Preparation And Performance Study Of Efficient Suspension System In Surfactant Solutio

In order to make functional daily products richer,functional solid particles represented by mica powder,pearlescent agent and flavor microcapsules can be added.However,the difference in density between the solid particles and the matrix solution makes it difficult to achieve long-term stable suspension of the solid particles.In order to solve this kind of problem,this paper investigates the existing polyacrylic acidbased suspension stabilizers and prepares new polysaccharide-based suspension stabilizers to investigate the rheological properties and suspension of solid particles in different surfactant systems(alcohol polyoxyethylene ether,AEO;fatty alcohol polyoxyethylene ether sodium sulfate,AES;didecyl dimethyl ammonium chloride,DDAC),the main conclusions are as follows:1.Firstly,the rheological properties of polyacrylic acid suspension stabilizers in surfactants and the suspension stability of solid particles were investigated.The results showed that linear polyacrylic acid hardly achieves stable suspension of solid particles in two surfactant solutions.While the branched acrylic acid shows better suspension stability to solid particles in the AEO system,with a yield stress of about 0.78 Pa for0.15wt% Carbomer 941(Mv=1.25 million)compounded with 20wt% AEO,which is higher than the yield stress of 0.04 Pa for Carbomer 940(Mv=4 million)compounded with AEO.The smaller molecular weight facilitates the full extension of the Carbomer chain in AEO.In addition,in the AES system,Carbomer has essentially no ability to suspend solid particles and the system behaves as a Newtonian fluid at high shear rates,losing the original shear thinning behaviour of the polymer.2.Since polyacrylic acid suspension stabilizers are only suitable for non-ionic surfactant systems,in order to further search for suspension stabilizers suitable for use in different surfactant systems,this paper suggests the construction of a threedimensional network structure using bacterial cellulose microgels as a base and its interactions with neutral water-soluble polymer hydroxypropylmethyl cellulose(HPMC).By the oxidation of TEMPO(2,2,6,6-tetramethylpiperidine-1-oxyl radical),the surface of bacterial cellulose microgels was nanofibrillated to different degrees and the effects of the nanofibrillation on the rheological properties of the compounding systems and the suspension properties of the solid particles were investigated.The results showed that the higher the degree of nanofibrillation on the surface of the bacterial cellulose microgels,the greater the yield stress and thixotropic ring of the system complexed with HPMC and AEO,with the yield stress increasing from 0.07 Pa to 0.54 Pa and the thixotropic ring area increasing from 0.69 Pa/s to 1.66 Pa/s.And the light transmission of the microgels in AEO and AES can be increased by the TEMPO reaction,but in DDAC the system transmission is lower due to the electrostatic interactions.Meanwhile,the yield stress of the system increased from0.01 Pa to 0.21 Pa as the AEO concentration increased,indicating that there was a large amount of cross-linking between the AEO micelles and the microgels.3.In order to make the synergistic system of bacterial cellulose microgels and HPMC more suitable for use in cationic surfactant systems represented by softener,bacterial cellulose microgels were modified with GTAC(2,3-epoxypropyltrimethylammonium chloride)(G-Microgel).To investigate the effect of different cationic substitution degrees of bacterial cellulose microgels on the rheological properties of the system and on the suspension properties of solid particles.The results showed that the cationic substitution degree of the microgels increased with increasing GTAC concentration,and the highest cationic substitution degree was about 0.0084 when the GTAC concentration was 70wt%,and the yield stress and thixotropic ring of the system gradually increased with increasing microgels concentration.In addition,the yield stress increased from 0.03 Pa to 0.05 Pa in the DDAC system with increasing HPMC concentration,but decreased from 0.10 Pa to 0.06 Pa in the AES system with increasing HPMC concentration,and HPMC shielded the electrostatic interaction between GMicrogel and AES.This paper demonstrates that polyacrylic acid-based suspension stabilizers are only suitable for non-ionic surfactant systems and presents the use of bacterial cellulose microgels as a base to build yielding thixotropic network structures using their specific interactions with neutral water-soluble polymers to achieve stable suspension of solid particles in different surfactant systems.It provides a useful reference for stable suspension of functional solid particles in surfactant products.