Yongqiang Guo, Genjiu Xu,a Xutong Yang, Kunpeng Ruan, Tengbo Ma, Qiuyu Zhang, Junwei Gu*, Yalan Wu*, Hu Liude and Zhanhu Guo*. Significantly enhanced and precisely modeled thermal conductivity in polyimide nanocomposites with chemically modified graphene via in situ polymerization and electrospinning-hot press technology. Journal of Materials Chemistry C, 2018, 6: 3004-3015.

Abstract

Both aminopropylisobutyl polyhedral oligomeric silsesquioxane (NH₂-POSS) and hydrazine monohydrate were utilized to functionalize graphene oxide (GO), and to obtain chemically modified graphene (CMG), which was then used for preparing thermally conductive CMG/polyimide (CMG/PI) nanocomposites via a sequential in situpolymerization and electrospinning-hot press technology. NH₂-POSS molecules were grafted on the GO surface, and CMG was obtained by the reaction between NH₂-POSS and GO. The thermal conductivity coefficient (λ), glass transition temperature (T_g) and heat resistance index (THRI) of the prepared CMG/PI nanocomposites were all increased with increasing the CMG loading. The λ value of the CMG/PI nanocomposites with 5 wt% CMG was significantly improved to 1.05 W m^?1 K^?1, about 4 times higher than that of the pristine PI matrix (0.28 W m^?1 K^?1). The corresponding Tg and THRI values were also increased to 213.0 and 282.3 °C, respectively. Moreover, an improved thermal conductivity model was proposed and predicted the λ values of the nanocomposites more precisely than those obtained from the typical Maxwell, Russell and Bruggemen classical models.