SYNTHESIS AND PROPERTIES OF POWDERY HYDROGELS BASED ON ACRYLAMIDE, METHACRYLAMIDE, AND THEIR N-SUBSTITUTED DERIVATIVES

Lightly crosslinked hydrogels based on acrylamide, N-(1,1-dimethyl-3-o xobutyl)-acrylamide, N,N-dimethylacrylamide, methacrylamide, N-(2-hydr oxypropyl)methacrylamide and N-[tris(hydroxymethyl)methyl]methacrylami de were synthesized in form of fine powders, consisting of aggregates of very small (similar to 10(-1) mu m) particles. The powdery hydrogel s were obtained by precipitation polymerization in acetone and diethyl ether, using N,N'-methylenebisacrylamide and ethylene dimethacrylate as crosslinking agents. Dependences of water-swellability, particle si ze, aggregation, specific surface and content of the uncrosslinked wat er-soluble polymers and low-molecular-weight substances in the hydroge ls on the conditions of their synthesis were studied. Suitability of p articular powdery hydrogels synthesized for the preparation of silicon e rubber - hydrogel composites is discussed.