Synthesis and Foaming Performance of Lauramidopropyl Betaine Derivate Surfactants

The ampholytic surfactant Lauramidopropyl betaine (LAB) is a multifunctional amphoteric surfactant, which is widely used in washing formulations and is the main component of many softeners and detergent formulations. It has the advantages of less irritation to skin, mild performance and easy biodegradability. It is superior to other amphoteric surfactants. In this paper, new surfactants were synthesized by using LAB as the main component and the molar ratios of LAB to formaldehyde were 1:1, 1:2, 1:3 and 1:4, respectively. The new functional group hydroxymethyl was introduced into the LAB, and the effect of hydroxymethyl on the properties of raw materials was discussed. And the surface properties were studied, including high temperature resistance, methanol resistance and salt resistance. The results showed that the high temperature resistance of R2 is better below 50 °C, R0 has better high temperature resistance above 50 °C; In the aspect of methanol resistance, the methanol resistance of R4 is better at 10% and 20% methanol content; The effect of R0 is better in salt resistance. Finally, it can be concluded that the introduction of methylol groups improves the performance of the prepared new surfactants in certain properties.