Preparation and properties of multi-branched cationic polyurethane surfactants

In order to study the structure control method and structure-activity relationship of multi-branched cationic polyurethane surfactants with multiple long alkyl chains, a series of multi-branched long-chain alkyl quaternary ammonium polyurethane surfactants (SC2, SC3 and SC4) were prepared from isophorone diisocyanate (IPDI), N-methyldiethanolamine, cetyl alcohol and bromine substituted alkanes. The structure of the product was confirmed by FTIR and 1HNMR. The critical surface tension (γCMC), Krafft point, foaming ability, emulsifying ability and salt tolerance were tested. The results showed that cationic polyurethane surfactant SC3 with three-branched long-chain alkyl groups was a mixture of cationic polyurethane surfactants SC2 with dihexadecyl group and cationic polyurethane surfactants SC4 with four hexadecyl groups. The γCMC values of SC2 and SC4 were 23.61 and 30.35 mN/m, the corresponding critical micelle concentrations (CMC) were 3.0×10-4 and 2.5×10-4 mol/L, and the corresponding Krafft points were 23 and 41 ℃. The products had high surface activity and good emulsification, foaming and salt tolerance. © 2022, Editorial Office of FINE CHEMICALS. All right reserved.