The thickening mechanism of thickeners used in esters is due to the formation of homologues, and the mechanism of alkanolamides is that esters are mainly used in surfactant aqueous solution systems. Since there are unsulfated fatty alcohol ethoxylates in AES, the product thickening is poor when the homologues are wider, and the greater the thickening can be obtained. When interacting with anionic surfactant micelles, (pyrrolidone) alkanolamides have the potential hazard of producing carcinogenic nitrosamines when made into cosmetics to form non-Newtonian fluids. Various alkanolamides have great differences in performance, and they are also different when used alone and in combination. Some articles report the thickening and foaming properties of different alkanolamides.
There are free amines in the impurities of alkanolamides, which are potential sources of nitrosamines. In the formulation of fatty alcohol polyoxyethylene ether sulfate (AES) as the main active ingredient, ethers can generally be adjusted to a suitable viscosity using only inorganic salts. It has made a significant contribution to the thickening of surfactant solutions.
(Pyrrolidone) In-depth research has found that it works best when the average degree of ethoxylation is about 3EO or 10EO. In addition, the thickening of fatty alcohol ethoxylates is closely related to the distribution width of unreacted alcohols and homologues contained in the products. Recently, PEG-8PPG-3 diisostearate, PEG-90 diisostearate and PEG-8PPG-3 dilaurate have been reported abroad. This type of thickener belongs to non-ionic thickeners. (Pyrrolidone) This type of thickener is not easy to hydrolyze and has stable viscosity in a wide pH and temperature range. Currently, PEG-150 distearate is commonly used. Esters used as thickeners have the properties of some polymer compounds. A three-dimensional hydration network is formed in the aqueous phase, thereby incorporating surfactant micelles. In addition to being used as thickeners in cosmetics, this type of compound can also be used as an emollient and moisturizer.
Amine oxide is a polar non-ionic surfactant, which is characterized by: in aqueous solution, due to the different pH values of the solution, it shows non-ionic properties and can also show strong ionic properties. Under neutral or alkaline conditions, that is, when the pH is greater than or equal to 7, amine oxide exists in aqueous solution as a non-ionized hydrate, showing non-ionicity. In acidic solution, it shows weak cationicity. When the solution pH is less than 3, amine oxide is cationic, so it can be well compatible with cationic, anionic, nonionic and zwitterionic surfactants under different conditions and show synergistic effects. (Pyrrolidone) amine oxide is an effective thickener. When the pH is 6.4-7.5, alkyl dimethyl amine oxide can make the viscosity of the compound reach 13.5Pa.s-18Pa.s, while alkyl amide propyl dimethyl amine oxide can make the viscosity of the compound reach 34Pa.s-49Pa.s. The latter will not increase viscosity even if salt is added.
