基于氮氧自由基荧光前体的耐辐射硅橡胶及其早期老化监测研究

硅橡胶在国防军工和航天领域应用广泛，但在多因素耦合γ辐射场中容易老化，较低剂量下关键性能就可能急剧的劣化而失效，严重降低了核能设施和航天装备的服役寿命和安全可靠性。因此，提高硅橡胶的耐辐射性和早期老化的监测灵敏性十分迫切。本项目探索利用氮氧自由基荧光前体（PFN）构筑耐辐射硅橡胶复合材料的方法。开展剂量率、温度、气氛和应力耦合γ辐射老化实验模拟材料真实服役老化环境。结合实验表征和理论计算揭示多因素耦合条件下含稠环的PFN增强硅橡胶耐辐射性和调控交联网络结构与辐解释气行为的可行性与分子机理。基于PFN加合物的荧光特性：建立硅橡胶辐射老化程度快速灵敏监测的方法，获得荧光特性指标与多尺度老化指标的定量对应关系，实现多因素耦合条件下硅橡胶早期辐射老化程度-微观结构-宏观性能-可靠性关系的快速构建。本项目有望为提高硅橡胶材料的耐辐射性、延长服役寿命和解决早期辐射老化监测瓶颈问题提供新策略和理论依据。

Polysiloxane rubber materials (PRM) are extensively used in the fields of national defense and military as well as aerospace industry. PRM are prone to degrade while they are exposed to γ radiation field coupled with multiple aging factors. To make things worse, the failure of PRM can happen even low dose exposure is given to it, which is due to the sharp deterioration of critical properties. The aging of PRM seriously shortens the service lifetime and impairs the safe reliability of facilities and equipment in the nuclear electrical power plants and aerospace industry like space craft, rocket and satellite. Hence, there is urgent need to improve the radiation resistance of PRM and the detection sensitivity of the early-stage radiolytic aging. This project will explore the method for the preparation of high-performance and radiation-resistant polysiloxane rubber composite (PRC) by incorporation of profluorescent nitroxide (PFN). To simulate the true service and aging environment of PRC, aging experiments of PRC in γ radiation field coupled with dose rate, temperature, atmosphere and stress will be carried out. Based on the experimental characterizations and theoretical calculation, PRC subjected to multiple aging factors will be studied. It is to be verified whether PFN with fused ring has the ability to enhance the radiation resistance and tunes the cross-linking network and outgassing behaviors of PRC. Moreover, the underlying molecular mechanisms will be unveiled. On grounds of the fluorescent characteristics of the PFN adducts, the method to quickly and sensitively detect the aging degree of PRC will be elaborated. The quantitative relationship between fluorescent characteristic indicators and multi-scale aging indicators will be established. It can be achieved to rapidly construct the relation between early-stage aging degree, micro-structures, macro-properties and service reliability. This project is aimed to provide new strategy and theoretical basis for improving the radiation resistance, prolonging the service lifetime and solving the bottleneck problems of PRC during the early-stage radiolysis.