FILM FORMING PROPERTIES

2019-04-16

COMMERCIAL TYPES OF PVP

PVP polymers are available inseveral viscosity grades, ranging from low to high molecular weight. Thisrange, coupled with solubility in aqueous and organic solvent systems combinedwith its nontoxic character, gives PVP great flexibility. Its industrialapplication include, for example, in adhesives to improve strength andtoughness; in paper manufacture to increase strength and as a coating resin; andin synthetic fibers to improve dye receptivity. It is also widely employed ininks, imaging, lithography, detergents and soaps, the textile, ceramic,electrical, metallurgical industries and as a polymerization additive.


PVP polymer is supplied In five viscositygrades as a powder and/or aqueous solution. The full line of PVP polymers isalso available for personal care applications such as film forming, emulsionstabilization, colorant dispersion, etc. STD also offers pharmaceutical gradesof PVP; our Sunvidone® polymer products are used in the pharmaceuticalindustry.


PHYSICAL AND CHEMICAL PROPERTIES


MOLECULAR WEIGHT DETERMINATION

There have been many studies that have beendevoted to the determination of the molecular weight of PVP. The low molecularweight polymers have narrower distribution curves of molecular entities thanthe high molecular weight compounds. Some of the techniques for measuring themolecular weight of various PVP products are based on measuring sedimentation,light scattering, osmometry, NMR spectroscopy, ebullimometry, and sizeexclusion chromatography for determining absolutemolecular weight distribution.By the use of these methods, any one of three molecular weight parameters canbe measured, namely the number average (Mn),


FILM FORMING PROPERTIES

Dried unmodified films of PVP are clear,transparent, glossy, and hard. Appearance does not vary when films are castfrom different solvent systems, such as water, ethanol, chloroform, or ethylenedichloride.

Compatible plasticizers may be added withoutaffecting clarity or luster of the film. Moisture taken up from the air by PVPcan also act as a plasticizer.

Among the several commercial modifiers thatmay be used in concentrations of 10-50% (base on PVP) to control tack and / orbrittleness or to decrease hygroscopicity.






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