Synthesis of poly(methylphenylsiloxane)/phenylene‐silica hybrid material with interpenetrating networks and its performance as thermal resistant coating

In this study, poly(methylphenylsiloxane) (PMPS) and phenylene‐silica based hybrid material with interpenetrating networks was prepared by a two‐step sol–gel process. Firstly, in the presence of H₂SO₄, the phenylene‐silica was formed as sol particles with high branching degree by cohydrolysis and condensation of phenylene‐bridged monomer, tetraethoxysilane (TEOS), and hexamethyldisiloxane (MM). Then, the intermediate transformed into gel framework in polymer matrix using alkali catalyst, in order to produce a homogenous hybrid material with interpenetrating networks. The structure of prepared hybrid material was characterized by FTIR and NMR, suggesting that phenylene‐silica framework was imported into polymer matrix and the hybrid products have a much higher network chain density than neat PMPS. The thermogravimetric analysis (TGA) shows that the prepared materials start to degrade at around 490°C. The results of tensile test indicate that the typical PMPS/phenylene‐silica hybrid material has a tensile strength up to 26 MPa and demonstrate a certain degree of flexibility. An increase of phenylene content in phenylene‐silica particles tends to produce hybrid materials with improved thermal stability and tensile strength. The hybrid coating films after calcinating at 350 and 400°C for 2 h exhibit a good mechanical performance on adhesion, impact strength and flexibility. Electrochemical impedance spectroscopy (EIS) measurements show that the investigated films have an extremely high electric resistance (10¹⁰ Ohm·cm²) and a satisfied impermeability to 3.5 wt % sodium chloride solution. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013