Characteristics of vinyl chloride

The first triaryknethane dyes were synthesized on a strictiy empirical basis in the late 1850s an example is fuchsine, which was prepared from the reaction of vinyl chloride with aniline. Thek stmctural relationship to triphenylmethane was estabHshed by Otto and Fmil Fischer (5) with the identification of pararosaniline [569-61-9] as 4,4, 4 -triaminotriphenyknethane and the stmctural elucidation of fuchsine. Several different stmctures have been assigned to the triaryknethane dyes (6—8), but none accounts precisely for the observed spectral characteristics. The triaryknethane dyes are therefore generally considered to be resonance hybrids. However, for convenience, usually only one hybrid is indicated, as shown for crystal violet [548-62-9] Cl Basic Violet 3 (1), for which = 589 nm. 

Polymerizations conducted in nonaqueous media in which the polymer is insoluble also display the characteristics of emulsion polymerization. When either vinyl acetate or methyl methacrylate is polymerized in a poor solvent for the polymer, for example, the rate accelerates as the polymerization progresses. This acceleration, which has been called the gel effect,probably is associated with the precipitation of minute droplets of polymer highly swollen with monomer. These droplets may provide polymerization loci in which a single chain radical may be isolated from all others. A similar heterophase polymerization is observed even in the polymerization of the pure monomer in those cases in which the polymer is insoluble in its own monomer. Vinyl chloride, vinylidene chloride, acrylonitrile, and methacryloni-trile polymerize with precipitation of the polymer in a finely divided dispersion as rapidly as it is formed. The reaction rate increases as these polymer particles are generated. In the case of vinyl chloride ... 

Vinyl Chloride/Polyethylene Absorption Isotherms. The absorption isotherms have been determined by adding increasing quantities of vinyl chloride to an aqueous suspension of polyethylene. After saturation of the polyethylene, there is no further increase in the pressure with increasing quantities of vinyl chloride. The principal characteristics of the various polyethylenes examined are shown in Table I. 

Since identical ESR spectra were obtained on U.V. irradiation at liquid nitrogen temperature of PVC, copolymer of vinyl chloride with vinyl bromide and 3-chloropentane it is concluded that this radical is the "Radical I." This radical may play an important role in PVC degradation. To further firmly establish the identity of this radical, theoretical analysis of "Radical I" and computer simulations of ESR spectrum were performed. The polymer radical ESR spectra are very sensitive to the conformation of the chain. The characteristic chain conformation of vinyl syndiotactic sequences in solution has been shown (23) to consist chiefly of trans-trans groups, separated by gauche units . .. (TT)X (GG)i (TT)y (GG)y (TT)Z. .. 

Acrylics, being polar in nature, are compatible with many polar resins. Molecular weight is an important factor in the compatibility of two resins, which should be approximately equal or somewhat lower. By virtue of this compatibility, properties can be improved and desired properties can be achieved for example the flexibility and adhesion characteristic of acrylics can be improved by the addition of vinyl chloride polymers and copolymers. 

Both the time-on-stream and the reactant ratio are important chemical engineering parameters affecting the characteristics of the process. It was found that the increase in the time-on-stream at T = 673K can improve both the conversion of ethane and the yield of ethylene. The total yield of chloroorganic products therewith decreases, but the concentration of vinyl chloride passes through a maximum. We also observed an increase in the yield of deep oxidation products COx (see Table 2). 

Characteristic kinetic and morphological features of vinyl chloride radical polymerization processes were reviewed in89. While developing a mathematical model for the polymerization of this monomer, Canadian90 and Soviet91 investigators concentrated their attention on the heterophase nature of the process. In both cases the dependence of kinetic constants on the viscosity of the medium was disregarded. 

TTomopolymers, copolymers, and terpolymers of vinyl chloride have A been used in the protective and decorative coating fields for nearly three decades. Their resistance to acids, alkalies, weathering, salt water, oil, greases, and food products, coupled with their flexibility, toughness, clarity, ease of pigmentation, flame resistance, and low odor and taste characteristics have contributed to their position in the market place. 

Figure 3 shows the solubility characteristics of the vinyl acetate copolymers in MEK note the improved solubility over the homopolymers of vinyl chloride. Because these copolymers are still significantly less soluble than the metal adhesion terpolymers, one manufacturer has produced a copolymer not based on vinyl acetate (see Figure 3, high solubility copolymers). This copolymer is described in more detail in Figure 13. Copolymers are also available based on vinyl chloride-trifluorochloro-ethylene and vinyl chloride-vinylidene chloride.

Solution polymerization is used almost exclusively for production of copolymers of vinyl chloride and vinyl acetate and terpolymers containing maleates. The vinyl acetate copolymers contain 10-25% acetate, are highly uniform with a narrow molecular weight range, and are valuable mainly because of their unique solubility and film-forming characteristics. They find use as... 

Many companies offer proprietary technology for the manufacture of vinyl chloride. Table 12 is a list of process licensers and a brief description of the characteristics of the technology they offer [21],... 

Copolymers of vinyl chloride with vinyl acetate have lower softening points, easier processing, and better vacuum-forming characteristics than the homopolymers. They are soluble in ketones, esters, and certain chlorinated hydrocarbons, and have generally inferior long-term heat stability. 

The rapid chain transfer to monomer is a most important and characteristic feature of vinyl chloride polymerization, ous mechanisms fiar this reaction have been advanced [23]. A polymer chain does not transfer its radical activity to monomer directly by abstraction of a chlorine or a hydrogen atcnn. The chain transfer mechanism starts widi a head-to-head addition of monomer to the growing radical [24], The resulting radical, species (1), is very unstable and stabilizes itself by rearrangement ... 

A very common copolymer of vinyl chloride is with vinyl acetate. Copolymerization with vinyl acetate improves stability and molding characteristics. The copolymers are also used as fibers and as coatings. Copolymers intended for use in moldings are usually prepared by suspension polymerization. Those intended for coating purposes are prepared by solution, emulsion, and suspension polymerizations. The copolymers used in molding typically contain about 10% poly(vinyl acetate). Copolymers that are prepared for coating purposes can contain from 10-17% poly(vinyl acetate). For coatings, a third comonomer may be included in some resins. This third component may, for instance, be maleic anhydride, in small quantities, like 1%, to improve adhesion to surfaces. 

Diisooctyl azelate (DIOZ) n. C7Hi4(COO C8Hi7)2. a plasticizer for cellulosics resins and polymers and copolymers of vinyl chloride. In vinyls it imparts good low-temperature properties and other characteristics similar to those obtained with dioctyl azelate. 

Emulsifiers. Emulsifiers are very important in the emulsion pol5uneriza-tion of vinyl chloride because they determine not only the latex characteristics but also the properties of the final product (32-34). Moreover, the nature and the... 

The principal characteristics of suspension polymerization have been described in the previous discussion of polystyrene (Section 3.2.3.3). Typically, the suspension polymerization of vinyl chloride is carried out batch-wise in a stirred reactor, jacketed for heating and cooling. The reactor is fitted with a bursting disc (to relieve pressure in case of a runaway reaction) and is also connected to a vacuum line. A typical basic formulation might be as follows ... 

LDPE (Petilen type F.2-12, with melt flow index of 2.0g/10 min and density of 920 kg/m ), PVC (Petvinyl type S 23/29 with K value of 54-58 in cyclohexanone at 25EC and relative viscosity of 1.354-1.417 in the same solvent), vinyl chloride monomer (VCM) and an oligomeric copolymer of vinyl chloride and polyethylene (VCO with 30% Cl) were products of Petkim-Petrochem. Ind. Inc., Turkey. The latter was a side product of VCM, and its characteristics were not disclosed. Carbon tetrachloride used in this study was a reagent grade Merck product. 

The kinetic equivalence of bulk and suspension polymerizations of vinyl chloride has been demonstrated [78]. Thus, the suspension polymerization process may be considered as the polymerization of individual monomer droplets in an inert solvent phase. Naturally, some characteristics peculiar to the suspension process may be superimposed on those of the bulk process. This matter has been nicely summarized by Eliassaf [86, 87]. 

The use of a soluble metal-chelating agent such as tetrasodium ethylenediamine tetraacetate effectively stabilizes an anaerobic formulation against small amounts of metal contamination [173]. The wide variety of appUcations of anaerobic adhesives and sealants is made possible by the modifications which make the viscosity appropriate to the application. An application which requires penetration into close fitting parts should have very low viscosity while a product used with large, loose fitting parts should have a high viscosity. Polymethacrylates, cellulose esters, butadiene-styrene copolymers, acrylonitrile-butadiene-styrene copolymers, polyfvinyl chloride), copolymers of vinyl chloride and vinyl acetate, polyfvinyl acetate), cellulose ethers, polyesters, polyurethanes, and other thermoplastic resins have been used to control the flow characteristics of anaerobic sealants [174]. 

General Characteristics of PVC. Radical polymerization of vinyl chloride monomer favors the formation of syndiotactic sequences and, depending on the temperature of polymerization, the content in rr triads varies from 60% at 50°C to 20% at 70°C. This tendency to syndiotacticity at lower temperature is responsible... 

Gaylord et al. have reported the suspension polymerization of vinyl chloride using the redox system, such as t-butyl peroxyoctoate-SnClz [23,194] and t-butyl peroxyoctoate-stannous carboxylate [192,193]. The polymerization of VCM in the presence of the redox system has several unusual characteristics which can be explained on the basis of the description already made above. 

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