Preparation of a light color cardanol-based curing agent and epoxy resin composite: Cure-induced phase separation and its effect on properties

► We prepared a light color epoxy curing agent and a phenalkamine derived from cardanols. ► Cure-induced phase separation was found in the cure of the light color curing agent. ► The morphology of the cured light color one consisted of cavities dispersed within a continuous epoxy matrix. ► The phase separation markedly improved the toughness of the cured resin. ► The phase separation also induced more weight loss in the thermogravimetric analyses.