| 摘要 |
Water-insoluble nitrogeneous polymerization products are made by polymerizing acrylamide alone or in admixture with other ethylenicallyunsaturated compounds, e.g. acrylonitrile, in a strongly acid aqueous solution of an inorganic acid in the presence of a polymerization promoter, e.g. ammonium persulphate, the limits of concentration of acid and the temperature being maintained such that no substantial amount of water-soluble products is formed and/or the water-absorbing power of the products are reduced in comparison with the products formed when the polymerization is carried out at a pH value not far removed from neutrality. Acids specified are sulphuric, phosphoric, hydrochloric, perchloric, nitric and toluene sulphonic acids and a hydrochloric acid-zinc chloride mixture. The concentration of acid employed is dependent on the acid used and is usually in excess of 2 per cent, and the polymerization temperature may be up to 120 DEG C. and is usually within the range of 60-100 DEG C. The polymerization medium may also contain ions of a metal of the third to eighth group of the Periodic System, e.g. iron, and a wetting or emulsifying agent. The polymeric products have a nitrogen content which is lower than that of the monomeric starting materials.
|
