Catalytic polyadditive polymerization of the system based on SIEL compound in the presence of the series of fillers was investigated. Silicon SIEL compounds find wide practical application in fiber, integrated optics, microelectronics, medical equipment, and etc.; the application of SIEL compounds as the basis for the creation of magneto-control composites is a new and perspective direction. The influence of the various fillers on the processes of compound catalytic vulcanization and on the properties of the obtained composites was studied. The influence of the additives on the polymerization rate, process activation energy, and composite physical-mechanical properties after heating at T ≤ 280°C was determined. During investigation of polymerization kinetics on a Brookfield rheometer in the system cone-and-plate in the area of 50–105°C, it was shown that the temperature dependence of the polymerization reaction rate is described by the Arrhenius equation, and activation energy characterizes the inhibiting influence of the additives. The thermostabilizing influence of magnetite additive on composite was defined, which allows to synthesize thermostable elastic composite materials with an operating temperature up to 280°C. The complex of the investigations promotes the optimization of the methods of production and operation of the composites based on SIEL compounds. Polymerization by the polyadditive technique is satisfactorily proceeded on a Pt-catalyst (Karstedt), coated on a polymer silicon support.