| abstract |
Rigid-rod polymer fiber filaments, such as poly (p-phenylenebenzobisoxazole) (PBO), having improved retention of physical properties are prepared by preparing a polymer solution and extruding that solution to form a filament, and then treating that filament with water, base solution, and water. The treated filament may be further heat-treated, or further treated with water. The treated filaments are less susceptible to the degradation caused by heat, humidity, and UV radiation. |