Increasing chemisorbed silane coupling agents in surface‐treated layer of silica particles

Abstract

In the surface treated inorganic particles with silane coupling agent (SCA), chemisorbed and physisorbed molecules are present in the treated layer. Increasing the amount of chemisorption by increasing the molecular weight of SCAs was investigated. Oligomers formed via self‐condensation during storage more than 10 days at room temperature for 3‐methacryloxypropyltrimethoxysilane‐treated silica particles. Monomeric SCA evaporates easily by heating. The oligomers restrict evaporation, and heating increases the chemisorption. The influence of molecular weight of SCA was investigated. In the case of amino group, the amount of chemisorbed was greater for aminoethylaminooctyltrimethoxysilane with high molecular weight than for 3‐aminopropyltriethoxysilane. For SCAs with hydrocarbon chains, the amount of chemisorption was lower for both low molecular weight molecules and decyltrimethoxysilane (D) with a high molecular weight. For fluorocarbon chains, the amount of chemisorption was lower for low molecular weight molecules, whereas it increased significantly by heating for high molecular weight type of 1H,1H,2H,2H‐heptadecafluorodecyltriethoxysilane (F). Wide‐angle X‐ray diffraction analysis of F‐treated silica particles showed that the fluorocarbon chains formed an ordered structure. There was no such indication for the D‐treated system. This ordered structure seems to influence on higher chemisorption for F‐treated systems.

Effect of Calcination Temperature on the Phase Composition, Morphology, and Thermal Properties of ZrO2 and Al2O3 Modified with APTES (3-aminopropyltriethoxysilane)

“…In the final range above 500 • C, the dehydroxylation of residual ZrOH groups occured. Loss (IV) is associated with the dehydroxylation of grafted APTES species [32][33][34]. For alumina, the curve has a similar shape, but the thermal decomposition is more linear without several stages.…”

Improvement of coagulating strength and toughness of alkoxysilanes for conservation of cultural heritage

“…The evaporation of OLIs was smallest, because of higher molecular weight. In our previous report, 24 the amount of evaporation below 100°C decreased with progression of polycondensation of MPTMOS during the TG measurement.…”

“…They observed flash evaporation of physisorbed MPTMOS at 250°C and thermal decomposition of chemisorbed MPTMOS at 600°C. In our previous study, 24 TG of styrene monomer and polystyrene (PS) with various M w was measured. The evaporation of styrene monomer was completed below 100°C.…”

“…The spin–spin ( T 2 ) relaxation time obtained by measurement of the free induction decay (FID) curve is dependent on the molecular mobility: longer relaxation times indicate a more flexible polymer chain. In this study, the FID curve obtained was converted into the relaxation spectrum, H (τ) as follows 24 : the FID curve was normalized (i.e., the signal intensity for a relaxation time of zero was set to a constant value), and the first derivative of the normalized FID curve was obtained. The resultant H (τ) was plotted on a logarithmic time axis.…”

“…We clarified that the amounts of these four sorts can be estimated by the thermogravimetric analysis (TG) of SCA-treated silica particles before and after washing with a good solvent of SCA. 24 Above mentioned previously obtained our results were utilized for this research.…”