Vinyl pyridine polymerizes without an additional initiator in the presence of both low molecular weight acids and polyacids such as poly(acrylic acid), poly(methacrylic acid), polyCvinyl phosphonic acid), or poly(styrene sulfonic acid). The polyacids, in comparison with low molecular weight acids, support much higher initial rates of polymerization and lead to different kinetic equations. The authors suggested that the reaction was initiated by zwitterions. The chain reaction mechanism includes anion addition to activated double bonds of quaternary salt molecules of 4-vinylpyridine, then propagation in the activated center, and termination of the growing center by protonization. The proposed structure of the product, obtained in the case of poly(acrylic acid), used as a template is ... 

Lithium alkyls initiate polymerization of polar monomers like methyl-methacrylate, vinyl pyridine, acrylo-nitrile, etc. However, these reactions are more complex. The desired addition to the C=C bond is accompanied by other processes, e.g., attack on the -COOEt group with the formation of ketones and lithium methoxide, or in vinyl pyridine polymerization by the metalation of the pyridine moiety. 

By cooling the solutions to —80°C almost quantitative conversions to high molecular weight polymers take place [190], Similar conditions yield polystyrene [191]. 4-vinyl pyridine polymerizes in liquid ammonia in the same manner [191]. Initiation results from reduction of the monomer by direct electron transfer at the cathode to form a red-orange vinyl pyridyl radical-anion ... 

As previously described, all microspheres discussed in this chapter were synthesized from AB type diblock copolymers. Precursor block copolymers, poly(styrene-b-4-vinyl pyridine) (P[S-b-4VP]) diblock copolymers, were synthesized using the additional anionic polymerization technique [13]. The basic properties of the block copolymers were determined elsewhere [24,25] and are listed... 

As these block copolymers were synthesized using the anionic polymerization technique, their molecular weight distributions were narrow. The microspheres with narrower size distribution are better for well-ordered self-organization. Actually, all block copolymers synthesized for these works formed poly(4-vinyl pyridine) (P4VP) spheres in the PS matrices with narrow size distributions. 

The poly(styrene-b-isoprene) (P(S-b-IP)) and poly(-styrene-b-2-vinyl pyridine) (P(S-b-2VP)) block copolymers with narrow molecular weight distributions for blending with the microspheres were also synthesized using the additional anionic polymerization technique. The number-average molecular weights (Mns) and PS contents are also shown in Table 1. 

The distinguishing features of the polymerization and copolymerization to these interesting monomers have been described in a number of papers48 49 There are, however, no systematic investigations described in the literature to study the laws governing the reaction of AN copolymerization with quartemary salts of substituted vinyl pyridines. 

Various substituted styrenes have been also polymerized by NMP. These include 1 03-1 07, p-chloromethylstyrene (108), p-halostyrenes, and p-aceloxystyrene. Vinyl pyridines (e.g. 109) are amenable to NMP21 and may be quaternized post-polymerization to provide water-soluble polymers. 

Py ridin-Boran reduziert im Gegensatzzu den iibrigen Amin-Boranen auch Carbonsauren (s.S. 149), Oxime (S.374), Hydrazone (S.371) bzw. Indole (S.87) und steht als Poly-4-vinyl-pyridin-Boran auch in polymerer Form zur Verfiigung1. 

The polymerization of 2-vinyl pyridine initiated by symmetrical Mg compounds... 

Polymer properties, influence of ions, 258 Polymer surface reactions, kinetics, 322-323 Polymer transformation reactions configurational effect, 38 conformational effects, 38 hydrolysis of polyfmethyl methacrylate), 38 neighboring groups, 37-38 quaternization of poly(4-vinyl pyridine), 37-38 Polymerization, siloxanes, 239... 

Hazardous when exposed to oxygen due to peroxide formation and subsequent peroxide initiation of polymerization Styrene Butadiene Tetrafluoroethylene Chlorotrifluoroethylene Vinyl acetylene Vinyl acetate Vinyl chloride Vinyl pyridine Chloroprene... 

Palladium containing homogeneous polymeric catalysts PEO-b-P2VP and PS-b-P4VP were synthesized by the immobilization of appropriate palladium salts into vinyl pyridine cores of PEO-b-P2VP and PS-b-P4VP micelles, respectively, followed by the reduction of the palladium. 

Using copolymer maleic anhydride/styrene instead of poly(maleic anhydride) homopolymer as a template, the authors found that polymerization of 4-vinyl pyridine proceeds also without any initiator, but with lower rate of reaction. 

Investigation of template poly condensation kinetics has only been studied within a very narrow scope. Polymerization of dimethyl tartrate with hexamethylene diamine was found to be enhanced by using as a template poly(vinyl pyrrolidone), poly(2-vinyl pyridine), or polysaccharides and poly(vinyl alcohol), poly(4-vinyl pyridine). In this case, the template can be treated as a catalyst. No information exists on the influence of the template on the order of reaction. The increase in molecular weight of the polymerization product by the template can be induced by a shift of equilibrium or by an increase in the reaction rate. A similar increase in the reaction rate was observed when poly(4-vi-nyl pyridine) was used in the synthesis of poly(terephtalamides) activated by triphenyl phosphite.The authors suggested that a high molecular weight template was involved in the increase of the local concentration of the substrate (terephthalic acid) by adsorption and activation via N-phosphonium salt of poly(4- vinyl pyridine). 

The various kinds of growing species differ not only in their propagation but also in their stereochemical preferences. Professor Hogen-Esch will review this subject in his talk on anionic oligomerization of some vinyl monomer, and mechanisms of anionic, stereospecific polymerization of 2-vinyl pyridine will be discussed by Dr. Fontanille. In this context, the interesting paper of Schuerch et al.(12) deserves attention. Their work clearly reveals the effect of cation solvation upon the mode of monomer s approach to the growing centers. 

On the other hand, the similarity of 2-(2-pyridylJpropene and 2-vinyl pyridine would lead one to expect a similar oligomerization and polymerization stereochemistry, and this is consistent with the formation of single stereoisomers in the oligomerization of both monomers in the presence of Li ion. Crystallographic studies on a single crystal of [14] are presently carried out in order to resolve this question. 

Living Anionic Stereospecific Polymerization of 2-Vinyl pyridine... 

Natta et al. have shown (1,2) that stereospecific polymerization of 2-vinyl pyridine (2VP) can be achieved by using de-solvated Grlgnard reagents as Initiators, In solution In hydrocarbon solvents. Although the essential characteristics were not revealed In this work, there Is no doubt that an anionic mechanism Is operative In such a polymerization. 

The anionic polymerization of 2-vinyl pyridine initiated by benzyl-2 pyridy lmethylmagnesiurn (benzyl picolyl magnesium) in hydrocarbon solvents, leads to highly isotactic polymers. 

This model had been proposed by Fowells et al. (17) on the basis of NMR measurements of partially deuterated polymers prepared in the system THF/Li, and it was applied by Fisher and Szwarc (3o) and Sigwalt and coworkers (31,32)to the polymerization of 2-vinyl pyridine. 

Au NPs have been synthesized in polymeric micelles composed of amphiphilic block copolymers. Poly(styrene)-block-poly(2-vinylpyridine) in toluene has been used as nanocompartments loaded with a defined amount of HAuCl4 and reduced with anhydrous hydrazine. The metal ions can be reduced in such a way that exactly one Au NP is formed in each micelle, where each particle is of equal size between 1 and 15 nm [113]. In another example, the addition of HAuCfi to the triblock copolymer (PS-b-P2VP-b-PEO) (polystyrene-block-poly-2-vinyl pyridine-block-polyethylene oxide) permits the synthesis of Au N Ps using two different routes, such as the reduction of AuC14 by electron irradiation during observation or by addition of an excess of aqueous NaBH4 solution [114]. 

The resins studied (Rohm and Haas and Ionac) were all functionalized, cross-linked, styrene polymers with the exception of poly (4-vinyl-pyridine). Porous, macroreticular resins included the polymeric analogs of N,2V-dimethylbenzylamine (A21 polyDMBA, Rohm and Haas), N,N-dimethylaniline, and l-phenyl-2- (N,2V-dimethylamino) ethane (poly-Alipham), The last two materials were prepared in this laboratory. Nitrogen content of the porous resins was 4.1, 2.5, and 2.6 mequiv/gram, respectively. Poly(4-vinylpyridine) (6.9 mequiv/gram) had a gel-type structure. 

The formation of coagulum is observed in all types of emulsion polymers (i) synthetic rubber latexes such as butadiene-styrene, acrylonitrile-butadiene, and butadiene-styrene-vinyl pyridine copolymers as well as polybutadiene, polychloroprene, and polyisoprene (ii) coatings latexes such as styrene-butadiene, acrylate ester, vinyl acetate, vinyl chloride, and ethylene copolymers (iii) plastisol resins such as polyvinyl chloride (iv) specialty latexes such as polyethylene, polytetrafluoroethylene, and other fluorinated polymers (v) inverse latexes of polyacrylamide and other water-soluble polymers prepared by inverse emulsion polymerization. There are no major latex classes produced by emulsion polymerization that are completely free of coagulum formation during or after polymerization. 

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