Toshiaki Ogasawara

Polymerization process of the silane coupling agent 3-aminopropyltriethoxy silane – 1H NMR spectra and kinetics of ethanol release

Abstract In the 3-aminopropyltriethoxy silane–deuterated ethanol–H 2 O system, the rate of release of ethanol from the ethoxy groups, a reaction which occurs during the condensation process, has been followed by use of 1 H NMR spectroscopy at different temperatures. Two separate reaction processes have been identified, and values of the reaction rate constants and thermodynamic parameters ( E a , Δ H ‡ and Δ S ‡ ) have been calculated.

2D gel permeation chromatography (2D GPC) correlation studies of the growth process for perfluoro-octyltriethoxysilane polymer aggregates

A novel analytical technique, two-dimensional correlation gel permeation chromatography (2D correlation GPC), has been used to elucidate intricate details of the two-step (I and II) polymerization of 1H,1H,2H,2H-perfluoro-octyltriethoxysilane (PFOTES) catalyzed by 0.5, 1.0 and 2.0 M HCl·H2O over a time period of 600–14 400 s. The 2D GPC correlation results demonstrate that each elution band (particularly, in step II) consists of two (reactive and nonreactive) components and that a higher HCl concentration enhances the correlation of the reactive component with other bands. It is suggested that rapid growth of the polymeric aggregates in step II may be caused by the appearance of these reactive components.

Raman scattering study of ‘polyaminopropylsiloxane’ aggregates and conformational change of aminopropylsilyl segments

Abstract The Raman spectra of polyaminopropylsilane in the solid and gel phases and in aqueous solution have been examined in detail. It has been confirmed that a conformational change of the aminopropyl segments occurs, which depends on both concentration and pH, and that there is preferential stabilization of the bent or cyclic structures of the aminopropyl segments resulting from the NH 2 → + NH 3 conversion at lower concentration and lower pH values.

Application of generalized two-dimensional correlation theory to gel permeation chromatographic analysis

This report demonstrates the promising potential for the application of generalized two-dimensional correlation analysis to time dependent GPC elution profiles, in analysis of complex dynamic variations in the sol–gel polymerization process.

Raman and IR studies of the interaction between aerosol OT and polyaminopropylsiloxane

Abstract The infrared and Raman spectra of the areosol-OT (AOT)–polyaminopropylsiloxane (poly APS) system have been examined in detail. The results provided ample evidence that there exists a strong hydrogen-bonding network between AOT-carbonyl and poly APS-NH2 groups.

Two-dimensional correlation gel permeation chromatography (2D correlation GPC) study of the sol–gel polymerization of octyltriethoxysilane. HCl-concentration dependence

Two-dimensional correlation gel permeation chromatography (2D GPC) was used to elucidate intricate details of the initial ten minutes of the sol–gel transition of n-octyltriethoxysilane (OTES), catalysed by 0.5 and 2.0 M HCl·H 2 O. The results demonstrate that the features of 2D GPC correlation spectra directly reflect the dynamic variation of reactions or interactions present during the polymerization process.

Time-resolved near IR and 2D-correlation spectroscopic studies of the polymerization process of 3-aminopropyltriethoxysilane

The polymerization behavior of 3-aminopropyltriethoxysilane, a process initiated by water molecules, has been examined using time-resolved Near IR and 2D Near IR correlation spectra. In the time-resolved Near IR spectra, the bands at 5184 and 5300 cm−1 have been assigned to water molecules and the silanol (SiOH) group, respectively. The intensities of the two Near IR bands decrease markedly as the reaction proceeds, indicating that water molecules and the SiOH groups are utilized in hydrolysis of the ethoxy groups and formation of a siloxane bond, respectively. It has also been found that this polymerization process is distinctly reflected in the 2D Near IR correlation spectra.