Kang, S Hong, SI Choe, CR Park, M Rim, S Kim, J 2024-01-21T12:45:42Z 2024-01-21T12:45:42Z 2021-09-05 2001-02 0032-3861 https://pubs.kist.re.kr/handle/201004/140752 To investigate the interfacial effect on properties of epoxy composites, uniform sized silica particles (S) were synthesized by sol-gel reaction and then modified either by substituting surface silanol groups into epoxide ring (S-epoxide), amine (S-NH2) or isocyanate (S-NCO) groups or by calcinating them to remove surface silanol groups (CS). The modified particles are identified by infrared and raman spectroscopy, differential scanning calorimetry (DSC), and particle size analyzer. It has been found that surface modified particles can be chemically reacted with epoxy matrix, which is confirmed by exothermic peaks in DSC thermograms. In scanning electron micrographs of fractured composites, it is observed that the particle dispersion and interface are considerably affected by functional groups of fillers. Weak interfaces and aggregation of particles are observed for composites filled with CS or S-NCO. However, the aggregation of fillers is highly suppressed in composites filled with S-epoxide and S-NH2 particles. Generally, the coefficients of thermal expansion (CTE) of composites are reduced with an increase of filler contents. Moreover, composites with strong interface exhibit an additional reduction of CTEs. Composites with weak interface show essentially no change in glass transition temperature (T-g) and damping with filler contents, while composites with strong interface show an increase of T-g and a decrease of damping with filler content. (C) 2000 Elsevier Science Ltd. All rights reserved. English ELSEVIER SCI LTD DYNAMIC-MECHANICAL-PROPERTIES SILICA PARTICLES POLYMERS RESINS STRESS SIZE Preparation and characterization of epoxy composites filled with functionalized nanosilica particles obtained via sol-gel process Article 10.1016/S0032-3861(00)00392-X 1 POLYMER, v.42, no.3, pp.879 - 887 POLYMER 42 3 879 887 scie scopus 000089962500004 2-s2.0-0001677571 Polymer Science Polymer Science Article DYNAMIC-MECHANICAL-PROPERTIES SILICA PARTICLES POLYMERS RESINS STRESS SIZE epoxy composites silica sol-gel reaction