There are many methods for the surface-modification of powder materials to get the high functionality, such as fluidity, dispersibility, and so on. Commonly used coupling agents react with the surface functional group, especially hydroxyl group, through the formation of chemical bonds, and also the many techniques are applied according to the chemical properties of those agents and the powders. In this paper, our research results of some modification techniques using mainly alcohols and silane coupling agents and the surface characterization methods are described including the historical context.
Transfer efficiencies of air spraying and electrostatic rotary-bell spraying have been simulated using a 2-dimensional model and a motion equation. The orbits of paint droplets with various diameters near the substrate were calculated from measured specific charge, droplet velocity, air velocity, and so on. The transfer efficiency was estimated as the ratio of nonvolatile weight of droplets arrived at the substrate to that of all droplets.
To increase the transfer efficiency in terms of practical use, optimization of atomization, increase in specific charge and/or electric field, and narrowing of spray pattern where necessary are effective.
Though inkjet coating is expected as the coating technology of 100% transfer efficiency, it will be impossible to substitute it for electrostatic rotary-bell spraying in the painting process of car bodies, unless the productivity (coated area per time) is improved drastically.
The composition formula of a molecule can be estimated by high resolution mass spectrometry, molecular structure analysis can be performed in the case of a polymer material which is known to have a constant repeating unit. On the other hand, since the polymer has a distribution in molecular weight, the high resolution mass spectrum is complicated, and the analysis is often difficult. Here, we explain the features of high resolution mass spectrometry and introduce two examples on high resolution mass spectrometry of polymers.
The NMR-metabolic profiling (MP) methodology, a combination of 1-D 1H-NMR measurement and statistical pattern recognition, is a very powerful and forthright approach for mixture solution analysis. It can skip purification process to get a target compound, or even sample preparation. It also may omit detailed analysis of each spectrum. Consequent exploratory analysis by removing key variable(s) with step by step manner, and/or by adding/removing numeric sample data from data set could suggest useful information to understand complex situation.