Hydroxypropyl methylcellulose (HPMC) is an odorless, tasteless, non-toxic white powder. After fully dissolving in water, hydroxypropyl methylcellulose will form a transparent viscous colloid. Hydroxypropyl methylcellulose is widely used in many industries, and hpmc is gradually becoming known, and the scope of use is constantly expanding, but how can we distinguish the quality of 100,000-viscosity hydroxypropyl methylcellulose? From what aspects to identify 150,000 viscosity hydroxypropyl methylcellulose, let's analyze the quality of 200,000 viscosity hydroxypropyl methylcellulose from four aspects:
1. Look at the particle size distribution
The good hydroxypropyl methylcellulose has uniform particle size, small particle size, granular shape and good fluidity; the bad one is just the opposite. The fineness of hydroxypropyl methylcellulose is generally 80 mesh and 100 mesh, and 120 mesh is less. Most of the hydroxypropyl methylcellulose produced in Hebei is 80 mesh. The finer the fineness, generally speaking, the better.
2. Looking at the appearance
The appearance of hydroxypropyl methylcellulose is white and uniform, and there are no many black spots under the microscope; the poor color is grayish, with more black spots. Looking at the shape and fluidity of the particles, the particles using degreased cotton as the starting material are long and have poor fluidity, while the particles using lignocellulose as the starting material are close to cubes and have good fluidity
3. Light transmittance
Put hydroxypropyl methylcellulose HPMC into water to form a transparent colloid, and check its light transmittance. The higher the light transmittance, the better, indicating that there are less insolubles in it. The permeability of vertical reactors is generally good, and that of horizontal reactors is worse, but it does not mean that the quality of vertical reactors is better than that of horizontal reactors, and product quality is determined by many factors.
4. Specific gravity
The larger the specific gravity, the heavier the better. The specificity is large, generally because the content of hydroxypropyl group in it is high, and the content of hydroxypropyl group is high, the water retention is better.