Thermal Mechanical Properties of Chemically Bonded Epoxy-Silica Hybrids
Chemically bonded epoxy-silica hybrids were prepared by curing the resin diglycidyl ether of bisphenol-A (DEGBA) by a gradual replacement of polyoxypropylenediamine (JeffamineD-400) with γ-aminopropyl-triethoxysilane (APrTS) which was used also as silica developer in the matrix by the sol-gel processing. Surface characteristics of the hybrid films were studied by atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). Thermal mechanical properties were studied by dynamic mechanical thermal analysis (DMTA), tensile and thermogravimetric analyses. A comparison of this work with the epoxy hybrids prepared under similar conditions but using different silane i.e., aminophenyl-trimethoxysilane (APhTS) enabled us to see the effect of interface provided by the coupling agent on the resulting properties. The stiffer phenyl interface between the epoxy matrix and the silica network in APhTS gave relatively large damping in the tan δ curves, higher increase in the modulus, tensile strength and glass transition temperature (Tg) and more reduction in the coefficient of thermal expansion in comparison to propyl group from APrTS.
Volume 106, May 2017, Pages 137–144