Vinyl carbazole polymerization using

Applying these methodologies monomers such as isobutylene, vinyl ethers, styrene and styrenic derivatives, oxazolines, N-vinyl carbazole, etc. can be efficiently polymerized leading to well-defined structures. Compared to anionic polymerization cationic polymerization requires less demanding experimental conditions and can be applied at room temperature or higher in many cases, and a wide variety of monomers with pendant functional groups can be used. Despite the recent developments in cationic polymerization the method cannot be used with the same success for the synthesis of well-defined complex copolymeric architectures. 

Other Lewis Acids. Several relatively weak Lewis acids such as zinc halides and mercury halides initiate polymerization of the most reactive monomers such as N-vinyl carbazole, vinyl ethers, and alkoxysty-renes. Many of these acids have poor solubility in hydrocarbons and halo-genated hydrocarbons and are therefore used as acetone or ether solutions. However, such solvents act as nucleophiles, and therefore decrease the acids Lewis acidity. 

Composites of polypyrrole and poly(vinyl chloride) have been prepared by several groups (64-67). Polythiophene-poly(vinyl chloride) composites have also been prepared (68). The electropolymerization of pyrrole on poly(vinyl chloride)-coated electrodes yielded composites with mechanical properties (tensile strength, percent elongation at break, percent elongation at yield) similar to poly(vinyl chloride) (65) but with a conductivity of 5-50 S/cm, which is only slightly inferior to polypyrrole (30-60 S/cm) prepared under similar conditions. In addition, the environmental stability was enhanced. Morphological studies (69) showed that the polypyrrole was not uniformly distributed in the film and had polypyrrole-rich layers next to the electrode. Similarly, poly(vinyl alcohol) (70) poly[(vinylidine chloride)-co-(trifluoroethylene)] (69) and brominated poly(vinyl carbazole) (71) have been used as the matrix polymers. The chemical polymerization of pyrrole in a poly(vinyl alcohol) matrix by ferric chloride and potassium ferricyanide also yielded conducting composites with conductivities of 10 S/cm (72-74). 

Selenide-Based Nonsalt Photoinitiator In more recent years, diphenyldiselenide (DPDS) as nonsalt initiator was used for photosensitized cationic polymerization of /V-vinyl carbazole (NVC) [69]. Diselenide compounds in the presence of aromatic nitriles are well-known photosensitization system for in situ generation of electrophilic... 

Higashimura et al. [28] studied the solid-state polymerization of V-vinyl-carbazole using various catalysts and determined the molecular weight distribution of the polymer by gel permeation chromatography (GPC). The polymers... 

In a heterogeneous system, powdered biosynthesized y-poly(glutamic acid), in the free acid form, has been used to initiate the polymerization of IV-vinyl-carbazole as well as AT-vinyl-2-pyrrolidone. The rate of polymerization in nitrobenzene was greater than in toluene. In the process, there was no significant grafting onto the surface of the y-poly(glutamic acid). It has been proposed that initiation involves proton addition from the surface of the carboxylic acid to the monomer. The propagation proceeds with carboxylate anions on the surface of a counter ion [60]. 

Poly(vinyl carbazole) is produced by polymerization of vinyl carbazole using free-radial initiation or Ziegler-Natta catalysis. 

Each polymerization carried out using monomer (N>vinyl carbazole) 0.097 g at 55 °C in nitrogen atmosphere in benzene medium. 

Solvations of the charged species accelerate the transfer of electrons and the ionizations are enhanced by polar solvents.Charge transfer reaction studies with tetracyanoethylene, an acceptor, and A -vinyl carbazole, a donor, in benzene solution demonstrated that both cation radicals and anion radicals form. This can be used in a subsequent cationic polymerizations ... 

In addition to free radical polymerizations, however, cationic and anionic polymerizations may, depending on solvent used, also be observed. The anodic discharge of acetate ions into the homogeneous phase, for example, produces a free radical polymerization of styrene or acrylonitrile. The anodic discharge of perchlorate or boron tetrafluoride ions, on the other hand, leads to the cationic polymerization of styrene, iV-vinyl carbazole, and isobutyl vinyl ether. In contrast, the cathodic decomposition of tertaalkyl ammonium salts induce acrylonitrile to polymerize anionically. 

Charge transfer has also been used to initiate polymerizations. JV-Vinyl-carbazole (IX) is polymerized to poly(AT-vinylcarbazoIe) in the presence of p-chloranil, tetracyanoethylene and tetracyanoquinondimethide, among others . There is some evidence that complex formation precedes electron... 

Lyoo used a low-temperature initiator, 2,2 -azobis(2,4-dimethyl-valeronitrile), to polymerize N-vinyl carbazole in a heterogeneous solution in a mixture of methyl and t-butyl alcohols [247]. The polymer that formed has the M molecular weights >3 x 10 . The author emphasized that this method provides ultrahigh-molecular-weight polymer and conversions greater than 80%. 

Chain growth addition polymerization based on active carbene (e.g., styrene, vinyl carbazole, isobutylene) is a fast reaction that is most difficult to control since termination by combination or disproportionation is not possible. The initiator for cationic polymerization is a proton from a donor such as water, in the presence of a Lewis acid or sulfuric acid. Polymerization tends to be uncontrollable when undiluted monomers are used, and so these reactions are carried out at low monomer levels, usually in chlorinated... 

Vinyl Ethers and Vinyl Carbazoles.—With few exceptions, most recent kinetic studies of the cationic polymerizations of vinyl ethers and vinyl carbazoles have been conducted with the use of stable carbocation salt initiators, which facilitates analysis of the data. 

Poly(vinyl carbazole) is produced by adiabatic bulk polymerization under nitrogen pressure using azobisisobutyronitrile and di-tert-butyl peroxide as initiators. Heating to 80—90°C causes an onset of polymerization and a rapid increase in temperature. After the maximum temperature has been reached the mass is cooled under pressure. 

TERP, SBRP, and BIRP are routinely carried out without solvent (bulk polymerization), but several solvents have also been used. Polar solvents, such as iV,N-dimethylformamide (DMF) and tetrahydrofuran (THF), were used for the polymerization of N-isopropylacrylamide (NfPAM), acrylonitrile (AN), N-vinyl carbazole (NVC), and acrylic acid (AA). °TERP of NIPAM was also carried out in a DMF/water mixture at 20 °C under condition C7 TERP has been also applied to emulsion polymerization in an aqueous dispersed media (see below). The results dearly indicate the high compatibility of these methods for polar functional groups and solvents. 

Another widely used approach is the in situ polymerization of an intractable polymer such as polypyrrole onto a polymer matrix with some degree of processibil-ity. Bjorklund [30] reported the formation of polypyrrole on methylcellulose and studied the kinetics of the in situ polymerization. Likewise, Gregory et al. [31] reported that conductive fabrics can be prepared by the in situ polymerization of either pyrrole or aniline onto textile substrates. The fabrics obtained by this process maintain the mechanical properties of the substrate and have reasonable surface conductivities. In situ polymerization of acetylene within swollen matrices such as polyethylene, polybutadiene, block copolymers of styrene and diene, and ethylene-propylene-diene terpolymers have also been investigated [32,33]. For example, when a stretched polyacetylene-polybutadiene composite prepared by this approach was iodine-doped, it had a conductivity of around 575 S/cm and excellent environmental stability due to the encapsulation of the ICP [34]. Likewise, composites of polypyrrole and polythiophene prepared by in situ polymerization in matrices such as poly(vinyl chloride), poly(vinyl alcohol), poly(vinylidine chloride-( o-trifluoroethylene), and brominated poly(vi-nyl carbazole) have also been reported. The conductivity of these composites can reach up to 60 S/cm when they are doped with appropriate species [10]. 

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