Search results for "medium"
showing 10 items of 3746 documents
Voltammetric Identification of Lead(II) and (IV) in Mediaeval Glazes in Abrasion-Modified Carbon Paste and Polymer Film Electrodes. Application to th…
2000
Direct identification of lead(II) and (IV) in glazed ceramics by cyclic voltammetry and differential pulse voltammetry is described. Characteristic cathodic and anodic profiles are obtained for microsample coatings in Paraloid B72-film electrodes immersed in NaCl and HAc/NaAc media. The electrochemical response of PbO, PbO2 and Pb3O4, and a series of test specimens of glaze is compared with that of microsamples extracted from the glaze of blue and white decorated ceramic produced in Manises (Spain) in the 15th century which have been buried in a damp place. Under abrasive conditions, striping peaks at –0.12 and –0.25 V (vs. SCE) appear for Pb(IV) centers and, at –0.55 and –0.75 V, for Pb(II…
Bicyclo[2.2.2]octane-1,4-dicarboxylic acid: towards transparent metal–organic frameworks
2017
The preparation of transparent porous materials can offer a different access towards the study of molecules under solid confined space. Metal-organic frameworks represent a unique opportunity due to their tunable pore size, however aromatic linkers present strong absorption and reduce the transparency. Herein, we report the first example of a MOF with bicyclic organic dicarboxylic linkers and its use as a solid solvent.
Dendrimer-encapsulated and cored metal nanoparticles for electrochemical nanobiosensing
2014
Abstract We discuss nanosized dendrimers from the point of view of electrochemical-biosensor design. We review electrochemical biosensors based on dendrimer-encapsulated metal nanoparticles (NPs) and their various applications (e.g., measurement of small biological and toxic molecules, detection of DNA, and immunosensing of disease biomarkers). Finally, we discuss some future applications of electrochemical biosensors based on dendrimer-encapsulated metal NPs.
Einfluss des polymerrückgrats auf eigenschaften von thermoplastischen elastomeren
1992
4-Urazoyl benzoic acid groups were statistically attached to various hydrocarbon elastomers, polar elastomers and partially crystalline polymers via a polymer-analogous reaction. DSC, FTIR, stress-strain experiments and dynamic-mechanical analysis were used to analyse whether these systems, analogous to functionalized polybutadienes, would form ordered supra-molecular structures of the polar side-groups that would lead to a thermoreversible crosslinking. While the structure formation is suppressed for elastomers with a large cross-sectional area of the chain (e.g. butyl rubber) or polar side-groups, (e.g. polychloroprene), the mechanical propertie can be controlled by balancing supermolecul…
Heads or Tails? Sandwich-Type Metallo Complexes of Hexakis(2,3-di-O-methyl)-α-cyclodextrin
2020
Native and synthetically modified cyclodextrins (CDs) are useful building blocks in the construction of large coordination complexes and porous materials with various applications. Sandwich-type co...
Iron oxide-based magnetic photocatalysts: Recent developments, challenges, and environmental applications
2021
Abstract Magnetic separation of the solid photocatalyst from the reacting suspension has received great interest in recent research because it offers a suitable way for removing and recycling the heterogeneous photocatalytic material particles preventing the agglomeration and sedimentation during and after their use. The use of iron oxides such as heterogeneous photocatalysts is an appropriate choice to obtain a suitable photocatalyst easily separable from the fluid. This chapter presents a detailed investigation of iron oxide-based magnetic photocatalysts (IOMPs). We will discuss the required conditions for the synthesis of these photocatalysts, followed by their applications for the remov…
Reactive dual-component compatibilizers for polycarbonate/high-density polyethylene blends
1995
Enhanced compatibility for blends of polycarbonate with high-density polyethylene has been achieved with the addition of 5 wt% compatibilizers composed of 1 : 1 mixtures of phenoxy and the sodium ionomer of an ethylene methacrylic acid copolymer at two different levels of neutralization. Both components of the compatibilizer have been found to be capable of reacting with the polycarbonate phase to produce branched polymer chains. These impart a degree of compatibilization in polycarbonate/high-density polyethylene blends, however at higher levels of sodium in the compatibilizer the polycarbonate phase undergoes crosslinking reactions, causing severe embrittlement. Compatibilization effects …
Biologizing titanium alloy implant material with morphogenetically active polyphosphate
2015
As a further step towards a new generation of bone implant materials, we developed a procedure for biological functionalization of titanium alloy surfaces with inorganic calcium polyphosphate (Ca-polyP). This polymer has been demonstrated to exhibit morphogenetic activity. The coating of titanium oxidized Ti-6Al-4V scaffolds with biologically active amorphous Ca-polyP microparticles is formed by Ca2+ ion bridges to the silane coupling agent APTMS. This surface is durable and stable as an almost homogeneous Ca-polyP layer onto the metal. The homogenously coated Ca-polyP titanium scaffold was found to be biologically active and supported the growth and functional activity of bone cell-related…
QENS investigation of filled rubbers
2002
The polymer segmental dynamics is investigated in a series of silica-filled rubbers. The presence of inert fillers in polymers greatly affects the mechanical and physical performance of the final materials. For example, silica has been proposed as a reinforcing agent of elastomers in tire production. Results from quasielastic neutron scattering and Dynamic Mechanical Thermal Analysis (DMTA) measurements are presented on styrene–ran-butadiene rubber filled with silica. A clear indication is obtained of the existence of a bimodal dynamics, which can be rationalized in terms of the relaxation of bulk rubber and the much slower relaxation of the rubber adsorbed on the filler surface.
Prediction method of electrical conductivity of nano-modified glass fibre reinforced plastics
2019
Glass fibre reinforced plastics (GFRP) is non-conductive construction material, however with carbon nanotubes (CNT) modifying it can get additional functionality due to its gained electrical conductivity. Main aim of the study is to check functionality of the prediction method of electrical conductivity of GFRP with nano-modified epoxy matrix using structural approach. GFRP composites under investigation were based on unidirectional (UD) Glass fiber and two matrixes modified with carbon nanotubes. Electrical conductivity of epoxy resin modified by CNT (concentrations < 1%) was modelled using structural approach. Electrical conductivity of unidirectional GFRP layer was measured experimentall…