Showing papers on "Divinylbenzene published in 1972"

Intramolecular cyclization of styrene–p‐divinylbenzene copolymers

Abstract: Styrene has been copolymerized at low conversion with minor quantities of p-divinyl-benzene (p-DVB) in (10–15%) solution in toluene and cyclohexane. Under these conditions the molecular weight of the polystyrene formed in the absence of p-DVB was controlled by chain transfer, and the copolymerization coefficients of the styrene and the p-DVB agreed with previous work. Polymer molecular weights were studied as a function of conversion. At very low conversions the number-average (2.2 × 105) and the weight-average (4.4 × 105) molecular weights were unaffected by substituting some of the styrene by p-DVB, but as the reaction continued Mn increased slowly and Mw much faster. On the other hand, even at the lowest conversions the intrinsic viscosity was drastically reduced by the introduction of p-DVB, and the radius of gyration, as measured by light scattering, fell. Infrared studies on the polymer show that the concentration of pendent double bonds in low-conversion copolymers is about half of the doubly substituted phenyl groups. It is concluded that the first polymer chains formed are extensively cyclized with the formation of a relatively large number of small rings.

Heat resistant compositions

Abstract: Heat resistant compositions comprising a blend or mixture of petrolatum and a partially cross-linked polymer such as ptertiary-butylstyrene polymer cross-linked with divinylbenzene, which can also contain a multitude of hollow particles of a synthetic thermoplastic polymer such as a copolymer of styrene and acrylonitrile, are particularly useful as filler materials in cables such as communication cables.

Process for the purification of gases and vapors

Abstract: Impurities are removed from gases or vapors, for example, from air polluted with the impurities to be removed, by contacting the gas or vapor with a macroporous insoluble crosslinked copolymer of styrene and divinylbenzene in the form of beads or granules having a specific surface area of at least 10 m2/g and containing polar and polarizable non-dissociable active groups selected from the class consisting of halogen and nitro- and acetyl-groups.

Mass transport and reaction in sulfonic acid resin catalyst: The dehydration of t-butyl alcohol

Abstract: Kinetics of the dehydration of t-butyl alcohol to isobutylene were measured with a semibatch reactor containing liquid reactant and suspended particles of cation exchange resin catalyst [sulfonated copolymer of styrene and divinylbenzene (DVB)]. Effects on rate were determined for variations in temperature (58 to 76°C.), reactant water mole fraction (0.0005 to 0.10), and catalyst pacticle diameter (77 to 620 μ) and crosslinking (2 to 12% DVB). Nearly anhydrous t-butyl alcohol failed to penetrate the shrunken network of the polymer. Reaction ebgan only on particle peripheries, and product water penetrated the gel network and s welled it to allow penetration of the alcohol. Rate consequently increased to a maximum (about 0.5 moles/min. equivalent of catalyst SO3H groups at 76°C.) and then decreased as water competed with reactant fro catalytic sites. A spherical catalyst particle is modeled as a shrinking cetrol core, free of reactant and water, and a swollen shell in which concent rations are independent of position and time. The model fits reaction rate and separate particle swelling data for 80 μ particles of catalyst containing 12% DVB, but it is increasingly inadequate for larger particles and catalysts of lower DVB contents.

Polymerization of magnetofluids for electron microscopy observations

Abstract: The liquid matrix (heptane, toluene) of several magnetofluids has been substituted by a mixture of styrene and divinylbenzene and then polymerized This procedure allows the direct study of the grain correlations under the influence of a given physical parameter

Process for the discontinuous copolymerization of conjugated dienes containing at most five carbon atoms, and vinylaromatic compounds

Abstract: 1283327 Copolymerizing conjugated dienes and alkenyl aromatic compounds SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ NV 19 April 1971 [16 April 1970] 26920/71 Heading C3P A process for the discontinuous copolymerization of at least one conjugated diene containing at most 5 carbon atoms and at least one alkenyl aromatic compound in a liquid diluent in the presence of an initiator based on lithium comprises (a) preparing a starting mixture of the diluent and a part of the total quantity of each monomer, (b) initiating copolymerization by contacting this mixture with the initiator and (c) keeping the monomer ratio in the reaction mixture constant during the copolymerization by adding the remaining part of each monomer. Specified monomers are butadiene, isoprene and piperylene; and styrene, α-methyl styrene, pmethyl styrene, #-methyl styrene, 1-vinyl naphthalene and 2-vinyl naphthalene. The initiator may be lithium or methyl, isopropyl, butyl, amyl, 2-ethylhexyl or phenyl lithium; ethylene, trimethylene or pentamethylene dilithium; 1,4-dilithiobenzene; 1,5-dilithiobenzene; 1,5-dilithionaphthalene or 1,3,5-trilithium pentane. The diluent may be an aliphatic, cycloaliphatic or aromatic hydrocarbon; and polymerization may be effected in the presence of cross-linking agents, e.g. divinylbenzene, and coupling agents, e.g. silicon tetrachloride, tin tetrachloride, hydrocarbon dihalides, ethyl acetate, ethyl acrylate, phenyl benzoate and diethyl adipate. Examples describe the copolymerization of butadiene and styrene in hexane/ cyclohexane mixtures in the presence of sec. butyl lithium and with the addition of silicon tetrachloride after the monomers.

Porous cross-linked copolymer and ion-exchange resin

Abstract: 1,269,986. Porous cross-linked copolymers and ion-exchange resins. MITSUBISHI CHEMICAL INDUSTRIES Ltd. 10 April, 1969, No. 18496/69. Headings C3C and C3P. A porous, cross-linked copolymer is made by (i) effecting in aqueous suspension copolymerization of a monovinyl or monovinylidene monomer and a polyvinyl or polyvinylidene monomer in the presence of a free radical initiator, an organic solvent and a linear monovinyl or monovinylidene polymer at a temperature above the dissociation temperature of the initiator, and (ii) subsequently extracting with a solvent the linear polymer from the copolymer resulting from the copolymerization, the organic solvent being insoluble in water and capable of dissolving the monomers and of swelling the copolymer, and the linear polymer constituting a homogeneous phase with the monomers and solvent and having an average molecular weight of from 3000 to 300,000. Ion-exchange groups may be introduced into the copolymer either after the extraction of the linear polymer or during the extraction of the linear polymer. In the examples styrene or ethyl acrylate and divinylbenzene were polymerized in an aqueous mixture of polystyrene or polyvinyl acetate, toluene or carbon tetrachloride, benzoyl peroxide and polyvinyl alcohol and the polystyrene or polyvinyl acetate respectively was extracted with a solvent. The copolymer was then made into an ion-exchange resin by treatment with (i) sulphuric acid and then sodium carbonate, (ii) chloromethyl methyl ether and zinc chloride, and then trimethylamine or dimethylamine and sodium hydroxide, or (iii) sodium hydroxide and then hydrochloric acid.

Process for the purification of gases and vapours

Abstract: 1,271,766 Separating gas mixtures by adsorption OCTROOIEN MAATSCHAPPIJ "ACTIVIT" NV 4 June, 1970 [4 June, 1969], No 26998/70 Heading B1L A sorbent of use in the separation of gas and/or vapour mixtures comprises beads of a macroporous insoluble polymer based on monomeric vinyl- or divinyl-aromatic compounds, unsaturated esters, substituted vinyl compounds and derivatives of unsaturated acids or nitriles, the polymer containing polar or polarisable non-disociable halogen, nitro, hydroxyl, ester, aldehyde, ketone, amide, nitrile, acetyl or methylol groups Preferred polymers are a copolymer of styrene with 2-80% by weight of divinylbenzene which contains nitro, chloro or acetyl groups, and a copolymer of methyl methacrylate with glycol dimethacrylate Separations of toluene, methanol, sulphur dioxide, n-butanol, and acetone in each case from air are described

Process for the removal of organic substances from liquids

Abstract: 1,273,911. Adsorbing organic materials from solution. OCTROOIEN MAATSCHAPPIJ ACTIVIT N.V. 4 June, 1970 [4 June, 1969], No. 26999/70. Heading C1C. Organic substances are removed from solution by sorption on a macroporous insoluble polymer of one or more vinyl- or divinylaromatic compounds, the polymer containing nitro, halogen or acetyl groups. The preferred polymer is a copolymer of styrene with 2-80% by weight divinylbenzene which contains nitro groups. Such a polymer is used to remove (a) phenol and sulphuric acid; benzoic acid; methanol; and propionic acid from water, (b) non-sugars from technical sugar solutions, and (c) organic material from drinking water. A similar polymer containing chloro groups instead of nitro groups is used to remove benzoic acid from n-heptane and toluene from water.

Structural parameters of network of macroporous copolymers of styrene and divinyl-benzene determined from their equilibrium swelling in toluene and acetone

Abstract: The swelling of macroporous styrene divinylbenzene copolymers, containing 20, 40, 50, and 70% by weight of divinylbenzene was investigated in toluene and acetone at 25 °C. From the swelling equilibria between the copolymers and the two solvents possessing knownFlory-Huggins interaction parameterχ average isotropic dilatation factor of a dry network\(\left\langle {\bar \alpha ^2 } \right\rangle _0 \) and the concentration of elastically efficient chains in dry gelν* were determined. Crosslinking uniformity in the gel phase of the copolymers was assumed.

Phosphorylated oxidation-reduction ionites

Abstract: Some phosphorylated oxidation-reduction ionites, containing dihydroxybenzene and quinoid groups, were synthesized from the halomethylated copolymers of styrene and divinylbenzene, having ordinary and macroporous structures.