Abstract: 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 (FeSt3) and cerium stearate (CeSt4) 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 FeSt3 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% FeSt3. However, there was a drawback found in the early stage of irradiation, in which the starch-based material containing 0.3 wt% of FeSt3 exhibited a lower photoinitiation rate than that with 0.3 wt% of CeSt4.

Key words: photosensitizer;starch-based photodegradable polymer, iron stearate cerium stearate