| Co-Investigator(Kenkyū-buntansha) |
OHBA Kenkichi Lion Corporation, Div.of Reserch and Development, General Manager, 研究開発本部, 本部長
HIRAO Toshikazu Osaka University, Department of Applied Chemistry, Faculty of Engineering, Profe, 工学部, 教授 (90116088)
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| Research Abstract |
Bis-ammonium salt-type surfactants were newly synthesized. This kind of cationic surfactants have two lipophilic alkyl chains and two hydrophilic groups in a molecule, and are formally prepared by connecting two traditional mono-ammonium salts (to be denoted as monomer), which have one alkyl chain and one hydrophilic group, with a proper link. In the present research, the following results were obtained ; a) the bis-ammonium salt-type surfactants (dimer) have extremely low critical micelle concentration (CMC). For example, CMCs of dodecyl derivatives of dimer and trimer were 10^<-4> and 10^<-6> M,respectively, in contrast with 10^<-2> M of monomer. b) Their surface tension lowering ability is superior to that of monomer. c) Cationic surfactants have almost no foaming ability and practically no foam stability. On the other hand, dimer with a proper hydrophile-lipophile balance show extremely high foaming ability and foam stability, even superior to the anionic surfactants having the hig
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hest foam property. Cationic surfactans are usually utilized as a textile-softener, an antistatic agent, or a disinfectant, depending upon their adsorbing property on the solid surface. From the viewpoint of this property, the adsorbing property of dimer, trimer, and tetramer were examined and compared with that of monomer, expecting their high performance based on their multi-adsorption character on solid surface. Dimer adsorbed on the solid surface 5 times more than monomer, and trimer 8 times more, based on the number of ammonium groups adsorbed. Tetramer, however, adsorbed almost the same extent with dimer, maybe depending on the difficulty of close packing. In conclusion, 1) The connecting agent with high reaction rate was found out. 2) The correlation between the superior surface-active property of bis-ammonium salt-type surfactants and their structure was disclosed. 3) The correlation between adsorption property and oligomerization of the cationic surfactant was disclosed and the optimum structure was shown. Less
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