| 摘要 |
<p>Solid polymeric materials are made by oxygenating an ester derived from methacrylic acid and a glycol, containing at least two methacrylate groups and having one or more ether linkages in the glycol portion, by passing oxygen through the ester at a temperature of 25 DEG C. to 90 DEG C. until at least 0.1 per cent of combined oxygen is introduced, and thereafter excluding oxygen while effecting polymerization. Esters specified are the dimethacrylates of diethylene, triethylene, tetraethylene, polyethylene, dipropylene, and dipentamethylene glycols, and diglycerol tetramethacrylate. Oxygenation may be carried out with air, oxygen, or ozone, or mixtures thereof, and may be accelerated by the addition of a small quantity of a peroxide such as benzoyl peroxide, tert.-butyl perbenzoate, di-tert.-butyl perphthalate, and tert.-butyl hydroperoxide, or by the addition of a small quantity of the oxygenated monomer obtained previously. After oxygenation the monomer does not undergo polymerization whilst still in contact with oxygen or air, but under anaerobic conditions polymerization takes place rapidly at room temperature. If desired a mixture of a glycol dimethacrylate and monomethacrylate may be oxygenated and then polymerized. The polymerization of the oxygenated esters may be used in bonding applications and in sealing leaks. Specifications 549,234 and 573,175 are referred to.ALSO:Diethylene glycol monoethyl ether monomethacrylate and diglycerol tetramethacrylate are prepared by heating respectively diethylene glycol monoethyl ether and diglycerol with methacrylyl chloride, and then, at the end of the reaction, removing excess methacrylyl chloride and residual hydrochloric acid in a vacuum. Specifications 549,234 and 573,175 are referred to.</p> |
