| 摘要 |
When modifying a hollow polymeric fiber by stretching of its precursor, a fiber bundle with the length L is stretched in a first step at a temperature ranging from 20 to 30 degC for a length of Li1, which exceeds by 1.5 to 2 multiple the stretching length Li2 at the same temperature. After relief of drawing force, the length Li2 results in permanent elongation of the original length L by 5 to 8 percent. In the second step, the fiber bundle is heated without release of pull to a temperature in the range of 40 to 45 degC and at this temperature is stretched by 9 to 30 percent of the length Li1. In the third step, the temperature is increased to the range of 95 to 110 degC, and at this temperature value the fiber bundle is stretched without relief of pull by 30 to 55 percent of the length Li1, whereupon in 15 minutes at the most it is cooled down to a temperature in the range of 20 to 30 degC. |
