Radiation shielding composites based on polyimide and Bi 2 O 3 were synthesized. Surface and physical-mechanical properties of polyimide/Bi 2 O 3 composites were studied. Bi 2 O 3 particles were modified by polymethylphenylsiloxane for the uniform distribution of filler in composites. This paper presents data on the production of composites in two ways: hot- and cold-pressing. The hot-pressing method for the synthesis of composites is preferable compared to the cold-pressing method (the density increases by 10–12%, and the Vickers microhardness by 10–20%). The results show that the introduction of Bi 2 O 3 significantly increases the thermal stability of the composites. At 680 °C, a polymer composite containing 10 wt% Bi 2 O 3 retains 9.7% of its mass, and at 60 wt% Bi 2 O 3 , retains 58.4%. The radiation-protective characteristics of the composites with respect to gamma radiation were evaluated by experimental and theoretical methods. High radiation-protective characteristics of the composites have been established in the gamma-quanta energy range of 0.1–1 MeV.

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This paper presents data on the synthesis of composites based on polyimide and modified tungsten (IV) oxide (WO 2 ). The resulting, highly filled, polyimide/WO 2 composites were investigated by electron microscopy and thermal analysis in a gas environment of oxygen and argon. The maximum content of modified WO 2, in the studied composites, was 60 wt%. The introduction of WO 2 increases the thermal stability of the composites. For pure polyimide, the upper limit of the operating temperature is 507°C; for a composite with a content of 30 wt% WO 2 − 526°C, and for 60 wt% WO 2 − 554°C in a gas environment of Ar. The change in the physico-mechanical properties of highly filled polyimide composites was studied under the conditions of thermal cycling from −190°C to +200°C. The time of one cycle was 22 min. The thermal cycle was repeated 5, 10 and 20 times. The following parameters were determined: tensile strength, modulus of tensile elasticity and elongation under tension. The introduction of WO 2 slightly reduces the initial strength characteristics of the composites.

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