Colloid/nanoparticle formation and mobility in the context of deep geological nuclear waste disposal (Project KOLLORADO-2) ; final report (KIT Scientific Reports ; 7645)

To assess the relevance of colloidal influences on radionuclide transport for the long-term safety of a radioactive waste repository, the KOLLORADO-2 project integrates the results of geochemical and hydrogeological studies. The results may serve as a basis for an appraisal of the implications of colloid presence in the vicinity of radioactive waste repositories in different deep geological host-rock formations

Monitoring the influence of different weathering conditions on polyethylene pipes by IR-microscopy

Plastic pipes are often exposed to a range of environmental conditions which may lead to their degradation. The most important influence factors are UV radiation, humidity and temperature. These can cause leaching of long-term and light stabilisers and finally oxidation of the polymer. In this study we demonstrate how the elemental steps of the photooxidative degradation of polyethylene pipes can be monitored by IR-microscopy. In detail the influence of UV radiation leads to a depletion of the phenolic long-term stabiliser, Irganox 1010. Calibration of the spectroscopic data enables IR-microscopy to be carried out in a quantitative manner and the rate constants for the stabiliser loss to be calculated for the first time. The results obtained from IR-microscopy are well in agreement with those obtained by mechanical sample preparation and measurement of the oxidative induction time (OIT) as well as extraction coupled with chromatographic analysis (HPLC). A mechanism based on Norrish type cleavage is proposed. Also the formation of trans-vinylidene groups as unsaturated degradation products of the PE can be observed. In summary it can be shown that IR-microscopy is highly superior to the conventional approach of mechanical sample preparation with regard to spatial resolution and offers the advantage of being less labour intensive

Tensile and water barrier properties of cassava starch composite films reinforced by synthetic zeolite and beidellite Journal of Food Engineering.

International audienc

Electrospuns including clay and ordered mesoporous silica materials

This study has been conducted to produce nanofibers charged with synthetic clays (montmorillonite and laponite) or ordered mesoporous silica by electrospinning process. The first challenge of this project was to analyse and optimize the dispersion of these particles into the olyacrylonitrile(PAN)/Dimethylformamide(DMF)solution. Solutions have been prepared with special mechanical treatment to make them homogeneously dispersed before the electrospinning process. Morphology and homogeneity have been checked by Scanning Electron Microscopy (SEM). It has been observed that the mechanical treatment changes the dispersion of the fillers inside the nanofibers. The key parameters controlling the dispersion and the spinning have been determined and optimized. The diameters have been measured by using Image J software. Influence of spinning parameters has been investigated to compare the nanocomposites homogeneity in terms of fibers diameter and particles dispersion