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Related to this application, propylene glycol reacts with propylene oxide to give oligomers and polymers that are used to produce polyurethanes. [7] Propylene glycol is used in water-based acrylic architectural paints to extend dry time which it accomplishes by preventing the surface from drying due to its slower evaporation rate compared to water.
Examples include ethane-1,2-diol or ethylene glycol HO−(CH 2) 2 −OH, a common ingredient of antifreeze products. Another example is propane-1,2-diol, or alpha propylene glycol, HO−CH 2 −CH(OH)−CH 3, used in the food and medicine industry, as well as a relatively non-poisonous antifreeze product.
Polypropylene glycol is produced by ring-opening polymerization of propylene oxide. The initiator is an alcohol and the catalyst a base, usually potassium hydroxide. When the initiator is ethylene glycol or water the polymer is linear. With a multifunctional initiator like glycerine, pentaerythritol or sorbitol the polymer branches out ...
Propylene glycol. Propylene glycol is considerably less toxic than ethylene glycol and may be labeled as "non-toxic antifreeze". It is used as antifreeze where ethylene glycol would be inappropriate, such as in food-processing systems or in water pipes in homes where incidental ingestion may be possible.
Between 60 and 70% of all propylene oxide is converted to polyether polyols by the process called alkoxylation. [15] These polyols are building blocks in the production of polyurethane plastics. [16] About 20% of propylene oxide is hydrolyzed into propylene glycol, via a process which is accelerated by acid or base catalysis.
Glycol ethers are designated "E-series" or "P-series" for those made from ethylene oxide or propylene oxide, respectively.Typically, E-series glycol ethers are found in pharmaceuticals, sunscreens, cosmetics, inks, dyes and water-based paints, while P-series glycol ethers are used in degreasers, cleaners, aerosol paints and adhesives.
There is a difference in the mixing ratio, depending on whether it is ethylene glycol or propylene glycol. For ethylene glycol, the mixing ratios are typically 30/70 and 35/65, whereas the propylene glycol mixing ratios are typically 35/65 and 40/60. It is important that the mixture be frost-proof at the lowest operating temperature. [24]
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