Carbon quantum dots enhanced graphene/carbon nanotubes polyurethane hybrid nanocomposites

The outstanding dispersion of nanofillers in polymer matrices is needed to fabricate high-performance nanocomposites. Herein, three-dimensional nanostructures of graphene nanoplatelets (GNP) and carbon nanotubes (CNT) with enhanced dispersion quality accompanied by carbon quantum dots (CQDs) are prepared within the polyurethane (PU) matrix. CQDs and nitrogen-rich carbon quantum dots (N:CQD) were facilely synthesized using a domestic microwave oven within minutes to improve the interfacial bonding of carbon nanofillers with the polymer matrix, which positively affected the final performance of nanocomposites. Being highly prone to forming bindings with other carbon nanofillers, CQDs restrain graphene stacking and CNT bundling, leading to considerably improving the dispersion quality in the PU matrix to enhance desired properties. PU with binary CNT/CQD and ternary GNP/CNT/CQD nanocomposites revealed higher mechanical properties and thermal stability, in which tensile strength and elastic modulus of PU enhanced up to about 54% and 71% at a very low concentration of 0.25 wt%, respectively.