Foaming resol resin modified with polyhydroxylated cardanol and its application to phenolic foams

Cardanol, obtained from cashew processing industry, has attracted more and more attention from researchers for developing phenolic foam (PF) toughness. In the present work, polyhydroxylated cardanol (PHC) was obtained from C=C in unsaturated side chain of cardanol under the condition of H2O2 and HCOOH, then it and phenol reacted with formaldehyde to successfully formulate foaming resol resin. The replacement percentage of phenol by PHC was up to 20% (wt/wt), 10% higher than that of literatures reported. Phenolic foam (PF) was fabricated with the above foaming resol resin and certain foaming agents. Its compressive strength and flexural strength were surprisingly increased by 57% and 56%, respectively, compared to conventional PF. (C) 2015 Elsevier B.V. All rights reserved.