Shigeoki Nishimura

Surface Treatment of Silica Gels with Acetone- or Hexane-Solution of Alcohols or Phenols with Some Functional Groups and the Chemical Nature of their Surface Groups

The surface of silica gel was treated in an autoclave by the solution of alcohol or phenol with some functional groups in hexane or acetone, and their surface properties were investigated by determining their preferential dispersion into the media consisting of two immiscible components such as n-hexane and water. Furthermore, the identification of the surface groups and their thermal and chemical natures were examined through the infra-red spectra, differential thermal analysis (DTA), thermogravimetry (TGA) and qualitative analysis.The conclusions obtained are as follows: (1) The silica gels treated by diethylene glycol, 3-chloropropanol, phenol, or salicylic acid were hydrophilic whereas the ones treated by o-, m-, or p-cresol and hydroxybenzol were hydrophobic (lipophilic). (2) The characteristic absorptions due to alcoxy or phenoxy groups were observed in the infra-red spectra of the surface-treated silica gels. Since the intensity of the absorption at 950cm-1 due to bending vibration of Si-OH was almost the same for both the untreated and phenol-treated silica gels, it is still questionable whether silanol combines chemically with phenol or not. (3) DTA showed the exothermic due to dissociation and oxidation of the surface groups at 250°C, which is higher than the normal boiling point, and the remarkable exothermic due to oxidation of deposited carbon. Therefore, the surface groups are considered to combine with silanol chemically, except phenol. (4) These surface groups are confirmed to be alcoxy or phenoxy, since they were dissolved into boiling water or boiling dil. H2SO4 and, furthermore, from the qualitative analysis of dissolved solution, they were confirmed being alcohol or phenol used in this study.

Studies on the Surface Properties of the Organophilic Silica Gels through the Adsorption of Various Kinds of Vapors and the Heat of Immersion

The surface properties of the organophilic silica gels were investigated by the adsorption of argon at 77°K, of water vapour at 288°K and of n-heptane at 273°K and the heat of immegions of water and n-heptane, respectively, on the samples which the native silica gels were treated by methanol, ethanol, butanol, pentanol, hexanol, octanol, decanol, dodecanol and tetradecanol. The following results were confirmed:(1) Since the BET surface area of argon and of water on the native silica gel showed good agreement, and the one of argon on the activated carbon agreed with the one of n-heptane, the argon molecule could be adsorbed on both the organophilic and the hydrophilic surface.(2) The argon surface areas on the surface-treated samples showed remarkable decrease, increasing the carbon chain of alcohol. The water surface area showed remarkable decrease in comparison with the argon surface area on each sample.(3) The surface area from argon adsorption on the surface-treated silica gels showed the sum of the surface areas from water and from n-heptane, respectively.(4) The heat of immersion in water and n-heptane on the surface-treated silica gels were well-explained by using the respective surface areas from water and n-heptane.

Rate Processes on the non-Newtonian Flow of the Polymer Solutions

ポリスチレン,ポリイソプレンの非Newton流動曲線にRee-Eyring流動式を適応し,Newton,非Newton流動項を分離して求めた。Newton,非Newton流動項の分子量依存性は従来の見解と一致する。極限粘度は濃度依存性だけから求められるものには非Newton項を含む可能性のあることが認められたe。Newton流動項の1/c(X1β1/α1η0)=aβ1/a1ηoからaを球状粒子として見つもり求められるβ1/α1ηoは濃度,分子量に関せず一定である。したがって非Newton流動単位を棒状剛体粒子としてその大きさを見つもり,長さと半径の比が10倍程度で半径が100A程度の棒または紐状単位であろうごとが認められた。これから非Newton流動単位はこれらの紐状単位が相互にからみ合うことにより構成されているのであろうと推論された。

Adsorption on the Solid from the Imperfect Solutions

不全性をもつ溶液からの液相吸着力減分分子の大きさが等しい場合 (Regular Solution) ,成分分子の大きさが異なる場合について検討された。見かけの吸着等温線はx1の小さい範囲では正,大きな範囲では負の見かけの吸着量を示す。このような傾向の等温線は溶液内での成分分子間相互作用を考慮しないときにはえられない。実験結果への適応ではよい一致が認められ,こ求れからめられる表面積は溶質,溶媒分子の単一成分蒸気吸着で求められるBET表面積値と合理的な一致を示す。さらに分子の大きさの相違を考慮した詳細な検討は微粉体の空孔度についての知見を与えるであろうことが認められた。