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Interphase Effects in Dental Nanocomposites Investigated by Small-Angle Neutron Scattering



K S. Wilson, Andrew J. Allen, N Washburn, Joseph M. Antonucci


Small angle neutron scattering (SANS) was used to assess nanoparticle dispersion morphologies and nanoscale interphase characteristics in polymer composites containing four concentrations of silica nanoparticle fillers (10 %, 25 %, 45 %, and 60 % by mass fraction) silanized with varying mass ratios of 3-methacryloxypropyltrimethoxysilane (MPTMS) and octyltrimethylsilane (OTMS). MPTMS can covalently bond to the matrix and OTMS interacts with the matrix through weak dispersion forces. Interphases with high mass fractions of OTMS were fractally rough with fractal dimensions Ds = 2.19 0.06 up to Ds = 2.49 0.05.These interphase characteristics were associated with poor interfacial adhesion and the inferior mechanical properties of these composites. There was no observable trend in nanoparticle microstructures as a function of silane interphase composition for composites that contained 45 % or 60 % silanized silica by mass fraction. However, mean nearest-neighbor particle distances calculated for the 10 % and 25 % silica composites suggested that the nanoparticles treated with higher mass fractions of MPTMS relative to OTMS were slightly better dispersed than the OTMS-treated nanoparticles. These results suggested that covalent bonding of nanoparticles with the polymerized matrix was an effective strategy for preparing well-dispersed nanocomposites.


aggregation, dispersion, nanoparticle, silane, silica, thermoset composite


Wilson, K. , Allen, A. , Washburn, N. and Antonucci, J. (2007), Interphase Effects in Dental Nanocomposites Investigated by Small-Angle Neutron Scattering, Macromolecules, [online], (Accessed April 14, 2024)
Created April 6, 2007, Updated January 27, 2017