淀粉基壁材的光降解性能研究

Study on Photodegradable Properties of Starch-based Wall Materials of Microcapsules

随着航天科技的迅猛发展,地球近轨道的太空垃圾不断增多,因此考虑将微胶囊导入至航天器材料中,通过控制囊壁材料的光降解速率进而控制航天器材料降解时间。本文主要对以淀粉基为囊壁材料的光降解性能进行了初步研究,淀粉被用作基体,通过引入不同含量的硬脂酸铁(FeSt3)和硬脂酸铈(CeSt4)作为光敏剂来制备光降解聚合物。研究发现,淀粉本身具有一定的光降解性,但光敏剂的添加可以有效地促进淀粉的光降解,并且无论添加何种光敏剂,光敏剂质量分数为0.3%时光敏降解性能均较好;特别是经光照72h后,含有0.3%FeSt3的淀粉特性黏度和冲击强度分别降低67.64%和59.59%,羰基指数(CI)增加至17.68,受光降解作用影响作用最大,表明0.3%FeSt3实现了最佳光催化降解淀粉的性能;但是仍存在一定的缺陷,在光照早期阶段,0.3%FeSt3的光引发降解速率低于相同含量的CeSt4光引发降解速率。

With a rapid development of aerospace technology in recent years, there is a continuous increase in the amount of space debris in the near orbit of the earth. It is a time to consider the incorporation of some microcapsules into the spacecraft material so as to control the degradable time of the spacecraft materials by controlling the photodegradable rate of wall materials of microcapsules. In this work, we investigated the photodegradable performance of starch-based materials prepared with starch as a matrix and iron stearate (FeSt 3 ) and cerium stearate (CeSt 4 ) as photosensitizers. The results indicated that starch had certain photodegradability, and the addition of photosensitizers could effectively promote the photodegradation of starch. The photodegradable performance was optimum at the photosensitizer content of 0.3 wt% after 72 h irradiation. The starch-based material containing 0.3 wt% of FeSt 3 showed a decrease in intrinsic viscosity by 67.64 % and in impact strength by 59.59 %. The carbonyl index was found to rise up to 17.68, indicating a most significant influence by photodegradation. These results confirmed that the starch-based materials achieved the optimum photocatalytic degradation with the addition of 0.3 wt% FeSt 3 . However, there was a drawback found in the early stage of irradiation, in which the starch-based material containing 0.3 wt% of FeSt 3 exhibited a lower photoinitiation rate than that with 0.3 wt% of CeSt 4 .