B_4C_P/PI聚酰亚胺复合薄膜耐高温及热中子辐照屏蔽性能研究

以耐高温型聚酰亚胺为基体,微米碳化硼(B_4C)为热中子吸收剂,采用粉体表面改性及超声湿混-热亚胺化成膜工艺成功制备了一系列B_4CP/PI聚酰亚胺复合薄膜,重点探讨了不同B_4C含量条件下复合薄膜的耐热性能和力学性能以及不同B_4C含量、不同复合薄膜厚度条件下复合材料的热中子屏蔽性能。研究表明:采用上述工艺,B_4C功能粒子在聚酰亚胺基体中可均匀分散;B_4CP/PI复合薄膜的耐热性随B_4C含量的增加显著提高,力学性能则呈相反趋势;所制备的B_4CP/PI复合薄膜表现出优异的热中子屏蔽性能,中子透射率I/I0随复合薄膜厚度增加及B_4C含量增加呈指数变化规律。据此,可通过材料结构设计,满足不同领域对该类耐高温中子防护材料的应用需求。

Thermal Neutron Radiation Shielding and Thermal Properties of B4Cp/PI Polyimide Composite Films

B4Cp/PI polyimide composite films with different powder contents and thicknesses were prepared by particle surface modification and wet mixing machinery-thermal imidization method,using high temperature polyimide as matrix and micro-sized boron carbide (B4C) as thermal neutron absorption material.The thermal neutron radiation shielding property,thermal stability and mechanical property of B4Cp/PI polyimide composite films were mainly discussed in this paper.It is shown that the micro-sized B4C functional particles can be well dispersed in PMDA-ODA polyimide matrix,and the thermal stability of B4Cp/PI polyimide composite films are significantly improved with the increase of B4C content.However,the mechanical properties of the composite films present the opposite trend;meanwhile,the B4Cp/PI polyimide composite films exhibit excellent thermal neutron radiation shielding properties,and the neutron permeability I/I0 presents exponential relationship with the increasing thickness of composite and B4C filler particle content.Therefore,through structural design of the materials,the applications requirements in different fields for materials with high temperature resistant and thermal neutron radiation shielding properties can be met.