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Cellulose nanocrystals (CNC) are formed by the acid hydrolysis of native cellulose fibers, most commonly using sulfuric or hydrochloric acid. Disordered sections of native cellulose are hydrolysed and after careful timing, the remaining crystalline sections can be retrieved from the acid solution by centrifugation and dialysis against water.
Whereas starch undergoes a crystalline to amorphous transition when heated beyond 60–70 °C in water (as in cooking), cellulose requires a temperature of 320 °C and pressure of 25 MPa to become amorphous in water. [19] Several types of cellulose are known. These forms are distinguished according to the location of hydrogen bonds between and ...
The Dumas method of molecular weight determination was historically a procedure used to determine the molecular weight of an unknown volatile substance. [1] [2]The method was designed by the French chemist Jean Baptiste André Dumas, after whom the procedure is now named.
Carboxymethyl cellulose (CMC) or cellulose gum [1] is a cellulose derivative with carboxymethyl groups (-CH 2-COOH) bound to some of the hydroxyl groups of the glucopyranose monomers that make up the cellulose backbone. It is often used in its sodium salt form, sodium carboxymethyl cellulose. It used to be marketed under the name Tylose, a ...
In chemistry, the dispersity is a measure of the heterogeneity of sizes of molecules or particles in a mixture. A collection of objects is called uniform if the objects have the same size, shape, or mass. A sample of objects that have an inconsistent size, shape and mass distribution is called non-uniform.
In chemistry, the mass concentration ρ i (or γ i) is defined as the mass of a constituent m i divided by the volume of the mixture V. [1]= For a pure chemical the mass concentration equals its density (mass divided by volume); thus the mass concentration of a component in a mixture can be called the density of a component in a mixture.
Hydroxyethyl cellulose is a gelling and thickening agent derived from cellulose. It is widely used in cosmetics, cleaning solutions, and other household products. [ 1 ] Hydroxyethyl cellulose and methyl cellulose are frequently used with hydrophobic drugs in capsule formulations, to improve the drugs' dissolution in the gastrointestinal fluids.
Because cellulose is very crystalline, HPC must have an MS about 4 in order to reach a good solubility in water. HPC has a combination of hydrophobic and hydrophilic groups, so it has a lower critical solution temperature (LCST) at 45 °C. At temperatures below the LCST, HPC is readily soluble in water; above the LCST, HPC is not soluble.