A commercial norbornyl-functionalized linseed oil, blended with a bicyclic norbornene-based crosslinking agent (at loadings ranging from 0 to 50 wt %) undergoes ring-opening metathesis polymerization with the 1st generation Grubbs' catalyst to form a biorenewable polymer network. Comonomers are characterized, the thermal and mechanical properties of the cured systems are investigated by dynamic mechanical analysis, and thermal decomposition is evaluated by thermogravimetric analysis. The resin is shown to consist of a modified linseed oil and small oligomers of cyclopentadiene. Broad tan 6 peaks suggest inhomogeneous phase morphologies, which result in complex crosslinking behaviors. The thermal stability of the polymers increases with increasing crosslinker content. (c) 2008 Wiley Periodicals, Inc.