Swelling binary solvents

In the resulting binary solvent mixtures of either OSM or TSM micronising step procedures, one apolar component (n-hexane or n-heptane) serves to give high swelling-melting power to the polymer but does not heat under microwave irradiation. The second polar component (ethyl acetate, acetone, and isopropyl alcohol) has... 

The first quantitative theory of the reentrant collapse was developed in Ref. [49], The theory explained the phenomenon of the simple reentrant collapse which was observed in Refs. [14, 41]. A more general theory of swelling and collapse of charged networks in the binary solvent was developed in Ref. [31] and described in Sect. 2.4.1. We have seen that one of the most essential features of the swelling behavior in mixed solvents is a redistribution of solvent molecules within the network giving a different solvent composition in the gel and the external solution. This redistribution is more pronounced for the collapsed gel, because the probability of contacts of the molecules of the solvent with polymer links in the collapsed gel is higher than in the swollen gel. 

J.M O Kane and D.C. Sherrington, Hysteresis-like behavior in the swelling/deswelling of polystyrene cross-linked resins using binary solvent mixtures, Macromolecules, 1990, 23, 5286-5291. 

F or the high accuracy of the analysis of binary solvent composition, a volatile solvent, hexane, was used as a component of SL in most experiments. Following the attainment of equilibrium swelling, the samples were taken out of SL and held in air until the full evaporation of hexane, that was controlled by constant mass of sample. A content of a nonvolatile component of SL in elastomer was determined by the difference between the amount of liq-... 

Determining the solubility parameters of crosslinked polymers uses method based on their maximum swelling in binary solvents of variable composition. The two components of the binary solvent are selected in such a manner that the solubihty parameter of a polymer occupies position intermediate between the parameters of the components. The method is based on the assumption that the maximum swelhng of the polymer occurs when the solubility parameters of mixture and polymer are equal. There should be a maximum on the plot of swelling ratio versus binary mixture composition. 

Poly (vinylchloride)-polypyrrole composite film was prepared by allowing the oxidative polymerization to take place in PVC matrix with diffused pyrrole. The PVC film was immersed in a swelling solution containing pyrrole so that the pyrrole monomer could diffuse into the polymer matrix and then subsequently polymerized in an oxidative solutions containing oxidant in an binary solvent system of similar solubility coefficients with PVC film. Mixture of acetone, n-hexane and pyrrole was chosen as a diffusion solution because it yields highly conductive and transparent composite film with good processability. 

After the immersion of the PVC film into the difusion solution the oxidative polymerization of pyrrole takes place in a 1.0 mole FeCls solution of binary solvent system with acecionitrile and methanol. The oxidation solution requires the capability of swelling PVC for pormoting the deeper penetration of the oxidant into the polymer matrix. For the mixture of acetonitrile and methanol with 1.0 mole FeCls oxidant, the mole fraction of acetonitrile determines the compatibility with the swollen PVC as well as the level of the oxidation potential. The mole ratio of 85/15 of acetonitrile/methanol resulted high electrical conductivity of the composite film with the solvent system of n-hexane, acetone, and pyrrole when polymerized at 0°C. The oxidation potential also varies with the amount of oxidant(FeCl3) as well as the reaction temperature. 

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