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An investigation specifically focusing on the relationship among processing parameters, structure, and mechanical properties of solid two-stage die-drawn polypropylene (PP) has been done in this study, which aimed at providing a reliable reference in the choose of appropriate conditions that can be able to meet a specific processing requirement. PP sheets were drawn through a self-design solid two-stage die-drawing apparatus to various drawing ratios (DRs) at different speeds and with different die-exit thicknesses. The results showed that tensile strength, modulus, and the degree of orientation significantly increased with the nominal DR and could be further improved by increasing the drawing speed. While the crystallinity increased prior and decreased to near a constant value when the drawing speed was over 150 mm/min in the researched scope. Larger the die-exit thickness was, lower the orientation degree was but higher the crystallinity could be obtained. Compared with crystallinity, orientation degree plays a leading role in the final product properties during a two-stage solid die-drawing process., INTRODUCTION Polymer and polymer composites have been widely applied in various fields like commodity, engineering, medical materials, and so on [1], As known, the inner structure and morphology are decisive [...]

Abstract: SnO2 nanocrystals were synthesized by a precipitation process and then used as the support for Au/SnO2 catalysts preparation via a deposition–precipitation method. The samples were characterized by means of X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM)/energy-dispersive X-ray spectra (EDS) and X-ray photoelectron spectroscopy (XPS). The influence of calcination temperature of SnO2 support, calcination temperature of Au/SnO2 catalysts and Au loading on the catalytic activity of Au/SnO2 catalysts was investigated. The SnO2 samples calcined at 573 and 673K were found to be the suitable support materials for Au/SnO2 catalysts. In all investigated Au/SnO2 catalysts with different Au loading from 0.36 to 5.00wt.%, the catalytic activity of the catalyst with 2.86wt.% Au loading was the highest. The optimum calcination temperature of the Au/SnO2 catalysts was 473K. According to XRD, HRTEM and XPS, the catalytic activity of the Au/SnO2 catalysts was related to the particle size of gold and tin oxide support, the fraction of metallic state Au and the degree of crystallinity of tin dioxide support. [Copyright &y& Elsevier]