Epoxy/Silica Nanohybrids or Nanocomposites: Atomic Force Microscopy and X-ray Photoelectron Spectroscopy Investigation of the Processing-Structure-Property Relationships

摘要

The structural and morphological features influencing the glass transition temperature of epoxy/silica nanohybrid and nanocomposite materials containing 25-30phr of nanoscale silica phases are discussed in this letter to answer the questions related to the processing-structure-property relationships. X-ray photoelectron spectroscopy and atomic force microscopy are used to study the surface chemical structure and morphology of epoxy/silica nanohybrids and nanocomposites. Nanohybrids are synthesized via in situ sol-gel process, while the respective nanocomposites are prepared by mechanical blending of preformed silica nanoparticles into epoxy resin. Differential scanning calorimetry is used to determine glass transition temperature of different materials. The surface analytical characterizations reveal that in situ sol-gel process is more suitable for producing organic-inorganic hybrid materials with superior glass transition temperature owing to the achievement of stronger interfacial compatibility and greater crosslink density. A number of other factors affecting glass transition temperature are explored and discussed with reference to surface chemistry, microstructure, and morphology of epoxy/silica nanohybrids and nanocomposites, respectively.