Polyvinyl alcohol crosslinking

L Chen, SH Imam, SH Gordon, RV Greene. Starch polyvinyl alcohol crosslinked film—Performance and biodegradation. J Environ Polym Degradation 5 111-117, 1997. 

Chen L., Imam SH, Gordon SH, Greene RV. 1997, Starch-polyvinyl alcohol crosslinked film- performance and biodegradation, J.Environ. Polym.Degrad. 5 111-117... 

Chen, L., Imam, S.H., Gordon, S.H., and Green, R.V., 1997, Starch-Polyvinyl Alcohol Crosslinked Film - Performance and Biodegradation. J. Environ. Polym. Degr. 5 111-117. 

Polyvinyl alcohols may be applied as such or in crosslinked form [90]. Crosslinkers can be aldehydes (e.g., formaldehyde, acetaldehyde, glyoxal, glutaraldehyde), to form acetals, maleic acid or oxalic acid to form cross-linked ester bridges, or others (e.g., dimethylurea, polyacrolein, diisocyanate, divinyl sulfonate) [89,91]. 

Microgels can not only be synthesized by polymerization but also by polycondensation or polyaddition [350]. In an early work on crosslinking of single linear macromolecules, it could be shown that if a crosslinking agent, such as terephthal dialdehyde, was added to a very dilute solution of a linear polymer such as polyvinyl alcohol, almost exclusively a intramolecular crosslinking of the individual macromolecules took place [351]. 

Polyvinyl alcohol (PVA), which is a water soluble polyhidroxy polymer, is one of the widely used synthetic polymers for a variety of medical applications [197] because of easy preparation, excellent chemical resistance, and physical properties. [198] But it has poor stability in water because of its highly hydrophilic character. Therefore, to overcome this problem PVA should be insolubilized by copolymerization [43], grafting [199], crosslinking [200], and blending [201], These processes may lead a decrease in the hydrophilic character of PVA. Because of this reason these processes should be carried out in the presence of hydrophilic polymers. Polyfyinyl pyrrolidone), PVP, is one of the hydrophilic, biocompatible polymer and it is used in many biomedical applications [202] and separation processes to increase the hydrophilic character of the blended polymeric materials [203,204], An important factor in the development of new materials based on polymeric blends is the miscibility between the polymers in the mixture, because the degree of miscibility is directly related to the final properties of polymeric blends [205],... 

The first modern day negative photoresists were developed by the Eastman Kodak Company which utilized cyclized rubbers and cinnamic acid derivatives as photosensitive crosslinking agents (42). The first commercially important photoresist based on this chemistry was known as KPR, which was of a cinnamate ester of polyvinyl alcohol. It was introduced by Kodak in 1954. 

Other common binders include nitrocellulose (acetone as the solvent), polyvinyl alcohol (used with water), and Laminae (an unsaturated polyester crosslinked with styrene — the material is a liquid until cured by catalyst, heat, or both, and no solvent is required). Epoxy binders can also be used in hquid form during the mixing process and then allowed to cure to leave a final, rigid product. 

Research Focus Crosslinking polyvinyl alcohol as a method of enhancing its... 

Additional crosslinked polyvinyl alcohol copolymers, (I), were prepared by Schulte et al. (1) and used as components in adhesives, emulsifiers, and detergents. 

Unfortunately, the reaction of the diacid-modified AIBN with polyvinyl alcohol led to crosslinking due to the reaction of the modified AIBN with two independent polymer chains. The insolubility of such crosslinked products make such a process technically impractical. 

A list of typical commercial pervaporation membranes [23] is given in Table 3.1. Commercial hydrophilic membranes are very often made of polyvinyl alcohol (PVA), with differences in the degree of crosslinking. Commercial hydrophobic membranes often have a top layer in polydimethyl siloxane (PDMS). However, a wide variety of membrane materials for pervaporation can be found in the literature, including polymethylglutamate, polyacrylonitrile, polytetrafluoroethylene, polyvinylpyrrolidone, styrene-butadiene rubber, polyacrylic acid, and many others [24]. A comprehensive overview of membrane materials for pervaporation is given by Semenova et al. [25],... 

Fig. 9. Exclusion molecular weight of polyvinyl acetats crosslinked with 20% 1,4 butanediol divinyl ether iner compound i-amyl alcohol / i-octane, abscissa given in volume fraction of nonsolvent...

Electrophoresis protein separation membranes have been prepared by step-growth condensation of water-soluble polyvinyl alcohol with selected water-soluble difunctional crosslinking agents. These membranes have broad pore size ranges, restricted pore size distribution, greater resistance to hydrolysis in an alkaline medium, and improved gel clarity when higher amounts of crosslinkers are used. 

Preparation of Polyvinyl Alcohol Membrane Crosslinked with Glutaraldehyde... 

TABLE 1. Membranes prepared by reacting selected crosslinking agents with 10 ml of 5% solution of polyvinyl alcohol having a M of ronghly 20,000 daltons and 97.5% to 99.5 % hydrolyzed. 

TABLE 2. Experimental electrophoresis protein separation conditions using membranes prepared by reacting polyvinyl alcohol having a M of roughly 20,000 daltons 97.5% to 99.5% hydrolyzed and selected crosslinking agents. 

Thanoo BC, Sunny MC, Jayakrishnan A. Controlled release of oral drugs from crosslinked polyvinyl alcohol microspheres. J Pharm Pharmacol 1993 45 16-20. 

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