Carbamate-functional, biobased surfactants derived from cardanol, carbon dioxide, and amino acids: Their synthesis and properties

Three biobased, CO2-consuming, and carbamate-groups-containing surfactants (CC-G, CC-T, CC-L) were synthesized separately by combination of Cardanol, CO2, Glycine sodium salt (G), Taurine sodium salt (T), and Lysine sodium salt (L). The chemical structures of CC-G, CC-T, CC-L were confirmed by H-1 NMR and IR spectra. Thermal properties of these surfactants were studied with TGA and DSC. Their critical micelle concentration (CMC) and surface tension at CMC (?CMC) in aqueous solution were obtained by surface tension and conductivity methods, respectively. The amount of excess concentration (G(max)) and the average occupied surface area (Amin) of three surfactants were calculated. Gmax of CC-G, CC-T and CC-L was 2.35 x 10(-7) mmol/m(2), 2.23 x 10(-7) mmol/ m(2), and 6.16 x 10(-7) mmol/m(2), separately. Amin of CC-G was 0.71 nm(2)/mmol, CC-T 0.74 nm(2)/mmol, CC-L 2.70 nm(2)/mmol. The Krafft point, emulsification, and foaming power of these surfactants were investigated as well. The Krafft points were 0 degrees C (CC-G), 5 degrees C (CC-T) and 20 degrees C (CC-T). For CC-G, the separa-tion time of 10 mL double distilled water (DDW) was 43 min, CC-T 40 min, and CC-L 37 min. It was inferred from the calculated packing parameters that shape of the micelle of CC-G, CC-T were cylindrical in aqueous media, while CC-L was spheroidal in aqueous media.