电子辐照聚酰亚胺薄膜力学性能演化机理研究

Mechanical property evolution mechanism of polyimide film under electron irradiation

利用空间综合辐照试验系统和X射线光电子能谱分析(XPS)、热重等分析测试对空间电子辐射环境下聚酰亚胺薄膜力学性能演化及机理进行了研究。研究发现,聚酰亚胺薄膜的拉力、抗拉强度和断裂伸长率随着电子辐照注量的增加先增加而后指数减小。由热重分析可知,电子辐照可引起聚酰亚胺薄膜的失重温度显著降低,在以失重10%作为判据的条件下,其失重温度由595℃下降为583℃。由XPS分析可知,电子辐照诱发聚酰亚胺薄膜化学价键的断裂和交联,在电子辐照初期,C—N键的断裂及引发的交联是导致力学性能增加的主要原因,而随着辐照注量的增加,C=O双键、—N(CO)键的断裂、新的C—N键的形成以及N元素的析出是导致聚酰亚胺薄膜力学性能降低的主要原因。

The electron irradiation ground simulation test was conducted on the mechanical property of polyimide film,thermo gravimetric and X-ray Photoelectron Spectroscopy was used to analyze the evolution mechanism of polyimide film in different electron fluencies.It was found that the mechanical properties such as tensile force,tensile strength and rupture elongation of polyimide film increased firstly and then exponentially decreased.The corresponding initial decomposition temperature of the electronradiated polyimide film lowered from 595℃to 583℃for weight-loss ratio of 10%.From XPS analysis,it can be found that there were ruptures and crosslinks of chemical bonds in the polyimide film.In early stage of electron irradiation,the rupture of C—N bond and the following crosslink increased the mechanical properties of polyimide film;however,along with the increase of electron irradiation,the ruptures of C=O and—N(CO)bonds,formation of C—N bond,as well as release of N were the main factors for the decrease of mechanical properties of polyimide films.