γ和中子辐照作用下GFRP机械强度和热性能变迁及其微观机理研究

Glass fiber reinforced plastic (GFRP) with the character of high structural strength, high electrical insulation and high heat insulation is used as the raw material for the support equipment under the γ and neutron irradiation in the high-energy physics and nuclear physics experiments. Studies have shown that GFRP’s mechanical strength changed under the single γ or single neutron irradiation, so the structural strength of the supporting equipment was affected. Therefore, it is great scientific significant and practical valuable to carry out the research of the mechanical and thermal properties of GFRP in the combination irradiation environment of γ and neutron. The project will systematically study the dynamic change rules of GFRP performance under the condition of the different type and dose of γ and neutron irradiation, and the correspondence between the cross irradiation and the GFRP properties can be given. Then the interaction of γ irradiation and neutron irradiation on the GFRP properties will be elucidated when two types of irradiation affects together. By the means of observing the change of morphology and molecular structure of the material before and after irradiation, the reaction mechanism theory of internal structure of GFRP under the combination irradiation environment of γ and neutron can be built. A concept, the irradiation factor will be built and introduced to the existing strength equation, and then a theoretical model can be constructed to describe the relation between the type and dose of the irradiation and the GFRP mechanical strength. The results of the project will provide an important security for the structure of the GFRP supporting equipment in the irradiation environment, and offer a theoretical and technical support for developing and manufacturing GFRP of irradiation resistance in the future.

高强度、高电绝缘、高热绝缘玻璃纤维增强材料（GFRP）是高能物理和核物理实验等γ和中子共同辐照环境中支撑设备的重要原材料，其机械强度在单独γ或单独中子辐照下将发生变迁从而影响支撑设备的结构安全。因此，开展γ和中子共同辐照下GFRP机械强度和热性能变迁的研究具有重要科学意义和实用价值。本项目系统研究γ和中子辐照类型和剂量变化条件下GFRP性能的动态变化规律，给出交叉辐照与材料性能参数之间的对应关系，进而揭示共同辐照时两种辐照对材料性能的交互作用规律；通过观测辐照前后材料的微观形貌和分子结构变化，建立γ和中子联合辐照条件下GFRP内部结构反应机理理论构架；建立辐照因子概念，将其引入现有强度方程，构建适合γ和中子辐照条件的GFRP机械强度理论模型。预期项目研究成果能为辐照环境中GFRP装置的结构安全保障提供科学依据，为具有抗辐照性能GFRP材料的设计和制备提供理论和技术支撑。

玻璃纤维增强树脂基复合材料（GFRP）由于其良好的机械强度、热性能和电绝缘性能，为我国新一代北京正负电子对撞机（BEPC II）中束流管支撑法兰的备选材料。BEPC II在运行过程中，将对束流管及其支撑材料产生大量γ和中子辐照，作为一种复合材料，GFRP在辐照环境下将发生性能变迁，从而影响其设备的正常运行。本项目研究内容主要包括：.（1）研究辐照对GFRP机械性能的影响规律，构建GFRP疲劳寿命预测理论模型。静拉伸强度随γ辐照剂量的增加而下降，通过疲劳实验建立双参数疲劳寿命模型用于疲劳寿命预测。层间剪切强度随γ辐照剂量的升高而先降低后升高，而γ和中子混合辐照下GFRP的层间剪切强度和压缩强度均随着辐照剂量的增加而降低，并且随着辐照剂量的增大，下降幅度更为明显。.（2）给出辐照对GFRP热性能的影响规律。随着γ辐照剂量的增加，GFRP的热分解失重比降低，导热系数先减小后增加，热膨胀系数减小。分别利用普适积分法、Friedman法和 FWO法，以四种不同温度下的热分解数据为基础，计算在四种辐照剂量不同失重率情况下的活化能，发现活化能均随辐照剂量增加而增加。.（3）揭示辐照对GFRP的电绝缘性能的影响规律，建立辐照剂量与平均电阻率之间的理论模型。经20 kGy、100 kGy和200 kGy的γ辐照后，GFRP的体积电阻率分别增加了94.6%、183.5%和428.8%，电绝缘性能降低。同时，建立了平均电阻率与γ辐照剂量之间的理论模型。.（4）揭示引起GFRP机械性能和热性能变迁的微观机理。经SEM发现，辐照后的GFRP出现环氧树脂与玻璃纤维分离且碎片化的现象，环氧树脂的辐照降解反应强于辐照交联反应，玻璃纤维表面出现裂纹。红外光谱图表面，辐照后没有新的化学键生成，随着辐照剂量增加，分子链发生了大规模断裂。通过XPS研究发现，GFRP在辐照后发生了氧化反应。从微观结构变化解释了GFRP机械强度和热性能的变迁。.本课题为GFRP支撑设备在高能物理和核物理辐照环境下的安全运用提供重要科学依据，为具有抗辐照性能GFRP的设计和制备提供理论和技术支撑。