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The influence of the plasticizer content and film preparation procedure on the morphology, density, thermal and mechanical properties of cellulose acetate (CA) films plasticized with poly-(caprolactone triol) (PCL-T), were studied. Differential scanning calorimetry (DSC), thermal mechanical analysis (TMA), scanning electron microscopy (SEM), wide-angle X-ray diffraction (WAXD) and infrared spectroscopy (FT-IR) techniques were used. The films were prepared by dry-casting CA and CA/PCL-T in acetone or acetone/water solutions, which produced transparent and opaque films, respectively. In contrast to the transparent films, which were dense, the opaque films presented a porous morphology. However, the presence of PCL-T reduced the opaque film porosity, increasing, in consequence, its bulk density. The TMA results revealed that PCL-T reduced the glass transition temperature more significantly in the transparent than in opaque films. Only the transparent CA/PCL-T films presented a melting temperature, that reduced with higher concentrations of PCL-T, suggesting a higher ordering (crystallinity) when the films were prepared in the absence of water, as observed from WAXD curves. The mechanical properties also showed that the transparent films were more soft and tough than the opaque films. In summary, PCL-T was a good plasticizer agent for CA films due to the presence of hydrogen bonds between the components (FT-IR spectra). The presence of water in the dry casting process has a significant effect mainly on film morphology and mechanical properties.

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The local atomic structure of an amorphous NiZr2 alloy was investigated using the anomalous wide-angle x-ray scattering (AWAXS), differential anomalous scattering (DAS) and reverse Monte Carlo (RMC) simulations techniques. The AWAXS measurements were performed at eight different incident photon energies, including some close to the Ni and Zr K edges. From the measurements eight total structure factor S(K, E) were derived. Using the AWAXS data four differential structure factors DSFi(K, Em, En) were derived, two about the Ni and Zr edges. The partial structure factors SNi-Ni(K), SNi-Zr(K) and SZr-Zr(K) were estimated by using two different methods. First, the S(K, E) and DSFi(K, Em, En) factors were combined and used in a matrix inversion process. Second, three S(K, E) factors were used as input data in the RMC technique. The coordination numbers and interatomic distances for the first neighbors extracted from the partial structure factors obtained by these two methods show a good agreement. By using the three-dimensional structure derived from the RMC simulations, the bond-angle distributions were calculated and they suggest the presence of distorted triangular-faced polyhedral units in the amorphous NiZr2 structure. We have used the Warren chemical short-range order parameter to evaluate the chemical short-range order for the amorphous NiZr2 alloy and for the NiZr2 compound. The calculated values show that the chemical short-range order found in these two materials is similar to that found in a solid solution.

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