▎ 摘　　要

Graphene oxide (GO) is reduced in dimethylacetamide by solvothermal reduction to prepare reduced graphene oxide (rGO). The thermal conductivity of rGO has been extremely improved compared with GO. The preparation method of poly amic acid (PAA) solution with rGO is in situ polymerization, then the uniformly dispersed solution of rGO/PAA is acquired. Polyimide (PI) nanocomposite films is prepared by the imidization of rGO/PAA nanocomposites. Transmission Electron Microscope (TEM) clearly shows the bonding of graphene and PI. The temperature of 7% weight loss of nanocomposite films exhibits a considerable increase (similar to 27 degrees C) by adding rGO. The tensile strength of nanocomposite films with 2 wt% rGO increases by 413.67% and the thermal conductivity coefficient increases by 1051.6% in comparison with pure PI films. The alignment of rGO is along the horizontal direction of films with rGO which can improve thermal decomposition temperature and thermal conductivity. Due to the tight bond of PI films and rGO, pulling out rGO needs more work during the stretching process, then the tensile properties of PI films are extremely improved.