| 摘要 |
A curing composition for curing a polysulphide polymer, which composition comprises as the curing agent sodium birnessite, Na4Mn14O27.9H2O. A process for the preparation of sodium birnessite comprises the steps of adding an excess in the range of from 25% to 225% of a solution of sodium hydroxide to a solution of manganese (II) chloride or manganese (II) sulphate to form a slurry of manganese (II) hydroxide and passing air free of carbon dioxide therethrough for at least 3 hours or oxygen for 1.5 hours, these steps being carried out at ambient temperature. The compositions are very rapid curing agents for curing polysulphide polymers. |
