摘要:
The invention provides a process for determining surface contamination of polycrystalline silicon, including the steps of: a) providing two polycrystalline silicon rods by deposition in a Siemens reactor; b) determining contaminants in the first of the two rods immediately after the deposition; c) conducting the second rod through one or more systems in which polycrystalline silicon rods are processed further to give rod pieces or polysilicon fragments, optionally cleaned, stored or packed; d) then determining contaminants in the second rod; wherein the difference in the contaminants determined in the first and second rods gives surface contamination of polycrystalline silicon resulting from systems and the system environment.
摘要:
Process for preparing one or more complexing agents selected from methylglycinediacetic acid, glutamic acid diacetic acid and salts thereofProcess for preparing one or more complexing agents selected from methylglycinediacetic acid, glutamic acid diacetic acid and salts thereof by catalytic dehydrogenation of N,N-bis(2-hydroxyethyl)alanine and/or N,N-bis(2-hydroxyethyl)glutamic acid and/or salts thereof in the presence of alkali metal hydroxide, where a catalyst comprising copper and zirconium dioxide is used, the activation of which is a reduction, wherein the precursor of the catalyst in question has a degree of crystallization K, defined as K = I K · 100 I K + I A , in the range from 0 to 50%.
摘要:
The invention relates to a cementitious composition that can effectively reduce the adsorption of water, which comprises a) at least one polymer that is the polymerization product of one or more ethylenically unsaturated monomers, in the form of their polymer dispersions and water-redispersible polymer powders; and b) at least one alkyl and/or alkenyl substituted dicarboxylic acids or anhydrides.
摘要:
A water redispersible polymer powder is produced by drying an aqueous mixture of a high Tg carboxylated styrene butadiene polymer and a low Tg carboxylated styrene butadiene polymer, where the ratio of the mean or average particle size of the high Tg polymer to the particle size of the low Tg polymer is from 1:1 to 5:1, preferably from 1:1 to 3:1, and the amount of the high Tg polymer is from 20 wt. % to 35 wt. %, preferably from 25 wt. % to 30 wt. %, based upon the total weight of the high Tg polymer and the low Tg polymer. Cement compositions such as mortars, which contain the redispersible polymer powder exhibit unexpectedly superior high bond strength and high impact resistance.
摘要:
The present invention provides compositions comprising redispersible polymer powders of polyolefins with carboxyl group containing dispersant polymers and vinyl ester copolymers which may further comprise hydraulic or water curable inorganic cements for various construction applications, such as cement tile adhesives. Methods of making redispersible polymer powders of polyolefins are also provided, including forming an aqueous polyolefin dispersion, such as, for example, by mechanical dispersion, followed by drying to form the redispersible polymer powders.
摘要:
What is proposed is a process for preparing aminopolycarboxylates proceeding from the corresponding polyalkanolamines by oxidative dehydrogenation in the presence of a catalyst comprising 1 to 90% by weight of copper, based on the total weight of the catalyst, using a base, which comprises first performing a partial conversion of the polyalkanolamine to a reaction mixture comprising the aminopolycarboxylate at a temperature in the range from 140 to 180° C. until at least 10 to 90 mol % of the polyalkanolamine has been depleted, and then continuing the conversion at elevated temperature.
摘要:
The present invention relates to polysaccharide derivatives having an adjusted particle morphology for use in the preparation of a hydrolytically setting composition having an adjusted lump rating. The invention further relates to a method of adjusting the lump rating of a hydrolytically setting composition comprising adjusting the particle morphology of a particulate polysaccharide derivative. Furthermore, the invention is directed to a hydrolytically setting composition comprising a particulate polysaccharide derivative having an adjusted particle morphology. The invention is also directed to various uses of the particulate polysaccharide derivative having an adjusted particle morphology.