In the present study, the curing behavior of polycardanol prepared by enzymatic oxidative polymerization of thermally treated cashew nut shell liquid, which can be available from naturally renewable resources, was explored in the presence of methyl ethyl ketone peroxide (MEKP) and cobalt naphthenate (Co-Naph). The curing behavior was monitored varying Co-Naph concentration and curing temperature by means of Fourier transform infrared (FT-IR) spectroscopy. The result revealed that the characteristic absorption bands were significantly affected by the given curing condition, resulting mainly from the unsaturated moiety in the polycardanol molecule. The extent of curing of polycardanol strongly depended on curing temperature, showing a typically sigmoidal curve reaching almost 1.0 upon processing at 200 degrees C for 120 min. The thermal curing conditions for preparing polycardanol with an optimal state of cure were provided in the work. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 122: 2774-2778, 2011