Abstract: The invention relates to metal nanoparticles and a process for the preparation thereof, in which a metal salt solution is reduced with a reducing agent in the presence of the derivatized polyethyleneimines or polyvinylamines. Metal salt solutions of two or more different metals can be reduced simultaneously or in succession, metal nanoparticles comprising two or more different metals being obtained. Preferred metals are silver, palladium, and platinum. Suitable reducing agents are, for example, formic acid, formaldehyde, diethanolamine, 5-pentenoic acid and sodium borohydride. Silver can be used in the form of silver oxide and/or silver nitrate, palladium in the form of alkali metal tetrachloropalladate or palladium(II) nitrate and platinum in the form of alkali metal tetrachloroplatinate or tetraamineplatinum(II) nitrate.

Abstract: Disclosed is a method for determining the swellability and the swelling kinetics of superabsorbent material (9) such as polymer gels, for example, which comprises introducing a defined volume of the dry superabsorbent material (9) into a measuring vessel (7), using a movable element (4) within said measuring vessel (7) to apply a restraining force (12) to said superabsorbent material (9) and capturing the expansion of said superabsorbent material (9) contactlessly within a chamber (14) in a continuous manner by capturing the change in height of a piston (4) which bounds said chamber (14), travels in a measuring vessel (7) and is marked with a height scale (6).