Understanding Cellulose Ethers and Their Applications in Various Industries
Generally, three principle working mechanisms for water retention can come into place whenever a cement paste is subject to filtration on a substrate. These potential mechanisms have been proposed in earlier works by Desbrières and are as follows [20], [21]: (a) Water retention as a result of increased viscosity: increased dynamic filtrate viscosity can decelerate the filtration rate. (b) Water retention as a result of adsorption: anionic polymers may adsorb onto hydrating cement particles and obstruct filter cake pores either by polymer segments which freely protrude into the pore space or even bridge cement particles. Through this mechanism, filter cake permeability is reduced. (c) Water retention as a result of physical pore plugging: polymers may plug pores in the cementitious matrix through formation of polymer films (e.g. latexes), or through large polymer associates which form a 3D network, or through simple swelling and expansion caused by the uptake of an enormous amount of water into the inner sphere and hydrate shells of polymers. This process leads to the formation of large microgel particles. Through this mechanism, a large portion of the mixing water is physically bound and cannot leak-off into a porous substrate. The enormous water-binding capacity of polysaccharides has been described in an earlier study. By using a sorption balance and a microcalorimeter it was found that at the saturation level, neutral polysaccharides (amylose and amylopectin) can bind up to four water molecules per anhydroglucose unit [22].
MHEC powder finds extensive utilization within the construction sector, particularly in applications such as wall putty, tile adhesives, grouts, and waterproofing compounds. Its exceptional thickening, binding, and water retention properties make it an indispensable choice in this domain.
MHEC powder exhibits a fibrous appearance, presenting as a white to off-white, odorless powder. It possesses a notably high molecular weight and displays hygroscopic properties, readily absorbing water to form viscous solutions or gels. The solubility of MHEC varies contingent upon the degree of substitution (DS) and molecular weight.