紫外线辐照对棉纤维结构与性能的影响

Effect of UV irradiation on structure and properties of cotton fibers

为探究紫外线(UV)辐照对棉纤维结构与性能的影响,详细分析了棉织物经不同时间的UV(功率密度为100 W/cm)照射后,其表面形态、聚合度、力学性能、热稳定性、白度的变化。结果表明:辐照时间的增加会使棉纤维结构与性能的损伤增大,当辐照时间达到30 s,棉纤维的表面被刻蚀,表面粗糙度增加;在初始裂解阶段棉纤维的失重率略微增加,棉纤维最大失重速率温度下降8℃,热稳定性有所下降;棉织物白度下降7%,织物泛黄;棉纤维素大分子中共价键C—C、C—O断裂,棉织物的经向断裂强力下降约21%,纬向断裂强力下降约10%;棉纤维聚合度从692下降到140。随着辐照时间的进一步延长,棉纤维结构与性能的损伤程度增加会更大。

The cotton fabric was irradiated for different time periods under UV to investigate the effect of UV irradiation on the structure and properties of cotton fiber when the power density of UV was 100 W/em. And the surface morphology, degree of polymerization, mechanical properties, thermal stability and whiteness of the cotton fabric were discussed. The results indicated that the increase of irradiation time could lead to aggravation of damages in structure and properties of the cotton fiber. When the cotton fabric was irradiated for 30 s under UV, surface of the cotton fiber was etched and surface roughness of fiber increased. During the initial stage of cracking, the weight loss rate of the cotton fiber showed slightly increased, and the temperature at the largest weight loss rate of the irradiated cotton fiber was decreased by 8 ~C , which suggested that the thermal stability was reduced; and the whiteness of cotton fabric was dropped by 7% and cotton fabric became yellow. The covalent bonds C--C and C--O of cellulose were opened and the breaking strength in warp and weft directions of the cotton fabric was reduced by 21% and 10% , respectively. The degree of polymerization of the cotton fiber was decreased from 692 to 140. Damages in structure and properties of cotton fiber will become more serious as the irradiation time further increases.