Glycerol Monostearate
About This Product
Glycerol monostearate is the non-ionic glycerol ester of stearic acid, a milky white to pale yellow waxy or powdery solid, odourless and tasteless, with a freezing point of 60-70C. Made by esterifying glycerol with fatty acids, it is supplied in a 40% monoglyceride grade and a distilled 90% grade, and is vegetable-based, from palm-derived fatty acids. In a polymer compound glycerol monostearate is doing something quite different from its role in food. It is an internal antistatic: the polar hydroxyl groups are driven out of a non-polar matrix, migrating to the surface over hours or days, where they attract a microscopic moisture layer that bleeds off static charge. That is what stops moulded parts attracting dust and film sticking to itself on a reel. The same migration underlies its use as an antifog additive in agricultural and packaging film, where the bloomed layer lowers interfacial tension so condensation spreads as a sheet instead of forming discrete droplets that scatter light. It also functions as an internal lubricant, reducing melt viscosity without the surface effects of an external lubricant. Because the effect depends on migration to the surface, the additive needs time to bloom after processing, and both loading and the choice between the 40% and 90% grades are set by trial against the polymer and the required onset time. It is used as an internal antistatic agent, an antifog film additive and a processing lubricant, and in masterbatch for polyolefin and styrenic compounds. Bio Green Chem supplies glycerol monostearate in 25 kg bags to specification on monoglyceride content, acid value, iodine value, free glycerin and freezing point.
