Papers by Keyword: Polymorph

Abstract: The controlled solution spray process with superior molecular contacting between finely atomized reactants in impinging solution spray reactor was carried out with an objective to develop the nonionic surfactant (Tween-80) mediated coprecipitation protocol for the polymorph selective synthesis of lead chrome (PbCrO₄) nanocrystals. Monoclinic PbCrO₄ nanorods with size in the range of 37.8-51.9 nm at Tween-80 loadings of 2-10 g/L were obtained. The functional group, surfactant adsorption, crystal type, size and morphology of the PbCrO₄ nanocrystals were determined by FTIR, XRD and FESEM analysis.

Abstract: In this study, PVDF membranes were prepared by solution-cast method. The effects of evaporation temperature on the morphology, polymorph and mechanical properties of such prepared membranes were studied. It was found that perfect spherulites were observed in the solution-cast membranes. FESEM photomicrographs of the membranes showed dense structure. PVDF mainly crystallized into α phase. In the solution-cast process, the spherulite size increased as evaporation temperature was increased from 120 °C to 150 °C, when the evaporation temperature was 165 °C, spherulite size decreased. And the tensile strength increased with the decrease in spherulite size.

Abstract: Oven drying and microwave drying processes for GeO₂ after hydrolysis and filtration of GeCl₄ were performed, and then the polymorphs, surface morphology and chemical composition, etc. of GeO₂ were analyzed. The influence of microwave power and material thickness to GeO₂ moisture removal rate was researched in a single-factor-based test. The gained optimum process parameters for microwave drying GeO₂ are as below: microwave power is 400~550 W, material thickness for each time is 30~40 mm, and drying time for 1 kg GeO₂ is 36.67~40.00 mins. The results show that through the two processes, they can both gain GeO₂-06 products meeting national standard, and compare with them to obtain that microwave drying has the advantages of high efficiency, low energy consumption, no caking, etc.