The electrical conductivity, thermoelectric power (TEP), and optical properties of organo-soluble polyaniline doped with HCl have been investigated. The electrical conductivity and TEP of the sample increase with increasing temperature. The electrical conductivity and TEP results of the polymer suggest that it is a p-type semiconductor. The fundamental absorption edge in the polymer is formed by the direct allowed transitions, and the optical band gap value was found to be 2.79 eV. The absorption spectra for an acidic solution of the polymer indicate two new absorption bands, which are due to polaron formation. The polaron bands are responsible for the conductivity of the polymer. The TEP results indicate that the conductivity mechanism of the polymer is controlled by the large polaron hopping model.

The retention diagrams of polycaprolactone (PCL) were obtained between 70 and 140°C with solvents such as n-pentane, n-hexane, n-heptane, n-octane, n-nonane, n-decane, isopropyl acetate, isobutyl acetate and tert-butyl acetate by an inverse gas chromatography technique. Some thermodynamical parameters, namely the weight fraction activity coef®cient of the solvent at in®nite dilution, V I 1 , the Flory±Huggins interaction parameter, x I 12 , at in®nite dilution of solvent, the hard-core interaction parameter, x I t , at in®nite dilution of solute, and the effective exchange energy parameters, X 12 in the equation-of-state theory, were determined for these polymer±solvent systems. In addition, the partial molar heat of sorption, DH 1, sorp , the partial molar heat of mixing, DH I 1 of the solvents and the solubility parameter of the polymer, d 2 , were determined for these systems. n-Alkanes were particularly poor solvents but the esters studied were moderately good solvents for PCL. The solubility of the PCL did not change considerably with temperature in all the solvents studied. The values of interaction parameters were close to each other for PCL±ester systems studied. The solubility parameter of PCL, d 2 , was found to be around 10 (cal cm À3 )1/2 at room temperature and decreases linearly with temperature.

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A new polymeric resin with amino sulfonic acid pendant functions has been prepared for the extraction of acidic and basic dyes from water. Beaded polymer supports were prepared by suspension polymerization of vinyl benzyl chloride (0.9 mol) and ethylene glycol dimethacrylate (0.1 mol). The resulting copolymer beads were modified with amino methane sulfonic acid. The dye adsorption capacity of the resin was found as 0.16 g dye/g resin for ramazol black and 0.15 g dye/g resin for crystal violet. The pH depending measurements and dye sorption kinetics of the resin were also investigated.