Study On Surface Properties Of Aliphatic Alcohol Polyoxyethylene Ether And Its Application

The critical micelle concentration(cmc), the equilibrium surface tension (γcmc),the standard free energy of micellization (ΔGm),and area per molecular at cmc (cmc) at the water-air interface were determined as a function of the total hydrocarbon number(m)n=7in the lipophilic part and oxyethylene group number(n)m=12in the hysrophilic part of the Fatty Alcohol-polyoxyethylene(FAPE) surfactants.We also explored the effect of ionic strength on cmc and surface tension of the surfactants in triple hard water. HLB values of FAPE with different EO chains and carbon chains were determined by water counting methods..It also studied the influence of AEO with different EO number as dispersants on the rheological properties (viscosity, storage modulus G’,γflow and thixotropy) and the physical stability (the suspension rate before and after the hot storage, residual pourability ratio) of Mancozeb25%suspension concentrate (SC).By comparing γflow with the result of physical stabilitity test,, we find the values of G’and γflow reflect the structural variation of the SC,and then G’and γflow can be used as suitable SC stability indicators.With the rheological index of G’and γflow, we got stable40%thiram-SYP-2048suspoemulsion (SE) by technology and surfactant screening.The increase of the oxyethylene group number from4to20leads to the increase of cmc, γcmc,ΔGm、Acmc.The increase of (m)n=7from10to16leads the cmc, γcmc,ΔGmand Acme fluctuate within a certain range rather than decreasing.In triple hard water, as EO chain is easily affected by ionic strength,cmc is much more susceptible by the ions than γcmc and the the change of EO chain has greater affects on the variation of γcmc than carbon chains.By comparing the measured HLB values with the corresponding calculated HLB values from the references, we draw a conclusion that1,4-dioxane/benzene solvent is more excellent solvent system for AEO surfactants HLB analysis.And The increase of the oxyethylene group number from4to20leads to the increase of HLB,and the increase of (m)n=7, from10to16leads the decrease of HLB.The adding of AEO can reduce the viscosity of Mancozeb25%SC, and the SC with AEO-9has the lowest viscosity. With the increase of the EO chains in AEO, the thixotropy recovery of SC which has higher residual pourability ratio decreases gradually. Through strain sweep, we find the values of G’and γflow reflect the structural variation of the SC,and then G’and γflow can be used as suitable SC stability indicators.In the process of preparating40%thiram-SYP-2048suspoemulsion (SE), we found that the method of mixing water emulsion and water dissolving is better, and then we can get stable SE,which is not easy to crystallization, Phosphate ester and naphthalene sulfonic acid salts are good dispersants in the SE.