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Nanocomposites based on (70/30) blends of natural rubber (NR), styrene-butadiene rubber (SBR), and organoclay (OC) have been prepared successfully via meltmixing process. Effects of the extent of polymers/clay interactions upon the developed microstructure, fatigue life, and dynamic energy loss by the nanocomposites have been investigated. Maleated EPDM (EPDM-g-MAH) and epoxidized NR (ENR50) were employed as compatibilizer. Nanocomposites were characterized by means of X-ray diffractometer (XRD), transmission electron microscope (TEM), scanning electron microscope, atomic force microscopy, root mean square, and dynamic mechanical thermal analysis. EPDM-g-MAH showed more potential in enhancing dispersion of the clay nanolayers and their interaction with rubber phases. More potential for separating and dis-persing the clay nanoplatelets with better interface enhancement was exhibited by EPDM-g-MAH as compatibilizer. This was consistent with higher resistance towards large strain cyclic deformations along with more heat build-up characteristics showed by EPDM-g-MAH based nanocomposites especially at compatibilizer/organoclay ratio of 3. Pronounced non-terminal behavior within low frequency region was also observed for melt storage modulus of this nanocomposite, indicating higher extent of intercalation/ exfoliation microstructure with reinforced interfaces than the nanocomposite generated by ENR50.

The authors report absorption and resorption current measurements on low-loss polypropylene over ranges of 10 mu s to 25 h, 0.5 to 2 MV cm-1, and -175 to 100 degrees C. While the resorption transients always decay hyperbolically, above 20 degrees C the absorption transients develop a conduction tail which is insensitive to contact metal. The current is resolved into volume and surface components, whose variation with time, field and temperature is illustrated. TSD measurements show no significant charge injection from Al contacts, but electron-beam-induced depolarisation experiments disclose heterocharge. Very deep electron traps (depth >or approximately=0.9 eV) and, tentatively, hole traps approximately=0.75 eV deep are identified by TSD on electron-bombarded films. All the observations point to an ionic mechanism, with a threshold related to glass transition, for the conduction tail.

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