Polylactide/Biopolyethylene bioblends
In this work, Polylactide/Biopolyethylene blends were developed. Although some studies have been carried out on polylactide/polyethylene blends, none of them has used polyethylene synthesized with raw material obtained from natural sources. Due to the incompatibility between polylactide and polyethylene, E-GMA and EMA-GMA compatibilizers were used. These compatibilizers present glycidyl methacrylate groups in their structure, which may react with the functional end-groups of polylactide. To evaluate the properties, the blends were characterized by mechanical tests, scanning electron microscopy (SEM) and melt flow index (MFI). The results indicated that the compatibilizers played an important role in the blends, interacting with the blends components, modifying the morphology and improving the mechanical properties.
Blenda de náilon-6,6/quitosana como adsorvente de corantes ácidos para reutilização das soluções de corantes tratadas em tingimentos de poliamida
Water is used in the textile industry, mainly, as vehicle for chemicals and dyes used in the dyeing and finishing processes of textile fibers. In this work we studied the reuse of wastewater generated in the dyeing of nylon 6.6 (PA6.6) fabrics and treated by adsorption process with nylon 6.6/chitosan (80/20) blend flakes was studied. To produce the wastewater PA 6.6 fabrics were dyed with the acid dyes Yellow Erionyl RXL, Red Erionyl A-3B and Navy Blue Erionyl R. The efficiency in color removal of the adsorption process varied between 97-98%, with exception of the effluents from Yellow Erionyl RXL dyeing, where only efficiencies of 65% (wastewater with auxiliaries) and 72% (without auxiliaries) were obtained. The reuse of the treated wastewater was studied in dyeing of knitted nylon 6.6 fabrics with the same dyes. ΔE values (color difference relative to a standard dyeing with distilled water) of the dyeings with light and medium colors varied from 0.24 to 1.05 for the wastewater of monochrome dyeing, and from 0.71 to 1.07 for the wastewater of trichrome dyeing and are compatible with industrial standards (ΔE < 1.1). It could be concluded that the reuse of treated wastewater from polyamide dyeing under the tested conditions is feasible, although with some restrictions for yellow especially.
Refinement of crystal structure parameters using convergent‐beam electron diffraction: the low‐temperature phase of SrTiO3
The method to refine crystal structure parameters (atom positions and Debye–Waller factors) using convergent-beam electron diffraction (CBED), which is applicable to crystal structure analysis of a small specimen area down to a few nm in diameter, is studied. The line profiles of higher-order Laue-zone reflections are recorded using imaging plates. Theoretical intensities are calculated based on the dynamical theory of electron diffraction with the aid of the generalized Bethe approximation to shorten calculation time. The structural parameters are determined by fitting the experimental profiles with the theoretical ones using a nonlinear least-squares method. The present method has been applied to the low-temperature phase of SrTiO3. The structural parameter or the rotation angle of the oxygen octahedron has been determined to be \varphi = 1.12 (4)°, which shows good agreement with that obtained from electron spin resonance experiments.