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Bulk Concentration Effects on the Structure and Orientation of Adsorbed Silane on the Surface of Nanosized SiO 2 Particles
Author(s) -
Hsiang HsingI.,
Chen ChiYu
Publication year - 2008
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2007.02113.x
Subject(s) - silanol , silane , adsorption , fourier transform infrared spectroscopy , molecule , chemical engineering , materials science , silicon , infrared spectroscopy , chemistry , composite material , organic chemistry , catalysis , engineering
In this study, the concentration effects of 3‐methacryloxypropyltrimethoxysilane (MEMO) on the surface coverage extent, orientation, and structures of MEMO silane grafted onto the surface of SiO 2 particles are investigated using Fourier transform infrared (FTIR) and 29 Si‐NMR spectroscopy. The MEMO silane concentration effects on the rheological behaviors of the SiO 2 particles–1,6‐hexanedioldiacrylate (HDDA) suspensions are discussed in terms of the surface coverage extent and the MEMO silane structures grafted onto the surface of SiO 2 particles. At low MEMO concentrations, many free silanol SiOH groups were observed for the MEMO grafted onto the SiO 2 surface and the adsorbed MEMO molecules tended to orient parallel to the SiO 2 surface due to the hydrogen bonding of the MEMO‐carbonyl and the hydroxyl group of the oxides. At high MEMO concentrations, the condensation reactions between neighboring grafted MEMO molecules result in the predominance of a T 2 and T 3 silicon atom structure and complete coverage of the SiO 2 surface by the grafted MEMO. The enhanced steric hindrance and compatibility between the MEMO‐modified SiO 2 particles and HDDA monomer, which originate from the complete coverage of the SiO 2 surface by MEMO silane and a higher proportion of free carbonyl groups on the grafted MEMO, may improve the dispersibility of nanosized SiO 2 in acrylate suspensions.