Non-adsorbing small molecules as auxiliary dispersants for polycarboxylate superplasticizers was written by Ilg, Manuel;Plank, Johann. And the article was included in Colloids and Surfaces, A: Physicochemical and Engineering Aspects in 2020.Category: ethers-buliding-blocks This article mentions the following:
The dispersing ability of polycarboxylate superplasticizers (PCEs) can be ascribed to the electrostatic and steric stabilization of cement suspensions. For this purpose, PCEs need to adsorb on the cement particle surface to become effective at all. In this study, it is demonstrated that at low water to cement ratios ≤ 0.30, even non-ionic mols. like diethylene glycol or 2-methyl-2,4-pentanediol which do not adsorb on cement, but remain dissolved in the interstitial pore solution, can greatly enhance cement dispersion when combined with PCEs such as conventional methacrylate ester based comb co-polymers. Their effect as co-dispersant is particularly pronounced for PCEs possessing a low side chain d. and long side chain length. Relative to the co-dispersants it was found that especially non-polar small mols. like neopentyl glycol greatly enhance the paste fluidity. These mols. significantly reduce the surface tension of the pore solution and thus increase the wettability of cement. Based on results from spread flow tests, adsorption measurements and pendant drop tensiometry it is concluded that in cementitious systems formulated at low w/c ratios, non-adsorbing mols. with a mol. weight of ≤ 1000 g/mol induce repulsive depletion forces which prevent cement particles from agglomeration. This way, such small mols. act as auxiliary or co-dispersant when combined with PCEs. In the experiment, the researchers used many compounds, for example, 2-(2-Methoxyethoxy)ethanol (cas: 111-77-3Category: ethers-buliding-blocks).
2-(2-Methoxyethoxy)ethanol (cas: 111-77-3) belongs to ethers. Of all the functional groups, ethers are the least reactive ones. Ether bonds are quite stable towards bases, oxidizing agents and reducing agents. But on the other hand, ethers undergo cleavage by reaction with acids. Ethers feature bent C–O–C linkages. In dimethyl ether, the bond angle is 111° and C–O distances are 141 pm. The barrier to rotation about the C–O bonds is low. The bonding of oxygen in ethers, alcohols, and water is similar. In the language of valence bond theory, the hybridization at oxygen is sp3.Category: ethers-buliding-blocks
Referemce:
Ether – Wikipedia,
Ether | (C2H5)2O – PubChem