Addition of nanoclays or other nanoparticles into various polymers to produce nanocomposites has been extensively utilized in an attempt to enhance the mechanical, physical, and thermal properties of polymers. While some interesting properties have been demonstrated, the resulting nanocomposites have yet to realize their full potential. Nanoparticles in general, and nanoclays in particular, with their nanometer size, high surface area, and the associated predominance of interfaces in the nanocomposites, can function as structure and morphology directors, for example stabilizing a metastable or conventionally inaccessible polymer phase, or introduce new energy dissipation mechanisms. Thus, what distinguishes nanoparticles from conventional micrometer-size rigid reinforcements is that their role might not be limited to only adding stiffness to the polymer, but also to directing morphology, as well as introducing new energy-dissipation mechanisms leading to enhanced toughness in the nanocomposites. Herein we demonstrate this potential by reporting a remarkable (order of magnitude) increase in toughness with a concurrent increase in stiffness in a poly(vinylidene fluoride) (PVDF) nanocomposite.The kinetics of crystallite growth and the details of crystallite morphology of semicrystalline polymers can be affected by the presence of layered silicates. [1,2] Although some changes in morphology have been described in polymer/nanoparticle hybrids, [3±7] near-total stabilization and control of a crystalline phase, coupled with dramatic enhancements in materials properties, has not yet been reported. PVDF is an important engineering plastic. It is used extensively in the pulp and paper industry due to its resistance to halogens and acids, in nuclear-waste processing for radiation-, and hot-acid applications, and in the chemical processing industry for chemical and high-temperature applications. It is also used in various device applications, due to its unique piezoelectric [8±10] and pyroelectric [11] properties. There are five known crystalline forms or polymorphs of PVDF: a, b, c, d, and e.[12] The a phase is the most common in melt crystallization, and remains the dominant crystalline form versus the b, and c phases. The c phase does not form except at high temperatures and pressures. Earlier reports have shown that the a phase (chain conformationÐtrans-gauche trans-gauche, tgis inactive with respect to piezo-and pyroelectric properties, while the b form (all trans) exhibits the most activity, and is thus the focus for electromechanical and electroacoustic transducer applications. Thus, the b form has great technological utility and there have been numerous attempts to stabilize this phase. For example, the b form of the PVDF has been obtained by careful crystallization from solution, [13] by melt crystallization at high pressure, by application of a strong electric field, [14] by molecular epitaxy, [15] and by preparing a carbon-coated, highly oriented ultrathin film.[16] Earlier reports have indicated the possibility...

Olive mill waste (OMW) management has been a problem in the Mediterranean basin for thousands of years. The solid exiting the extraction process contains polyphenols that are beneficial to humans and phytotoxic to plants. We propose an integrated biorefinery concept for OMW management: supercritical fluid extraction to recover polyphenols, followed by pyrolysis of the solid to produce bio-renewable fuels, and finally activation of the biochar to yield high surface area adsorbents for heavy-metals removal from water. This work details the impact of supercritical fluid extraction on biochars that are subsequently activated with CO 2 and KOH. Specific surface areas of the OMW biochars were over 2300 m 2 /g. Though supercritical fluid extraction increased the surface areas of raw, pyrolyzed, and KOH-activated OMW, the effect was reversed for biochars activated using high-temperature CO 2 . FTIR analysis showed that the supercritical fluid extraction significantly altered the surface functional groups of raw waste, but that activation conditions dictate surface characteristics of the resulting activated biochar. High-temperature KOH and low-temperature CO 2 activation yielded activated biochars with the highest relative amounts of oxygenated functional groups. Activated samples demonstrate adsorption capacities upward of 400 mg of metal (Cd, Co, Cu, and Zn) per gram of sample and follow pseudo-second-order kinetics, with 75% adsorption capacity reached in less than 5 min. This integrated biorefinery concept simultaneously mitigates the environmental impacts of OMW disposal, yields high-value biopharmaceuticals and renewable energy, and provides a sorbent material for water treatment.

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the second cannot be ignored, expecially for samples heated in air. Either POFs or HF would explain the acidic gas observed by Hunger and Johnson and the low fluorine analyses which they obtained on heated samples.Acknowledgments.-The single crystal spectra were photographed by F. A. Sherrill, whose assistance in this and in the correct elucidation of the powder patterns of K2POgF is gratefully acknowledged. The late G. E. Klein assisted in early stages of the investigation. The author is very grateful to W. R. Busing and H. A. Levy of the ORNL Chemistry Division for the use of several of their ORACLE codes and for much advice and assistance in performing the least squares refinements.