Study on electron beam cross-linked ethylene-tetrafluoroethylene copolymer-insulated cables for aerospace applications: Mechanical performance, crystallization kinetics, and fluoride precipitation

The cross-linking effects of cross-linked ethylene-tetrafluoroethylene copolymer (XETFE)-insulated cables at different electron beam radiation doses were analyzed in this paper. Evaluation of the mechanical performance of the cables revealed that the highest tensile and breaking elongation was achieved at a radiation dose of 8 × 10⁴ Gy and that XETFE had a good resistance to extreme electron beam irradiation. This is attributed to the cross-linking effects induced by electron beam irradiation, and this takes full advantage of the strength of molecular chain crosslink to each other. The crystallization kinetics of XETFE at different electron beam radiation doses were studied in detail in terms of the non-isothermal and isothermal crystallization processes. The results indicated that the crystallinity of the XETFE domain increased with an increase in the radiation dose as a result of heterogeneous nucleation. Moreover, the highest ΔE_a was obtained, indicating that XETFE absorbed some energy at a radiation dose of 8 × 10⁴ Gy. These kinetic parameters had help in carrying out a comprehensive evaluation of the performance of XETFE-insulated cables for aerospace applications. Moreover, the fluoride precipitation observed in this study indicated that upon electron beam irradiation, XETFE could internally produce hydrogen fluoride, which is corrosive to metals. Thus, optimizing the radiation dose was necessary to achieve the desired performance. We could believe that the improvement for properties of electron beam XETFE insulation cables would expand their range of applications in the aerospace field.