Polyvinyl alcohol, which is produced commercially from polyvinyl acetate through hydrolysis usually by a continuous process, is easily degradable by biological organisms and in water is a solubilized crystalline structure polymer.
Polyvinyl alcohol for food use is an odourless and tasteless, translucent, white or cream-colored granular powder. Polyvinyl alcohol is a biodegradable polymer, and its degradability is enhanced through hydrolysis because of the presence of hydroxyl groups on the carbon atoms. Moreover, it is soluble in water, slightly soluble in ethanol, but insoluble in other organic solvents and has a hydrophilic nature.
Typically, a 5% solution of polyvinyl alcohol exhibits a pH in the range of 5.0 to 6.5. Polyvinyl alcohol has a melting point of 180 to 190°C. It has a molecular weight of between 26,300 and 30,000, and a degree of hydrolysis of 86.5 to 89%.
It has been applied in the industrial, commercial, medical, and food sectors and has been used to produce many end products, such as lacquers, resins, surgical threads, and food packaging materials that are often in contact with food. Polyvinyl alcohol is most widely used in the synthesis of poly(vinyl butyral) (PVB) and vinylon fibers. PVB is a low-cost flexible thermoplastic, being used as strong adhesive in multiple applications and might be used in shape memory devices.
Polyvinyl alcohol has various applications in the food industries as a binding and coating agent. It is a film coating agent specially in applications where moisture barrier/ protection properties are required.
As a component of tablet coating formulations intended for products including food supplement tablets, Polyvinyl alcohol protects the active ingredients from moisture, oxygen and other environmental components, while simultaneously masking their taste and odor.
Polyvinyl alcohol (PVOH)
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Structure of polyvinyl alcohol |
