Polyvinyl alcohol surface modification

Surface Modifications of Cellulose and Polyvinyl Alcohol, and Determination of the Surface Density of the Hydroxyl Group... 

Very often used in various applications are the monoliths whose preparation routes involve chemical modifications with ethylenediamine, diethylamine or periodate, as well as grafting of monolithic pore surface via attachment of glucose, polyvinyl alcohol, dextran, ethyl cellulose, or 1,3-di-trimethylolpropane [122,128,164—167]. 

Other hydrophihc polymers have been conceived as alternatives to dextran [6]. For example, polyvinyl alcohol and polyacryl acid derivatives are feasible and graft combinations thereof have been shown to be applicable to SPR detection [14]. Poly-L-lysine has become popular for DNA microarray coatings, due to its highly positive charge. It has also been attached to SAM-derivatized gold surfaces for subsequent modification with thiol reactive groups [15]. 

In an early study by Lin et al., insulin-loaded polylactic acid (PLA) microcapsules were synthesized by an emulsification-solvent evaporation process originally reported by Beck et al. Several parameters in the synthesis process were modified with the intention of optimizing the insulin release profile. Such modifications included variations in types, concentrations, and viscosities of protective colloids used in the emulsification process. Polyvinyl alcohol (PVA), when used as the protective colloid in the fabrication process, was found to produce the PLA microparticles in reproducible quality. Further studies revealed that the concentration PVA directly affects the PLA particle size and the surface characteristics of the microcapsules. With higher concentrations of PVA, microparticles tended to be smaller and to have a smoother surface. When the release profiles of the microcapsules were stud-... 

In the modification with water-soluble polymers such as cellulose derivatives and polyvinyl alcohol, small amounts of the polymers are added as powders or aqueous solutions to cement mortar and concrete during mixing. Such a modification mainly improves their workability because of the surface activity of the water-soluble polymers, and prevents the dryout phenomena (explained in Ch. 4, Sec. 3.1, Water Retention). The prevention of the dry-out is interpreted in terms of an increase in the viscosity of the water phase in the modified cement mortar and concrete and a sealing effect due to the formation of very thin and water-impervious film in them. In general, the water-soluble polymers hardly contribute to an improvement in the strength of the modified systems. 

Modification of cement mortar and concrete by small amounts of water-soluble polymers such as cellulose derivatives and polyvinyl alcohol is used popularly for improving workability. In this case, the water-soluble polymers are mixed with the mortar and concrete as powders or aqueous solutions, and act as plasticizers because of their surface activity. 

Polypropylene, polyethylene, and its copolymers, including polyvinyl alcohol-co-ethylene (EVAL) and polyethylene-co-maleic anhydride, are often reported in the literature as affinity supports for different ligand chemistries (Figure 6.5). Bare polyethylene and polypropylene membranes have good thermal, mechanical, and chemical resistance but are inert and show a too high nonspecific adsorption of biomolecules. Therefore, an additional surface modification step... 

---