Study On Properties Of N-C_16/18-alkyl Polyethoxy Carboxylate

Alkyl polyethoxy carboxylates ?AEC? are a series of original anionic surfactants,which have shown significant applications incosmetics, petroleum industry, medicine and pesticides. As some mixed surfactant systems exhibit superior properties compared with individual component, the research of mixed surfactant systems has become an important part of the studies about surfactants. The physico-chemical properties of alkyl polyethoxy carboxylates containing 10 ethylene oxide group and a fatty chain of n-C16/18 (A_16-18EC)were investigated at first. Then, the surfactants of alkylethoxyglycosides ?AEG500E?,dodecyldimethylbenzylammonium chloride ?1227?, lauryltrimethylammonium chloride?1231?, didecyldimethylammonium chloride ?DDAC?, cocoamidopropyl betaine ?CAB?and alcohol polyoxyethylene ether sulfates ?AES? were choosen to mix with A_16-18EC to explore the physico-chemical properties of these mixed systems. The properties of the mixed surfactant systems were investigated by surface tension, wetting, foaming,emulsification and detergency measurements. The phase behavior of the mixed systems was also studied.?1? The values of CMC and ?cmc of A_16-18EC are 0.022 mmol/L and 37.58 mN/m,,respectively. The properties of emulsifying ability, foaming stability and detergency of A_16-18EC are excelent, but the wettability is poor. With the addition of A_16-18EC, the isotropic solution, gel and solid are observed in the binary phase diagram of A_16-18EC/H2O system.?2? For A_16-18EC/AEG500E mixed system, the synergism was found in surface tension, emulsifying, wetting and foaming properties. Micellar phase, lamellar phase and the coexisting phase of them were observed in the A_16-18EC/AEG500E/H2O diagram with the addition of A_16-18EC.?3? For A_16-18EC/1227 mixed system, the synergetic effects were all observed in surface tension, emulsifying and wetting properties. Micellar phase, lamellar phase and the coexisting phase of them were also observed in the A_16-18EC/1227/H2O diagram with the addition of A_16-18EC.?4? For A_16-18EC/1231 mixed system, the synergetic effects were showed in surface tension and wetting properties. With the addition of A_16-18EC in the A_16-18EC/1231/H2O diagram, micellar phase and lamellar phase were observed in order.?5? For A_16-18EC/DDAC mixed system, the synergetic effects were also found in surface tension .and wetting properties. The micellar phase and lamellar phase were observed sucessively with the addition of A_16-18EC in A_16-18EC/DDAC/H2O diagram?6? For A_16-18EC/CAB mixed system, the synergism was found in surface tension,emulsifying and wetting properties. The micellar phase and lamellar phase were also found in order with the addition of A_16-18EC in A_16-18EC/CAB/H2O diagram.?7? For A_16-18EC/AES mixed system, the synergism was found in surface tension only,the properties of emulsifying,wetting,detergency and foaming ability were not found synergetic effects. Micellar phase, lamellar phase and the coexisting phase of them were also observed in the A_16-18EC/AES/H2O diagram with the addition of A_16-18EC.