Modification of Rubber by Cardanol-Formaldehyde Resins and Epoxidized Cardanol

Cardanol-formaldehyde resin (CF) and cardanol glycidylether (CGE) have been synthesized for reinforcing natural rubber (NR), a blend of NR and styrene-butadiene rubber (SBR), and nitrile-butadiene rubber (NBR). The novolac CF resin reinforced the NR, SBR, and NBR. The resolic CF is not only a reinforcing agent but also a hardener (crosslinking agent) for NBR by means of the methylol groups of CF with the CN- group of NBR. The CGE resin was synthesized by the epoxidation of cardanol by epichlorohydrin; it could be used as a reinforcing agent for NR and for crosslinking maleinized NR. The results of estimates of the physical properties of the vulcanisate, their DSC diagrams, and SEM showed the enhanced properties of the final products.