Copolymers of vinyl and vinylidene chlorides with alkyl acrylates

High-molecular-weight copolymers of vinyl chloride and ethyl or butyl acrylate were prepared in high conversion and yield in the presence of boron trifluoride as the acrylate ester complexing agent. When the vinyl chloride monomer is in excess of equimolar amounts, the resulting copolymers are alternating; and when the alkyl acrylates are in excess, acrylate-rich copolymers are obtained. Ethylene–vinyl chloride–ethyl acrylate and propylene–vinyl chloride–ethyl acrylate terpolymers were also obtained with an ethyl acrylate content of 50 mole %. The relative reactivities of propylene, vinyl chloride, and ethylene in these polymerizations were 5.4, 3.8, and 1.0, respectively. Vinylidene chloride–ethyl acrylate copolymers that are nearly alternating and rich in acrylate or in vinylidene chloride have also been prepared. The monomer reactivity ratios for vinylidene chloride and ethyl acrylate in the presence of boron trifluoride are considerably lower than in its absence.     

Pyrolysis of polyacrylonitrile and related polymers—IX: Copolymers of acrylonitrile with vinyl chloride,vinylidene chloride and α-chloroacrylonitrile

In the pyrolysis of copolymers of acrylonitrile with chlorinated comonomers, dehydrochlorination occurs readily and precedes the exothermic oligomerization of the nitrile groups. The comonomer units reduce the intensity of the exotherm reaction but do not effectively block the reaction since it is clear that the oligomerization of nitrile groups remains extensive. Vinylidene chloride and α-chloroacrylonitrile copolymers exhibit excellent thermogravimetric characteristics; it is concluded that crosslinking through the comonomer unit reduces the amount of fragmentation and hence of weight loss from the polymer. The favourable thermoanalytical behaviour suggests that acrylic compositions of this type could be used for carbon fibre processing.     

Graft copolymerizations of gaseous vinyl chloride and vinylidene chloride on preirradiated polypropylene

The graft copolymerizations onto the preirradiated polypropylene fibers of gaseous vinyl chloride and also of gaseous vinylidene chloride were carried out. The fibers were preirradiated with γ-rays from a ⁶⁰Co source at ?78°C. in air to a total dose of 8 X 10⁵ rad, and were thus presumed to contain peroxide radicals which were active in grafting at ordinary temperature. The volume decrease of monomers at constant pressures due to the sorption and the grafting reaction was followed automatically at temperatures ranging from ?10 to 80°C. The net monomer consumption through the grafting process was estimated by subtracting the volume change due to the sorption from the total volume change of monomers. In general, the extent of grafting was lower at the higher grafting temperature and the decrease of the grafting activity of fibers was also accelerated. The grafting was found to increase almost linearly with the logarithm of the reaction time and the logarithm of the radiation of the radiation dose to the fibers. The extent of grafting was also proportional to the vapor pressure of monomer at a given reaction temperature and was supposed to be controlled by the amount of the monomer adsorbed. Raising the irradiation temperature higher than 0°C. brought about a marked decrease in the activity of preirradiated polypropylene. The grafting activity was successfully retained by the polymer for at least a fortnight at ?78°C.     

Copolymers of vinyl chloride with the vinyl esters and acrylates of low molecular weight polyesters of hydroxyacids

Vinyl esters and acrylates of polyesters derived from C₁₀?C₁₈ hydroxyacids have been synthesized and copolymerized with vinyl chloride with the hope of achieving an internally plasticized poly(vinyl chloride). Copolymers containing 10–30% polyester are film-forming materials, and the films cast from THF solutions are generally flexible. A number of these vinyl chloride copolymers with polyesters at approximately 15 and 25% level have been tested for various properties. The internal plasticization is not extensive.     

Thermal degradation of vinylidene chloride/vinyl chloride copolymers in the presence of N-substituted maleimides

As a consequence of their excellent barrier properties vinyl chloride/vinylidene chloride copolymers have long been prominent in the flexible packaging market. While these polymers possess a number of superior characteristics, they tend to undergo thermally- induced degradative dehydrochlorination at process temperatures. This degradation must be controlled to permit processing of the polymers. Three series of N-substituted maleimides (N-alkyl-, N-aralkyl, and N-aryl) have been synthesized, characterized spectroscopically, and evaluated as potential stabilizers for a standard vinyl chloride/vinylidene chloride (85 mass%) copolymer. As surface blends with the polymer, these compounds are ineffective as stabilizers. However, significant stabilization may be achieved by pretreatment of the polymer with N-substituted maleimides. The most effective stabilization of the polymer is afforded by N-aralkyl- or N-arylmaleimides, most notably, N-benzylmaleimide and N-p-methoxyphenylmaleimide.     

Copolymers of vinyl chloride obtained by polymer-analogous reactions of polyvinyl chloride with sodium salts of heteroaromatic H-N acids

By a reaction of PVC with sodium salts of pyrazole and 3,5-dimethylpyrazole we obtained copolymers possessing paramagnetic properties with a concentration of paramagnetic centers 10¹⁷–10¹⁹ spin g^?1 and g-factor of 2.0024-2.0044.     

High stereoselectivity in chelation-controlled intermolecular Heck reactions with aryl chlorides, vinyl chlorides and vinyl triflates

Highly stereoselective chelation-controlled Pd(0)-catalyzed beta-arylations and beta-vinylations of a five-membered chiral, pyrrolidine-based vinyl ether were achieved using aryl- and vinyl chlorides as substrates, yielding quaternary 2-aryl/vinyl-2-methyl cyclopentanones in 89-96% ee under neutral reaction conditions.     

Calculated properties of some possible vinyl chloride metabolites

There is considerable evidence indicating that the carcinogenic action of vinyl chloride involves metabolic conversion to the epoxide (chlorooxirane) as the initial step. In order to learn more about its subsequent behavior, we have computed structures, energies and other properties for two different protonated forms of the epoxide, and also for two possible rearrangement products, chloroacetaldehyde and acetyl chloride. An ab initio SCF -MO procedure (GAUSSIAN 70) was used. Oxygen protonation is found to weaken both C? O bonds, the effect being greater for the bond involving the carbon bearing the chlorine. Chlorine protonation leads to a marked weakening of the C? Cl bond; this suggests a possible loss of HCl, leaving behind a carbonium ion (and possible alkylating agent or rearrangement precursor). Thus, while C? O bond breaking is doubtless an important reaction pathway for chlorooxirane, our results indicate that attention should also be focused upon the C? Cl bond; its rupture may conceivably be a key step in the biological action of vinyl chloride.     

Modification of poly(vinyl alcohol) with acid chlorides and crosslinking with difunctional hardeners

The reaction of acid chlorides with poly(vinyl alcohol) (PVA) leads to vinyl alcohol-vinyl ester copolymers. The esterification by Schotten-Baumann enables degrees of modification to be reached which depend on the chemical structure of the pendant unit introduced. High degrees of modification were obtained in the reaction with water-stable acid chlorides such as benzoyl or cinnamoyl chloride. The copolymers obtained were characterized by spectroscopic techniques, elemental analysis, thermal methods, and viscosity determinations. Since in all cases they were only partially modified, the remaining hydroxyl groups were reacted with difunctional hardeners, Epiclon B-4400, hexamethylene diisocyanate, and tolylene 2,4-diisocyanate, to obtain tridimensional networks. Vinyl alcohol-vinyl benzoate copolymers with different degrees of modification were crosslinked to study how the percentage of remaining hydroxylic groups affects the crosslinking process. The exotherm maximum of the curing process was lower when diisocyanates were used as hardeners and the degree of crosslinking was higher when hexamethylene diisocyanate was used according to the observed increase in T_g values. Whereas the TGA curves of linear polymers only showed one degradation, in crosslinked polymers two degradation steps were detected, suggesting several degradation mechanisms. © 1996 John Wiley & Sons, Inc.     

Copolymers of vinyl fluoride

Vinyl fluoride was polymerized by photochemical initiation in a continuous-flow cylindrical reactor at room temperature and at pressures of up to 30 atm. Copolymers with vinyl acetate were prepared in order to improve the solubility and processability of poly(vinyl fluoride) (PVF). The copolymers were hydrolyzed to the corresponding vinyl alcohol copolymers and yielded hydrophilic films that are strong and flexible only when swollen by water. It was found that on hydrolysis the T_g, T_m, and heat of fusion as well as degree of crystallinity increased. It was suggested that PVF and the copolymers with vinyl alcohol are isomorphous.     

Equilibrium distribution coefficients of some metal chlorides in sodium chloride

Conclusions The method of directed crystallization of the melt was used to determine the distribution coefficients of In Cl₃, SnCl₂, SbCl₃, LaCl₃, IrCl, and AuCl in NaCl in the region of microconcentrations of the contaminant.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, p. 929, April, 1973.     

Fluoroalkylation of vinylidene chloride

Conclusions The conjugated fluoroalkylation of vinylidene chloride was carried out; a series of alkyl halides containing the CCl₂F group was synthesized.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 675–677, March, 1967.     

Studies on molecular weight of poly ((vinylidene chloride)-co-(vinyl chloride)) in the suspension process

Various factors affecting the molecular weight of poly ((vinylidene chloride)-co-(vinyl chloride)) were studied in the paper. Mathematical models correlating intrinsic viscosity of the copolymer with concentrations of 1,2-dichloroethane and initiators, and temperature were proposed and may be used to control the molecular weight of the copolymer.     

Field and laboratory determination of a poly(vinyl/vinylidene chloride) additive in brick mortar

A polymerized vinyl/vinylidene chloride additive, used in brick mortar during the 60s and 70s, is detected at the building site by the field method, which employs a commercially available chloride test strip. The field test results can then be verified by the laboratory methods. In one method, total chlorine in the mortar is determined by an oxygen-bomb method and the additive chloride is determined by difference after water-soluble chlorides have been determined on a separate sample. In the second method, the polymerized additive is extracted directly from the mortar with tetrahydrofuran (THF). The difference in weight before and after extraction of the additive gives the weight of additive in the mortar. Evaporation of the THF from the extract leaves a thin film of the polymer, which gives an infrared "fingerprint" spectrum characteristic of the additive polymer.     

The stabilization of some poly(vinyl chloride) samples

There is discussion of the stabilization of poly(vinyl chloride) by dibutyltindichloride and on the structure/property relationship for the stabilized system.