Preparation and characterization of hydroxyl-terminated polybutadiene graft ferrocene based composite

Butacene is a polymeric binder that incorporates ferrocenyl groups chemically bonded to the backbone of the hydroxyl-terminated polybutadiene (HTPB). Given the role of iron as an oxidation catalyst and its potential applications in the aerospace and aeronautics industries, it is important to design a desirable product with improved initial decomposition, increased thermal sensitivity, high thermal stability, and superior catalytic performance. To attain improved desired properties, without compromising the critical physical features of HTPB, herein, a one pot and cost effective synthesis method was employed for this purpose. Iron containing HTPB composite samples, containing 5, 10, 20, 35, and 50 wt% ferrocene, were synthesized through Friedel Crafts alkylation of ferrocene with HTPB while using AlCl3 as a Lewis acid catalyst. Ferrocene, serving as the source of iron to ensure minimal alteration in the microstructure of HTPB. Confirmation of the chemical structures, elemental composition, and surface morphology of the polymer and Fc-HTPB composite samples was achieved through Fourier transform infrared spectroscopy (FTIR), CHNS/O analysis, and scanning electron microscopy (SEM), respectively. Based on these results, it can be said that the desired composite samples are successfully fabricated. Physiochemical characterization, including tensile strength testing was conducted. Additionally, thermal properties such as thermal stability of the final product were studied through thermogravimetric analysis (TGA), Furthermore, rheological investigations, including viscosity, loss and gain moduli of HTPB and the newly synthesized composite samples (Fc-HTPB) were carried out. Based on the comprehensive physiochemical results obtained, it was observed that addition of ferrocene (Fc) to HTPB and also by changing the ratio of Fc/HTPB could enhance the desired physiochemical behaviour of the Fc-HTPB composite. This study also offers a potential pathway for proposing and recommending a composite formulation with enhanced cumulative properties for use as a catalyst to accelerate burning rates in future propellants.