Abstract:With the development of nuclear power, extreme environment raised higher requirements for insulation parts. Fiberglass reinforced silicone resin (FRSR) is widely used in high-temperature and electromagnetic working environments due to its excellent physical and chemical properties. In order to improve the curing degree of silicone resin and ensure that the product performance matches material characteristics. The yoke coil bobbin of the control rod drive mechanism (CRDM) in the pressurized water reactor (PWR) nuclear power plant was used as compression-molded product of FRSR. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were used to analyze the curing thermal behavior of silicone resin molding compounds and optimized the compression process parameters of the bobbin. The thermal stability and mechanical properties were analyzed by TGA and tensile tests, and the effect of post-curing parameters on bobbin performance was studied. Experimental results reveal that, compared with normal temperature, the coil bobbin of post-curing at 175 ℃ for 24 h has the greatest increase of tensile strength, reaching 122% and the mass fraction of thermal mass loss is the least, reducing 82.25%. The weightlessness curing and thermal oxidative degradation of silicone resin affect the performance of the product. The optimal process parameters for compression molding yoke coil bobbins are molding temperature of 130 °C, molding pressure of 50 MPa, pressure holding time of 10 min, the post-curing temperature of 175 °C, and post-curing time of 24 h. The molded product can pass the thermal aging performance test verification of the nuclear power unit.