Storage

The material is very stable with no risk of molding and deteriorating. Under dry conditions, it remains stable indefinitely when protected from moisture.

Dissolving Method

Pour a certain amount of water into the dissolving tank. The water temperature should be below 30°C, then start the blender and pour PVA slowly. The filling speed with PVA should be kept to 10 kilograms per minute; this is advisable.

Confirm that the PVA has fully dispersed (about 10-20 minutes), then heat the solution, and it can be completely dissolved when the temperature reaches 90°C, about 1 hour.

Method of Analysis

Viscosity is measured in a 4% aqueous solution at 20°C using a Brookfield-type viscometer.

pH is measured in a 4% aqueous solution at 20°C.

Ash is expressed as Na₂O.

Polyethylene glycols (PEGs) are condensation polymers of ethylene oxide and water with the general formula H(OCH2CH2)nOH. They are the most commercially important type of polyether. The low molecular weight compounds up to 700 are colorless, odorless viscous liquids with a freezing point from -10˚C (diethylene gycol), while polymerized compounds with higher molecular weight than 1,000 are wax like solids with melting point up to 67˚C. While PEGs with different molecular weights find use in different applications and have different physical properties (e.g. viscosity) due to chain length effects, their chemical properties are nearly identical.

 

The numbers that are often included in the names of PEGs indicate their average molecular weights, e.g. a PEG with n=9 would have an average molecular weight of approximately 400 and would be labeled PEG 400. Most PEGs include molecules with a distribution of molecular weights, i.e. they are polydisperse.