Ionic polycondensation effects on the radical autocondensation of polyflavonoid tannins: An ESR study

✍ Scribed by R. Garcia; A. Pizzi; A. Merlin

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 272 KB
• Volume: 65
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/(sici)1097-4628(19970926)65:13<2623::aid-app4>3.0.co;2-d

✦ Synopsis

An electron spin resonance (ESR) study of the presence or lack of interference by ionic hardening mechanisms and ionic coreactants on the polyflavonoid tannin radical autocondensation reaction indicated that in certain cases hardening by ionic coreactants can be coupled with the simultaneous hardening of the tannin by radical autocondensation. Some coreactants tend to depress the tannin radical autocondensation while still leaving a small contribution of this reaction to the formation of the final crosslinked network. Other coreactants instead appear to enhance formation of the final network by synergy between ionic and radical mechanisms, while still others do not show any interference between the two types of reaction. Mechanisms describing the interaction between the two reactions are proposed and discussed.