How to judge the quality of hydroxypropyl methylcellulose (HPMC) simply and intuitively?

(1) Whiteness: Although whiteness cannot determine whether HPMC is easy to use, and if a brightener is added in the production process, it will affect its quality. However, most of the good products have good whiteness.
(2) Fineness: The fineness of HPMC is generally 80 mesh and 100 mesh, and 120 mesh is less. Most of the HPMC produced in Hebei is 80 mesh. The finer the fineness, the better.
(3) Transmittance: Put hydroxypropyl methylcellulose (HPMC) in water to form a transparent colloid, and check its transmittance. The higher the transmittance, the better, indicating that there are less insoluble substances in it . The permeability of vertical reactors is generally good, and that of horizontal reactors is worse, but it cannot be said that the quality of vertical reactors is better than that of horizontal reactors, and there are many factors that determine product quality.
(4) Specific gravity: the larger the specific gravity, the heavier the better. The specific gravity is large, generally because the hydroxypropyl content in it is high, and the hydroxypropyl content is high, the water retention is better.