| 摘要 |
A redox polymer comprises a matrix composed of a cross-linked copolymer of monoethylenically unsaturated monomer and polyethylenically unsaturated monomer, the matrix having attached thereto mercapto groups or the corresponding oxidized groups containing disulphide linkages, characterized in that the matrix possesses a macroreticular structure. Initially, a macroreticular matrix polymer is prepared from a monoethylenically unsaturated/polyethylenically unsaturated monomer charge by polymerization in the presence of an inert liquid precipitant which is a solvent for the monomer charge but is inert towards the resulting copolymer, thereby causing phase separation of the resulting copolymer to take place. The precipitant in the minute channels formed within the copolymer is then removed by drying. Mercapto groups are introduced into the macrorecticular copolymer by first halomethylating the copolymer with a halomethylether in the presence of a Friedel-Crafts catalyst and a swelling agent, reacting this with thiourea, a substituted thiourea or an alkali metal hydrosulphide and then hydrolysing this intermediate product. The copolymer is preferably prepared from at least one monoethylenically unsaturated aromatic compound such as styrene, vinyl toluene or vinyl naphthalene and at least one polyethylenically unsaturated monomer such as divinyl benzene, divinyl toluene, ethylene glycol dimethacrylate, trivinyl benzene, divinoxyethane or trivinoxypropane. Suitable liquid precipitants are C4- 10 alkanols such as n-butanol, t-amyl alcohol and decanol. The thiourea, substituted thioureas or alkali metal hydrosulphides which are preferably used in a solvent, e.g. ethanol may be N-methylthiourea, N-phenylthiourea, N-tolylthiourea, N-acetylthiourea, N,N-dimethylthiourea, sodium or potassium hydrosulphide. As a comparison to the above macroreticular copolymers, a conventional copolymer is formed in bead form by chloromethylating a styrenedivinylbenzene copolymer containing 3% divinylbenzene with chloromethyl ether and after swelling said beads with dioxane, mercapto groups are introduced by refluxing with a solution of thiourea in ethanol and then hydrolysing the beads with a solution of sodium hydroxide in ethanol. |
