AbstractA novel furan‐modified thermoreversible crosslinked thermoplastic starch was synthesized. The crosslinking mechanism was based on a thermoreversible furan/maleimide adduct formed by the Diels − Alder reaction. Thermoplastic starch (TPS) was first modified by forming a urethane linkage between the product of the reaction of furfuryl alcohol with 4,4‐methylene diphenyldiisocyanate and a starch hydroxyl group. Crosslinking was then achieved by the addition of 1,1′‐(methylene‐di‐4,1‐phenylene) bismaleimide to the furan‐grafted starch in solution (dimethylsulfoxide) and in the molten state during conventional extrusion. The materials were characterized by Fourier transform infrared and 1H NMR spectroscopy. The thermoreversible reaction was assessed by viscosity measurement and 1H NMR, for the system in dimethylsulfoxide, and by solubility tests, hot‐pressing experiments and dynamic mechanical analysis measurements for the extruded product. The crosslinked product showed a higher storage modulus and water resistance than its non‐crosslinked counterpart, opening novel opportunities to widen the range of TPS applications. © 2015 Society of Chemical Industry