▎ 摘　　要

We reported on an ultratough, ductile, castor oil-based, hyperbranched, polyurethane (HPU) nanocomposite using functionalized reduced graphene oxide (f-RGO) as a reactive chain extender as well as a nano-reinforcing material. The functionalization of phytoextract-reduced graphene oxide (RGO) was achieved by reacting with 2,4/2,6-toluene diisocyanate, followed by reacting with 1,4-butanediol. Functionalization (hydroxyl group-terminated urethane linkage) in f-RGO was confirmed by FTIR and XRD studies. The obtained nanocomposite demonstrated tremendous enhancements of tensile strength (525%), modulus (42 folds), and toughness (18 folds) after incorporation of 2 wt % of f-RGO in HPU. Most surprisingly, elongation at break of the nanocomposites was enhanced from 710% to a maximum of 1656%. On other hand, the HPU nanocomposite with RGO was unable to demonstrate improved properties similar to those of HPU/f-RGO nanocomposites. The HPU/f-RGO nanocomposite also demonstrated good thermal stability and excellent electrical conductivity with an enhancement of almost 10 orders of magnitude at 2 wt % f-RGO. The effective and promising technique presented here paves the way to graphene-based polymer nanocomposites with excellent performance and novel functionalities.