STUDIES ON THE CARBONIZATION OF POLEACRYLNITRILE FIBER
(I) CHANGES IN MECHANICAL PROPERTIES WITH HEAT-TREATMENT
1965 Volume 21 Issue 12 Pages 635-639
Details
1965 Volume 21 Issue 12 Pages 635-639
Flame-proofed fiber and fabrics, prepared by oxydative heat-treatment of polyacrylonitrile, were further heat-treated for 40 min. at various temperatures up to 1000°C in a nitrogen atmosphere. Weight-loss, shrinkage and some tensile properties were measured as a function of temperature. Results may be summarized as follows:
1. In both fiber and fabrics, weight-loss and shrinkage increase as the treatment by 60_??_70% and 13_??_20%, respectively temperature is raised up to 1000°C. Shrinkage of the fabrics seems to be larger than that of the fiber at all stages.
2. The tenacity and Young's modulus of the fibers increase and the breaking elongation decreases as the temperature of treatment is increased. There is an inflection point at around 500°C on the curves of the Young's modulus and elongation v. s. temperature.
3. In contrast to the results on the fiber, tensile strength of the fabrics tends to decrease by increasing the temperature of treatment. The brittle short fibers contained in the yarn will be ruptured by the shearing force, thereby causing the weaker strength of fabrics than that of the fiber.
4. Resistance to surface abrasion of the flame-proofed fabric seems to be improved by treatment at 500°C.
