Thermal conductivity of GP/ZnO@CNTs nanocomposites improved greatly by orientation of CNTs under shear field

The thermal conductivity (TC) of gutta-percha, zinc oxide, and carbon nanotubes nanocomposites (GP/ZnO@CNTs) is improved greatly by the oriented CNTs, which is induced by shear field of the capillary rheometer. Furthermore, the effects of shear rate and temperature on the orientation of CNTs and the TC of the nanocomposites are investigated. The results of Raman show that the degree of orientation of CNTs increases with the increment of shear rate and/or temperature, which greatly improves the thermal conductance of the nanocomposites when the orientation degree is equal to 10.8. Compared with the GP/ZnO@CNTs nanocomposites with random CNTs, the highest TC of GP/ZnO@CNTs nanocomposites with oriented CNTs is increased by 81.2%, which is up to 2.50 W m(-1)K(-1).