紫外线照射导致真丝绸黄变的机理

本文对真丝绸在紫外线照射下发生黄变的机理进行了初步探讨。研究结果表明:真丝绸受紫外线照射随受照时间的增加而白度降低;丝蛋白的肽链发生了断裂,组成氨基酸遭到不同程度的破坏,损失百分率大的是酪氨酸、苯丙氨酸、赖氨酸和组氨酸等;主要光解反应首先发生在非晶区内,进而向晶区扩展;丝纤维的热分解温度稍有降低,而热分解热焓则明显减小。同时,还发现织物水分的存在更能加速光解反应。

Studies on the Mechanism of Silk Yellowing by Ultraviolet Irradiation

Through studies made on the mechanism of silk yellowing by ultraviolet irradiation,it is shown:The whiteness of silk is reduced with the increase of the time of irradiation;the peptide chains of the fibroin are broken,and the composite amino acids are damaged to different degrees,of which TYR, PHE,HIS,etc.are highly damaged;the primary optical degradation occurs first in the amorphous region and then develops into the crystalline region; The temperature decrease in silk thermal decomposition is slight,but the enthalpy decrease is prominent;the existence of water in the fabric expedi- tes the yellowing process.