2-vinylpyridine, polymerization

At temperature lower then 50°C, polymerization proceeds very slowly, whereas at 50°C, 4-vinylpyridine and 2-vinylpyridine polymerize very rapidly without any initiator. Using DMF as solvent, the system remains homogeneous through the polymerization time, whereas in acetone precipitates polymer mixture after a few minutes. It is also... 

The study of template polymerization was preceded by examination of quaternary salts polymerization both in aqueous solution and in organic solvents. Examination of 4-vinylpyridine polymerization in water, induced by low molecular weight acids published by Salamone at al shows that in the first step, the following reaction occurs ... 

AlkyUithium compounds are primarily used as initiators for polymerizations of styrenes and dienes (52). These initiators are too reactive for alkyl methacrylates and vinylpyridines. / -ButyUithium [109-72-8] is used commercially to initiate anionic homopolymerization and copolymerization of butadiene, isoprene, and styrene with linear and branched stmctures. Because of the high degree of association (hexameric), -butyIUthium-initiated polymerizations are often effected at elevated temperatures (>50° C) to increase the rate of initiation relative to propagation and thus to obtain polymers with narrower molecular weight distributions (53). Hydrocarbon solutions of this initiator are quite stable at room temperature for extended periods of time the rate of decomposition per month is 0.06% at 20°C (39). 

Synthetic. The main types of elastomeric polymers commercially available in latex form from emulsion polymerization are butadiene—styrene, butadiene—acrylonitrile, and chloroprene (neoprene). There are also a number of specialty latices that contain polymers that are basically variations of the above polymers, eg, those to which a third monomer has been added to provide a polymer that performs a specific function. The most important of these are products that contain either a basic, eg, vinylpyridine, or an acidic monomer, eg, methacrylic acid. These latices are specifically designed for tire cord solutioning, papercoating, and carpet back-sizing. 

In contrast to /3-PCPY, ICPY did not initiate copolymerization of MMA with styrene [39] and AN with styrene [40]. However, it accelerated radical polymerization by increasing the rate of initiation in the former case and decreasing the rate of termination in the latter case. The studies on photocopolymerization of MMA with styrene in the presence of ICPY has also been reported [41], /8-PCPY also initiated radical copolymerization of 4-vinylpyridine with methyl methacrylate [42]. However, the ylide retarded the polymerization of N-vinylpyrrolidone, initiated by AIBN at 60°C in benzene [44]. (See also Table 2.)... 

The structures of these ylide polymers were determined and confirmed by IR and NMR spectra. These were the first stable sulfonium ylide polymers reported in the literature. They are very important for such industrial uses as ion-exchange resins, polymer supports, peptide synthesis, polymeric reagent, and polyelectrolytes. Also in 1977, Hass and Moreau [60] found that when poly(4-vinylpyridine) was quaternized with bromomalonamide, two polymeric quaternary salts resulted. These polyelectrolyte products were subjected to thermal decyana-tion at 7200°C to give isocyanic acid or its isomer, cyanic acid. The addition of base to the solution of polyelectro-lyte in water gave a yellow polymeric ylide. 

A great variety of suitable polymers is accessible by polymerization of vinylic monomers, or by reaction of alcohols or amines with functionalized polymers such as chloromethylat polystyrene or methacryloylchloride. The functionality in the polymer may also a ligand which can bind transition metal complexes. Examples are poly-4-vinylpyridine and triphenylphosphine modified polymers. In all cases of reactively functionalized polymers, the loading with redox active species may also occur after film formation on the electrode surface but it was recognized that such a procedure may lead to inhomogeneous distribution of redox centers in the film... 

In this study, we extend the range of inorganic materials produced from polymeric precursors to include copper composites. Soluble complexes between poly(2-vinylpyridine) (P2VPy) and cupric chloride were prepared in a mixed solvent of 95% methanol 5% water. Pyrolysis of the isolated complexes results in the formation of carbonaceous composites of copper. The decomposition mechanism of the complexes was studied by optical, infrared, x-ray photoelectron and pyrolysis mass spectroscopy as well as thermogravimetric analysis and magnetic susceptibility measurements. 

The surfactant is an important component of this process and acts to stabilize the growing polymeric particles by surface adsorption. Phase separation and the formation of solid particles occur before or after termination of the polymerization process [42]. Polymerization can occur in some systems without the presence of surfactants [40]. Various particulate systems have been prepared by this method, including poly(styrene) [43], poly(vinylpyridine) [44, 45], poly(acrolein) [46, 47], and poly(glutaraldehyde) [48-50],... 

The additional complexity present in block copolymer synthesis is the order of monomer polymerization and/or the requirement in some cases to modify the reactivity of the propagating center during the transition from one block to the next block. This is due to the requirement that the nucleophilicity of the initiating block be equal or greater than the resulting propagating chain end of the second block. Therefore the synthesis of block copolymers by sequential polymerization generally follows the order dienes/styrenics before vinylpyridines before meth(acrylates) before oxiranes/siloxanes. As a consequence, styrene-MMA block copolymers should be prepared by initial polymerization of styrene followed by MMA, while PEO-MMA block copolymers should be prepared by... 

Thomas, T. J. et al., Amer. Inst. Aero. Astron. J., 1976, 14, 1334-1335 Ignition temperatures were determined by DTA for the perchlorate salts of ethylamine, isopropylamine, 4-ethylpyridine, poly(ethyleneimine), poly(propyle-neimine), and poly(2- or 4-vinylpyridine). In contrast to the low ignition temperatures (175-200°C) of the polymeric salts, mixtures of the polymeric bases with ammonium perchlorate decompose only above 300°C. 

Application of amphiphilic block copolymers for nanoparticle formation has been developed by several research groups. R. Schrock et al. prepared nanoparticles in segregated block copolymers in the sohd state [39] A. Eisenberg et al. used ionomer block copolymers and prepared semiconductor particles (PdS, CdS) [40] M. Moller et al. studied gold colloidals in thin films of block copolymers [41]. M. Antonietti et al. studied noble metal nanoparticle stabilized in block copolymer micelles for the purpose of catalysis [36]. Initial studies were focused on the use of poly(styrene)-folock-poly(4-vinylpyridine) (PS-b-P4VP) copolymers prepared by anionic polymerization and its application for noble metal colloid formation and stabilization in solvents such as toluene, THF or cyclohexane (Fig. 6.4) [42]. 

The suitability of ionic liquids (e.g., [EMIM]BF4, [BMIMjPFg, or [OMIM]Tf2N) for free-radical polymerization was explored 249). The homopolymerization of 1-vinyl-2-pyrrolidinone in [BMIMJPFg or that of 4-vinylpyridine in [OMIM]Tf2N resulted in polymers with Mw of 162 500 and 71 500 g/mol, respectively. However, detectable ionic liquid residues were retained in the isolated polymers, even after repeated precipitations from methanol, which is known to dissolve the ionic liquid. The residue may limit the usefulness of ionic liquids as the media for free-radical polymerizations. 

---