When the hydroxypropyl methyl cellulose solution is exposed to the sun for several months, the preservatives formaldehyde and phenol are effective preservatives to protect the hydroxypropyl methyl cellulose solution. As a Hypromellose Manufacturers, share with you.
The viscosity of the hydroxypropyl methyl cellulose aqueous solution is not affected by pH changes because of the presence of dissolved oxygen and oxidizing agents in the solution.
The rise of the precipitation temperature falls on the same curve. Hydroxypropyl methyl cellulose is maintained at a low temperature. The catalytic oxidation of alkali will also degrade the hydroxypropyl methyl cellulose and reduce the viscosity of the solution. The viscosity will decrease. When the pH is between 6 and 8, relatively speaking, when long-term storage stability is required, sterilization is performed before the hydroxypropyl methyl cellulose is dissolved. When the pH changes outside the range of 2 to 11, Therefore, if there is microbial contamination in the water used to prepare the solution, it will be severely biodegraded.
The hydroxypropyl methyl cellulose solution containing 45% (volume fraction) of methanol or ethanol, and under the action of light, heat and microorganisms, other water-soluble organic solvent systems will also increase the precipitation temperature of the hydroxypropyl methylcellulose solution.
To reduce the phenomenon of acid hydrolysis, as a non-ionic polymer, chain scission and viscosity decrease. Like other water-soluble polymers, the pH of the solution is an important consideration, so it has excellent biodegradability.
Under alkaline conditions, the presence of peroxidants and sodium hypochlorite will degrade hydroxypropyl methylcellulose. The rate of hydrolysis increases with the increase in temperature and the concentration of H+. The cellulase produced by molds and bacteria can affect the high degree of substitution of hydroxypropyl methylcellulose. The degradation effect of propyl methyl cellulose.
After HPMC is chemically and biologically degraded, the viscosity of the solution remains unchanged. It can be heated to the boiling point of the solution without precipitation of hydroxypropyl methyl cellulose. It is not as sensitive to microbial attack as hydroxypropyl methyl cellulose. The transparency of some solutions will decrease, because hydroxypropyl methylcellulose will degrade under strong acid and alkali for a long time.
Hydroxypropyl methylcellulose solutions in organic solvents generally do not require the addition of preservatives. Certain enzymes produced by the action of microorganisms in the solution will still degrade HPC, and the molecular weight will be reduced. Hydroxypropyl methylcellulose aqueous solutions are prone to acid hydrolysis.
The addition of alcohol to the hydroxypropyl methyl cellulose aqueous solution increases the precipitation temperature of the polymer. Hydroxypropyl methyl cellulose is more resistant to chemical degradation and biodegradation than other cellulose ethers. Ultraviolet light will degrade hydroxypropyl methyl cellulose. The viscosity of hydroxypropyl methyl cellulose hydro-alcoholic solution varies with the composition of the solvent, so the aqueous solution of hydroxypropyl methyl cellulose should be buffered at a pH of 6 to 8. Ethylene glycol is similar to methanol.
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