Epoxidized soybean oil (ESO) was cured with a terpene-based acid anhydride (TPAn) at 150 degrees C, and the thermal and mechanical properties of the cured product were compared with ESO cured with hexahydrophthalic anhydride (HPAn), maleinated linseed oil (LOAn), or thermally latent cationic polymerization catalyst (CPI). The ESO-TPAn showed a higher glass transition temperature (67.2 degrees C) measured by dynamic mechanical analysis than ESO-HPAn (59.0 degrees C), ESO-LOAn (-41.0 degrees C), and ESO-CPI (10.0 degrees C). The storage modulus at 20 degrees C of ESO-TPAn was higher than those of ESO-LOAn and ESO-CPI. Also, ESO-TPAn showed higher tensile strength and modulus than the other cured ESOs. Regarding the biodegradability measured by biochemical oxygen demand in an activated sludge, ESO-TPAn possessed some biodegradability, which was lower than that of ESO-LOAn. Next, biocomposites composed of ESO-TPAn and regenerated cellulose (lyocell) fabric were prepared by compression molding method. The tensile strength of ESO-TPAn/lyocell composites increased with increasing fiber content. The tensile strength and modulus of ESO-TPAn/lyocell composite with fiber content 75 wt% were 65 MPa and 2.3 GPa, which were three times higher than those of ESO-TPAn. (c) 2008 Wiley Periodicals, Inc.