Toluene swelling polybutadiene

Toluene Swelling. All samples swell substantially when immersed in toluene. It is assumed that toluene, a good solvent for polybutadiene, with a low dielectric constant (e—2.38 at 25°C) is absorbed preferentially in the hydrocarbon polymer phase and excluded from the ionic domains. Swelling is then equivalent to changing the distance between domains. 

The following data were collected on the swelling of polybutadiene vulcanizates of different sulfur contents in toluene at 25° C ... 

Extracting hydrophobic gels prepared by swelling cross-linked polybutadiene with solutions of 4-acylpyrazol-5-one (HL) in toluene, chloroform, and carbon tetrachloride were used for copper extraction studies [192]. The metal distribution curves, close to those obtained in the pure liquid-liquid extraction systems, show that the polymer has no effect on the thermodynamics of the liquid-gel extraction, as shown in Fig. 43. Kinetic studies... 

Nonpolar polymers (polyisoprene, polybutadiene) mix infinitely with alkanes (hexane, oetane, ete.) but do not mix with sueh polar liquids as water and aleohols. Polar polymers (eellulose, polyvinylalcohol, ete.) do not mix with alkanes and readily swell in water. Polymers of the average polarity dissolve only in liquids of average polarity. For example, polystyrene is not dissolved or swollen in water and alkanes but it is dissolved in aromatie hydrocarbons (toluene, benzene, xylene), methyl ethyl ketone and some ethers. Polymethylmethacrylate is not dissolved nor swollen in water nor in alkanes but it is dissolved in dichloroethane. Polychloroprene does not dissolve in water, restrictedly swells in gasoline and dissolves in 1,2-dichloroethane and benzene. Solubility of polyvinylchloride was considered in terms of relationship between the size of a solvent molecule and the distance between polar groups in polymer. ... 

Figure 5.1.2. Dependence of equilibrium swelling of crosslinked elastomer of polyester urethane (1) and polybutadiene nitrile mbber (2) on the volume fraction of acetone in the toluene-acetone mixture. [Adapted, by permission, from V.V. Tereshatov, V.Yu. Senichev,...

The obtained theoretical predictions have been verified in experiments on real elastomers. The elastomers tested in our experiments were amorphous polybutadiene urethanes (PBU) wifli polymer network of different density 0.3 kmol/m (PBU-1), 0.05 kmol/m (PBU-2), 0.2 kmol/m (PBU-3), 0.1 kmol/m (PBU-4). Oligooxypropylene triol - Laprol 373 was used as a crosslinking agent at the curing of prepolymer of oligobutadiene diol. The elastomer specimens were manufactured in the form of disks, 35 mm in diameter and 2 mm thick. The kinetics of specimen swelling was determined in low-molecular liquids toluene, dibutyl sebacate (DBS), dioctyl sebacate (DOS). 

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