Preparation and properties of graphene oxide/polyimide composites by in situ polymerization and thermal imidization process

Graphene oxide/polyimide (GO/PI) composites with different loadings of GO were prepared by in situ polymerization and solution blending method. By adding GO, the mechanical, electrical, and thermal properties of composites could be improved. The tensile strength of GO/PI composite with 3.0 wt% GO loading was up to 137.8 MPa, 75.5% higher than that of a pure PI. Besides, the electrical and the thermal conductivities increased with the increase of GO contents. An electrical conductivity value of 5.38 x 10(-5) S m(-1) and a thermal conductivity value of 0.10 W m(-1) K-1 for GO/PI composites prepared via in situ polymerization at GO content of 3.0 wt% were achieved. The results indicated that in situ polymerization was able to make GO a better dispersion in the polymer matrix. Furthermore, the behavior of GO under the thermal imidization temperature was also discussed. The experimental results showed that GO could be partially reduced to graphene during the thermal curing process. Above works are conducive to the understanding of the effect and transformation of GO in the preparation process of graphene-based composites.