摘要:
In a secondary battery employing an aqueous lead salt solution as the electrolyte, salts of manganese, cobalt, nickel, copper, thallium, bismuth and/or antimony are additionally present in concentrations of from 0.1 to 100 mmole/l.
摘要:
Glass-fiber-reinforced thermoplastic molding compositions showing improved flowability and toughness and containing from 0.1 to 2% by weight, based on the total mixture, of a low molecular weight polyolefin wax to which from 2 to 50% by weight of polar side chains have been grafted.
摘要:
Thermoplastic molding compositions comprise a linear nylon, an adduct of hexachlorocyclopentadiene and a dienophile as a flameproofing agent, zinc oxide as a synergistic agent, and reinforcing fillers. The zinc oxide is manufactured by adding an aqueous solution of a zinc salt and an aqueous solution of a base to an aqueous suspension of an inorganic carrier, the zinc oxide being precipitated at a pH of from 10 to 12. The molding compositions can be processed to give flameproof moldings having good mechanical properties.
摘要:
A process for the preparation of polyurethane foams modified with melamine-formaldehyde precondensates, in which the precondensates employed are storage-stable, aqueous 40-85% strength by weight resin solutions which are obtained by condensing melamine with formaldehyde in a molar ratio of 1:1.1-1.75 in aqueous solution at a pH which, at least periodically, is above 8, and at from 60 to 130.degree. C., until one part by volume of resin solution can be diluted with from 0.5 to 4 parts by volume of water at 20.degree. C. without causing a persisting cloudiness.
摘要:
A process for making a polyurethane which comprises reacting an organic polyisocyanate with a higher molecular weight organic polyhydroxyl compound in the presence of a catalyst having the following formula: ##STR1## wherein X is sulfur or NH and n is a whole number from 2 to 6. Also used is a catalyst which is a combination of the above-mentioned catalyst and an organic tin compound.
摘要:
Hydrophobic polyurethane foams which have densities of from 4 to 15 g/liter and in which the number of closed cells is from 2 to 30%, and the number of open cells from 98 to 70%, based on the total number of cells, are obtained from polyisocyanates, polyhydroxy compounds, catalysts and water, with or without lipophilic compounds, the components being reacted in such amounts that the ratio of hydrogen atoms capable of undergoing a Zerewitinoff reaction to NCO groups is from 1.3 to 10:1. The foams are suitable for the absorption of oil and/or by hydrophobic solvents, which may or may not contain halogen, from water.
摘要:
An accumulator having an acid electrolyte and possessing two electrodes of the first kind mounted on base electrodes. The active material on the positive side contains manganese dioxide. The base electrode on the negative side consists of powdered graphite embedded in a binder which is resistant to the electrolyte. The base electrode on the positive side has a coarse porous structure and consists of graphite or titanium coated with titanium nitride or titanium carbide. The average pore diameters are from 0.1 to 2 mm and the pore volume is from 20 to 70%.
摘要:
Secondary batteries with aqueous acid solutions of lead salts as electrolytes and inert electrode base plates also contain redox systems in solution. These systems have a standard potential of from -0.1 to +1.4 V relative to a standard hydrogen reference electrode, do not form insoluble compounds with the electrolytes and are not oxidized or reduced irreversibly by the active compositions applied to the electrode base plates, within their range of operating potentials.
摘要:
Thermoplastic molding compositions based on polybutylene terephthalate having a relative viscosity of from 1.3 to 2.0, as measured in a phenol/o-dichlorobenzene mixture at 25.degree. C, and which contain, to increase the thermo-aging stability and toughness and also to improve the processing stability, from 0.1 to 10% by weight, based on the polybutylene terephthalate, of isocyanates or isothiocyanates and/or carbodiimides and/or compounds forming isocyanate groups or isothiocyanate groups and/or carbodiimide groups.
摘要:
A process for separating hydrophobic organic liquids from water comprising passing a mixture of water and hydrophobic organic liquids through a column-like vessel which is filled with a hydrophobic, preferably open-celled, polyurethane foam, said foam having a high absorption capacity, permits high flow-through velocities even as the foam becomes covered and saturated with the hydrophobic organic liquids, is reversibly deformable, and can be reused.