Physical and chemical properties of polyvinylpyrrolidone
Physical properties:
①Solubility and mutual solubility
PVP is soluble in various alcohols, amines, amides, halogenated hydrocarbons, nitroalkanes, and low molecular fatty acids except for a few solvents such as ether, acetone, turpentine, aliphatic alicyclic hydrocarbons, etc. Compatible with a small number of aromatic hydrocarbons and esters. A distinctive feature of PVP is that it is extremely soluble in water.
②Film-forming and adhesive
PVP solution can be cast into a transparent and bright film with certain stiffness. PVP film also has excellent adhesive properties and can be used as an adhesive for paper, glass and metal. However, PVP film has strong hygroscopicity, and its water absorption order is: carboxymethyl cellulose>PVP>polyvinyl alcohol. But the hygroscopicity of PVP film can be improved by copolymerization or miscibility modification with other resins.
2.Chemical properties:
①Chemical stability
PVP has good thermal stability. Heating in air. No obvious change below 130140 degree . The temperature exceeds 150 degree . PVP will undergo cross-linking reaction. When protected by an inert gas, PVP can withstand higher temperatures without significant degradation for a certain period of time. PVP is more sensitive to strong bases, and when the two aqueous solutions are mixed and heated, gelation will occur quickly, resulting in a water-insoluble gel.
②The surface activity of surface-active
PVP is shown in: PVP has a solubilizing effect, is used as a solubilizer for dyes in dyeing in the printing and dyeing industry, and is used to increase the water solubility of some substances that are basically insoluble in water but have pharmacological activity; dispersing effect, It can make the colored substances, suspensions, and emulsions in the solution disperse uniformly and maintain stability; the adsorption effect is easy to adsorb on many interfaces and reduce the interface surface force to a certain extent. It also has the functions of wetting, foam stabilization and decontamination, and is widely used in daily chemical products.