The degree of substitution of CMC is one of the keys to determine the quality, among which the viscosity is mainly related
to the molecular weight, however, it is not too much related to the degree of substitution, but the greater the degree of
substitution, the molecular weight will also increase, What is the degree of substitution of CMC related to?
If the dissolution rate is analyzed, generally speaking, the product with high degree of substitution corresponds to high
viscosity, and the dissolution time is longer than the product with low degree of substitution with low viscosity. In terms
of water solubility, the product with high degree of substitution has good water solubility, while the product with low
degree of substitution has poor water solubility.From structured each glucose units, with a total of three hydroxyl groups
on the C2, C3 and C6 hydroxyl, glucose unit of hydroxyl hydrogen is to replace how many with substitution degree of
carboxymethyl , if the three hydroxyl groups on the each unit of hydrogen are replaced by carboxymethyl, defined as
the substitution degree is 3, the size of the CMC substitution degree directly affect the substitution degree of solubility
and emulsification, thickening, stability, acid resistance and salt resistance performance.
It is generally believed that the emulsification property is better when the degree of substitution is around 0.6-0.7, and
with the increase of the degree of substitution, other properties are changed correspondingly. When the degree of
substitution is greater than 0.8, its acid and salt resistance is significantly enhanced.In addition, the above mentioned
each unit, a total of three hydroxyl groups on the C2 and C3 para hydroxy and C6 primary hydroxyl, the activity of the
primary hydroxyl is greater than the para hydroxy in theory, but according to the C isotopic effect of C2 - OH base on
more acidic, especially under the environment of strong base its activity than C6 C3, stronger, so the substitution reaction
occurred more, C6, C3 is weak.