Polyvinyl alcohol adsorption

Seeded Polymerisation after Polyvinyl Alcohol Adsorption. 

Chibowski, S., Effect of the ionic composition of the solution on the polyvinyl alcohol adsorption on the surface of AIT),. Mater. Chem. Phys., 20, 65, 1988. 

Chibowski, S. and Szczypa, J., Study on polyvinyl alcohol adsorption at the hematite-aqueous solution interface, Pol. J. Chem., 61. 171, 1987. 

Hydrophilic interaction chromatography on Asahipak NH2P or Excel-pak CHA-P44 with pulsed amperometric detection has been used to fractionate malto-oligosaccharides.266 The Asahipak NH2P is a polyvinyl alcohol support with a polyamine bonded phase, and the Excelpak is a sulfonated polystyrene in the Zn+2 form. Amine adsorption of sialic acid-containing oligosaccharides was performed on a Micropak AX-5 column (Varian) using acetonitrile-water-acetic acid-triethylamine.267... 

A colloidal suspension of conductive vanadium pentoxide [130] can be used to perform intercalation, adsorption or encapsulation of electroactive molecules or biomolecules for electrodes or biosensor realization [131]. Encapsulation of glucose oxidase in nanocomposite films made with polyvinyl alcohol and V205 sol-gel matrix or in ferrocene intercalated V2Os sol-gel [132] were envisaged to prepare glucose biosensors. 

Adsorption-Desorption Behavior of Polyvinyl Alcohol on Polystyrene Latex Particles... 

The adsorption of fully and partially hydrolyzed (88%) polyvinyl alcohol (PVA) on 190-1lOOnm monodisperse polystyrene latex particles was investigated. The effect of molecular weight was investigated for 190 nm-size particles using the serum replacement adsorption and desorption methods. The adsorption density at the adsorption-isotherm plateau followed the relationships for the fully hydrolyzed... 

Polymer adsorption is important in the flocculation and stabilization of colloidal sols and has been reviewed by Vincent et al. (1) and Tadros (2). Polyvinyl alcohol (PVA) has been used in these studies because of its practical application in textiles, adhesives, and coatings. The adsorption of PVA has been studied on silver iodide by Fleer (3) and Koopal (4), and on polystyrene (PS) latex particles by Garvey (5). The adsorption isotherms reported by these workers extend up to 600 ppm PVA. The adsorption at... 

Fig. 4.16 provides an illustration of the adsorption of a neutral polymer, polyvinyl alcohol, on a polar surface, and the resulting effects on the double layer properties. Adsorption of anionic polymers on negative surfaces - especially in the presence of Ca2+ or Mg2+ which may act as coordinating links between the surface and functional groups of the polymer - is not uncommon (Tipping and Cooke, 1982). 

Chiellini E, Corti A, Politi B, Solaro R (2000) Adsorption/desorption of polyvinyl alcohol on solid substrates and relevant biodegradation. J Polym Environ 8 67-79... 

The most popular thin layer is silica gel, and it is estimated that about 90% of TLC separations are performed on standard TLC silica plates a common size is 20 cm square and 250 g,m thick. Binders, in amounts up to 15%, are usually used to produce a stable layer and good adherence to the backing plate, but plates can be made without binders. Calcium sulfate (gypsum, designated with a G in the name, e.g., silica gel G) and polyvinyl alcohol (PVA) are most common. The PVA plates are very stable and will withstand rather rough handling. While it is not difficult to make one s own plates, most laboratories prefer commercially prepared plates, especially those made with PVA. It must not be forgotten, however, that both binders will modify the adsorption properties of the silica and can produce somewhat different separations. 

Quite similar results have been reported by van Vliet [226]. He found that the equilibrium thickness of foam films from aqueous solutions of polyvinyl alcohol at low pressure is much larger than twice the adsorption layer thickness measured by ellipsometry. The core thickness is again several times the radius of gyration of the polymer molecules in... 

The stabilising action of the adsorption layers from high molecular substances (protective colloids) is related to the decrease in the forces of molecular attraction. Hence, films from aqueous solution of polyvinyl alcohol obtained between drops of cyclohexane have thickness of 80 nm and respectively, a very low attraction force, in contrast to black films [513]. Along with that the adsorption layers from such compounds possess visco-elasticity properties with modulus of elasticity 104 N m"2, impeding the film thinning and drop coalescence [503]. 

Adsorption of Polyvinyl Alcohols by Polyvinyl Acetate Latex. 

To assess the effect of an adsorbed layer of polyvinyl alcohol on the rate of polymerisation, the rates of seeded polymerisation were measured after adsorption of various grades of polyvinyl ailcohol on the seed latex. The seed latex was prepared in the same way as the latex used in the adsorption experiments. After adsorption of polyvinyl alcohol from a 0.10 % w/v solution, the concentration of the seed latex wets 0.9A5 % w/v in a 2.0 % v/v vinyl acetate solution containing 7.4 x 10" mol dm" potassium persulphate. The rates of polymerisation (the means of two to four experiments) observed at 60 C are tabulated below. 

Polyviol V/25/140 which is the most strongly adsorbed grade (Fig. 4) has the greatest effect in reducing the rate of polymerisation but Qohsenol QM-14 L and GH-23 which are only weakly adsorbed (Fig. 4) are more effective than Qohsenol NH-17 and GH-17 which are more strongly adsorbed. Once again it seems that some other factor is having more effect on the rate of polymerisation than the extent of adsorption of the polyvinyl alcohol. 

To stabilize proteins against these degradative steps, excipients have proven to be quite effective. For instance, surfactants such as polysorbates, polyvinyl alcohol and (hpamitoyl phosphatidyl choline have been used to prevent the adsorption of proteins at the air-hquid interface during spray drying [8, 9],... 

Chibowski, S., Effect of the molecular weight of polyvinyl alcohol on some adsorption parameters in titania-polymer solution system, Croat. Chem. Acta, 63, 91, 1990. 

Chibowski, S., Dependence of the adsorption behavior of polyvinyl alcohol at the polystyrene latex-solution interface on the molecular weight, J. Colloid Interf. Sci., 134. 174. 1990. 

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