Salt spring in present rural world. An ethnoarchaeological approach in Moldavia (Romania)

The Subcarpathian area of Moldavia represents the ideal framework to perform extensive ethnoarchaeological research as there are here over 200 salt water springs near which are found archaeological deposits related to the exploitation of the salt water. Nowadays, these deposits are still exploited at an unexpected degree of intensity by the members of rural as well as of urban communities. The main research focuses on the identification of all salt springs in sub-Carpathian Moldavia and on the completion of complex ethnoarchaeological research (exploitation, use, distribution networks, commerce, hunting,halotherapy, social contexts, ethnoscience, symbolistics, etc.)

Biopolymer scleroglucan as an emulsion stabilizer

In this study, we investigated the Stabilization of bitumen emulsions by scleroglucan, a rigid triple-helix forming biopolymer, in combination with a pH-sensitive cationic surfactant. Various aspects of the emulsification process and the final composition influence the Stabilization. We examined two different methods to add scleroglucan to the emulsion: either by adding it to the aqueous surfactant solution before emulsification, denoted ‘pre-emulsification addition’ (pre-EA), or by addition to the emulsion after emulsification (post-EA). We investigated scleroglucan concentrations in the aqueous phase ranging between 0.017 and 0.07 w/w%. The emulsions were evaluated according to the European EN 13808 standard used for cationic bituminous emulsions, as well as by rheological analysis. We observed an improvement of the storage stability upon pre-EA at a biopolymer concentration as low as 0.017 w/w% in combination with an increased particle size, whereas the breaking index (characterising breaking of the emulsion in presence of ‘aggregates’ = stones) was not influenced. The rheological data show a minor viscosity increase by scleroglucan in the pre-EA formulation at low scleroglucan concentrations (0.017–0.05 wt.%) where Stabilization already improved dramatically. This indicates that the stabilization mechanism is not only governed by a viscosity increase but also by interfacial stabilisation effects were polymer is adsorbed onto the adsorbed surfactant. In a separate experiment we changed the conformation of scleroglucan by subjecting it to extreme pH values and by dissolution in DMSO, in order to study the role of the triple helix conformation in the stabilization mechanism. Scleroglucan becomes less effective in a denatured and hydrolysed state confirming the crucial role of the triple helix conformation in the Stabilization of bitumen emulsions.ChemE/Advanced Soft MatterOLD ChemE/Organic Materials and Interface

Cross-Linking of Multiwalled Carbon Nanotubes with Polymeric Amines

Functionalization of carbon nanotubes is considered as an essential step to enable their manipulation and application in potential end-use products. In this paper we introduce a new approach to functionalize multiwalled carbon nanotubes (MWNTs) by applying an amidation-type grafting reaction with amino-functionalized alternating polyketones. The functionalized MWNTs were characterized by using thermogravimetric analysis (TGA), X-ray photoemission spectroscopy (XPS), element analysis, Raman spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Around 40 wt % polyamines based on the total weight of the MWNTs can be covalently attached to the surface of the MWNTs. It is found that polyamines act as cross-linking agents to interconnect or cross-link the MWNTs within and between bundles, as demonstrated by SEM and TEM analysis. After cross-linking, the functionalized MWNTs are insoluble in any solvent. The cross-linked MWNTs can be melt-blended into polyethylene, and the resulting composites show comparable mechanical properties to those obtained by simple blending of “un-cross-linked” nanotubes with polyethylene.