Synthesis,characterization, and thermo mechanical properties of siloxane‐modified epoxy‐based nano composite

In this study, polymer hybrid composites were synthesized by sol‐gel process. 3‐Amino‐propyltrimethoxysilane APTMS)/γ‐Glycidoxypropyl trimethoxy‐silane (GPTMS); (4, 4′‐Methylene‐dianiline (DDM)] and 1,4‐Bis(trimethoxysilylethyl) benzene (BTB) were added to DGEBA type epoxy resin for anticipated to exhibit excellent thermal stability. Boron trifluoride monoethylamine (BF₃MEA) was used as catalyst. The structure of nanocomposites was characterized by attenuated total reflectance (ATR) and solid‐state ²⁹Si NMR which suggest EP‐APTMS‐BTB/EP‐GPTMS‐BTB possesses T³; T¹–T⁰, and T¹ structures when the BTB content was lower than 10 wt % and higher 20 wt %, respectively. BF₃MEA was proved to be an effective catalyst for the sol‐gel reaction of APTMS, but it could not promote for GPTMS. From TEM microphotographs, EP‐APTMS‐BTB (10 wt %) possesses a dense inorganic structure (particle size around 5–15 nm) compare with the loose inorganic structure of EP‐GPTM‐/BTB (10 wt %). DSC, TGA were use to analyze the thermal properties of the nanocomposites and DMA was used to analyze the dynamic mechanical properties of hybrid composites. The T_gs of all nanocomposites decreased with the increasing BTB content. A system with BTB content lower than 10 wt % showed good dynamic mechanical property and thermal stability (Td₅ increased from 336°C to 371°C, char yield increased from 27.4 to 30.2%). The structure of inorganic network affects the Td₅ and dynamic mechanical properties of composite. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40984.