Three Methods for In Situ Cross-Linking of Polyvinyl Alcohol Films for Application as Ion-Conducting Membranes in Potassium Hydroxide Electrolyte.
Abstract
Three methods for in situ cross-linking of water soluble polyvinyl alcohol films are presented. These cross-linked films show promise for use as battery separators in aqueous potassium hydroxide (KOH) electrolyte. Electrical resistivities in KOH of cross-linked membranes representing the three procedures are given with a brief discussion of the chemical mechanism involved in their preparation. Physical properties, such as mechanical strength and swelling in alkaline electrolyte, are discussed. The three cross-linking techniques entail: (1) Treating a polyvinyl alcohol membrane containing a specified amount of a dialdehyde such as glutaraldehyde with an acid solution which catalyzes acetalization cross-linking. (2) Treating a polyvinyl alcohol film with periodic acid which cleaves the few 1, 2 diol units present in polyvinyl alcohol with the formation of aldehyde groups which then causes cross-linking via acetalation of the 1, 3 diol units. (3) Reacting a polyvinyl alcohol film with hydrogen atoms and hydroxyl radicals from irradiated water whereby cross-linking is accomplished by polymer radicals formed as a consequence of hydrogen abstraction. Hydrogen abstraction cross-linking of films containing both polyvinyl alcohol and polyacrylic acid in polymer solution improves strength in 45 percent KOH. Films made from solely polyacrylic acid were unsatisfactory. jg p3
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1979
- Accession Number
- ADA304743
Entities
People
- Li-chen Hsu
- Warren H. Philipp
Organizations
- Glenn Research Center