【Detail】
PVP application in Polymerization
PVP has important application in polymerization by its viscosity and colloid protection function. Especially in emulsion polymerization and suspension polymerization, adding a small amount of PVP could play the function of stable dispersion, thickening and control of particle size, For example in the suspension polymerization of methyl acrylate and polyurethane and in the emulsion polymerization of Acrylate and vinyl acetatesuspension , adding proper amount of PVP-K60 or PVP and styrene copolymer could make the reaction system uniform dispersion stability . Moreover through adjust the PVP molecular weight and dosage to adjust viscosity and the distribution of polymer particle size and size distribution, improving the performance of resin. By adding 3% PVPK60 on the suspension polymerization of polyurethane to get the epigranular Polymer powder with Particle size between 800 ~ 100 microns, the residual monomer is less than 0.5%. It could be used as Coatings, adhesives and laminated composite materials, when as film, the thick up to 100 microns, as paint, coating can be as small as 10 micron.
In some emulsion polymerization system , adding PVP K15,PVP K30 which have the Low molecular weight as emulgator to make the reaction more fully and improve the polymerization rate and the mechanical properties of polymers .For example ,in the methyl methacrylate polymerization ,we could add PVP K15 as emulgator , it can be finished in half an hour At 50℃, the elastic temperature of the resulting polymer range from 120℃ to 280 ℃. if not add PVP , the elastic temperature only range from 120℃ to 150 ℃.so use PVP as dispersion stabilizer could make polymer in better thermal stability.
Application of PVP in analytical chemistry and catalyst
PVP aqueous solution in different amount of (NH4)2SO4 could be divided into liquid - liquid or liquid-solid two phase, this system are used for metal ions by organic solvent ’s extraction separation to get the new extraction system. This system has better extraction effect used for some metal ions. such as in PVP-（NH4）2SO4-H2O system which contain PVP 20% , by using Arsenazo (III) for extractant ,effect with solution contain Zr (IV) and La (III) to form the complex compound. Under a certain condition ,the chelate of Zr (IV) and azo arsine in PVP has a high extraction rate ,but La (III) in PVP is very low .Thus by using PVP could separate Zr (IV) and La (III), otherwise,PVP has good Complexation property with some metals ,such as PVP with Cd can generate PVP - Cd by Complexation, by using this property can successful to detected trace cadmium. According to the related research reports, for methanol carbonylation reaction, PVP-Rh/C activity and selectivity are much larger than Rh/C ,the reason is that the colloidal metal catalyst particles which LW and PVP formed has the characters of narrow particle diameter distribution, high dispersion degree and the increased specific surface area .So it improve the catalytic activity and at the same time improve the selectivity of the reaction .
