Authors:Z. Song, X. Huang, Z. Xie, Q. Ge and R. Wang
The residual fluorine in ammonium uranyl tricarbonate (AUC) cannot be removed, while a large part of residual fluorine in
ammonium diuranate (ADU) can be removed, when AUC and ADU are decomposed and reduced under dry hydrogen atmosphere. UO2 was prepared by decomposing and reducing AUC and ADU in dry hydrogen atmosphere. The defluorination kinetics of UO2 at 500–700°C in atmosphere of 50% H2-50% H2O was investigated. The results show that the defluorination kinetics supports the Lindman's assertion that the residual fluorine
forms a solid-solution in UO2.
Polyvinyl chloride (PVC)/organic-montmorillonite composites were prepared by melt intercalation. Their structures and properties
were investigated with X-ray diffraction (XRD), differential scanning calorimetry (DSC) and mechanical testing. The results
showed that PVC chains could be intercalated into the gallery of organically modified montmorillonite to form exfoliated PVC/organic-montmorillonite
nanocomposites, and the glass transition temperatures of PVC/organic-montmorillonite composites were lower than that of neat
PVC. However, the tensile strength, and both the Izod type and Charpy notched impact strengths of PVC/organic-montmorillonite
nanocomposites were fitted with the linear expressions: t=535.07-6.39Tg, sI=378.76-4.59Tg and sC=276.29-3.59Tg, respectively.
Authors:H. Quan, Z. Ge, Z. Li, C. Yin, K. Zhong, Z. Hao, H. Li and F. Ji
The desorption behaviour (desorption temperature and extent of desorption) of HF,HCFC-133a (CF3CH2Cl) and HFC-134a (CF3CH2F) on γ-AlF3 or catalyst supported on γ-AlF3 was studied using an adsorption apparatus and TG, DTA and DSC methods. On the basis of the results a reaction mechanism was
proposed for the preparation of HFC-134a. The γ-AlF3 employed for preparing the catalyst was expected to be stable below 550C based on the crystalline phase transition temperature