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Turbulent drag reduction (DR) efficiency and mechanical degradation of high-molecular-weight poly(acrylamide) (PAAM) was investigated in a rotating disk apparatus. Drag reduction efficiency of PAAM was measured as a function of rotational speed, polymer concentration, and temperature and then compared with that of poly(ethylene oxide) (PEO). The PAAM exhibited relatively high shear resistance, and its mechanical degradation behavior in a turbulent flow was examined by using both an exponential and a fractional exponential decay equation. [ABSTRACT FROM AUTHOR]

Abstract: In order to improve the processibility of polyaniline (PANI), poly(o-ethoxyaniline) (PEOA) is grafted with ethoxy group on the PANI backbone and synthesized via an emulsion polymerization. The electric conductivity of PEOA is lower than that of PANI due to the interference of ethoxy side group in the electronic conjugation of polymer backbone. However, PEOA has better solubility than PANI in common organic solvents. PEOA/organically modified montmorillonite (OMMT) nanocomposites were thereby prepared via a solvent intercalation method, using an OMMT. The electrical conductivity of PEOA/OMMT nanocomposites was controlled via OMMT contents. The internal structures, electrical properties, and thermal properties of these nanocomposites were examined via wide angle X-ray diffraction (WAXD), transmission electron microscope (TEM), scanning electron microscope (SEM), two probe conductivity measurement, and thermogravimetric analyzer (TGA). The intercalated nanostructures analysed via WAXD and TEM were correlated with the electrical and thermal properties change originated from the nanoscale interaction between OMMT and PEOA. [Copyright &y& Elsevier]