| 摘要 |
Coloured tetrafleuoroethylene resin filaments are bleached by treating them with a mixture of sulphuric, nitric and perchloric acids. The filaments may be treated with a solution of 1 part by weight of concentrated HNO3, 1 part by weight of concentrated H2SO4 and 2 parts by weight of HClO4 (70%) for about half an hour, during which time the solution is brought to the boil at about 285 DEG F., and heating continued to raise the boiling point to about 375 DEG F., after which 1 part by weight of HClO4 is added and the treatment continued for another half an hour. The filaments may be used for making artificial blood vessels. |
