应用光谱法研究紫外光诱发的纤维素硝酸酯的降解作用

STUDIES ON THE UV LIGHT INDUCED DERGADA- TION OF CELLULOSE NITRATE BY THE SPECTROMETRY

本文应用紫外-可见光谱和富里叶红外光谱仪,进行纤维素硝酸酯光降解作用的研究。光谱分析及化学测试所获得的结果,充分证明了在紫外光的照射下,纤维素硝酸酯发生了脱硝、解聚及交联作用。而且有证据表明,氧是交联反应的一个必要因素。随着光照时间的延长,交联结构的破坏,从而引起纤维素硝酸酯的严重降解。实验还表明,光照初期,Fe^(+3)的存在,有利于纤维素硝酸酯的光稳定作用。此外,本文也论述了纤维素硝酸酯的一条可能的降解路线。

Some aspects of UV light induced degradation of cellulose nitrate films have been evaluated by spectrometry such as UV, FTIR spectros-copies combined with chemical measurements. The results obtained from above methods demonstrated the light sensitivity of cellulose nitrate films with or without the presence of Fe+3 ions. Denitration, depolymerization and crosslinking reactions took place during the irradiation of cellulose nitrate films. The outstanding feature of the present work comparing with other investigations was the observation of crosslinking reaction when the films were irradiated in air. It was evident that oxygen was a prerequisite element for the occurrence of the crosslinking reaction, and the cr'oss-linked structure comprised oxygen and nitrate group. The significant destruction of crosslinked structure and catastrophic degradation of cellulose nitrate films were induced by the prolonged irradiation of UV light. It was interesting to note that Fe+3 ions were favourable to relieving the degradation of cellulose nitrate. One of possible pathways for photodegradation of cellulose nitrate has been discussed.