Effect of Chemical Modification of Graphene on Mechanical, Electrical, and Thermal Properties of Polyimide/Graphene Nanocomposites

Abstract

Chemically modified graphene sheets were dispersed in a high-performance polyimide (PI) matrix using polyamic acid (PAA)/graphene nanocomposite as a precursor. PI nanocomposite films with different loadings of graphene sheets were prepared by thermal imidization of the as-prepared PAA/graphene nanocomposites. Graphene oxide (GO) synthesized by Hummer's method was chemically reduced with various reducing agents to produce reduced GOs (rGOs). The incorporation of only 5 wt% GO resulted in an ~12-fold and ~18-fold increase in the tensile strength and tensile modulus of PI, respectively, while the PI/rGO nanocomposites were found to have relatively inferior tensile properties. The superior mechanical properties of the PI/GO nanocomposites were attributed to the good dispersion and effective stress transfer between the polymer and GO sheets, as evidenced by the results from X-ray diffraction (XRD) and morphological studies. Furthermore, the PI/GO nanocomposites exhibited higher loading capacity than PI/rGO. The thermo-oxidative stability of PI was also remarkably improved with the addition of both GO and rGOs, but rGOs had a more pronounced effect. The electrical conductivity of PI/rGO nanocomposites was higher than that of PI/GO, suggesting restoration of the graphene basal plane upon the reduction of GO. The highest electrical conductivity was achieved for the l-ascorbic acid reduced GO-reinforced PI nanocomposites.

Hybrid materials based on polyethylene and MCM-41 microparticles functionalized with silanes: Catalytic aspects of in situ polymerization, crystalline features and mechanical properties

“…Examples in literature exhibit significant improvements in mechanical, electrical, biocidal and thermal properties [1][2][3][4][5][6][7], which are difficult to be achieved using conventional fillers [8,9]. An aspect of significant impact, mainly in weight and cost, is the low reinforcement loadings required (typically inferior to 8 wt.%) to attain a noteworthy enhancement in properties.…”

Synthesis, Properties and Potential Applications of Porous Graphene: A Review

“…This decrease in the tensile properties might be due to the increasing aggregation tendency of the GO layers forming some defects in the nanostructure of the nanocomposites. As regard the PI/rGO nanocomposites, these nanocomposites showed significant enhancement in both the tensile strength and tensile modulus when the rGOD content increased from 1 wt% to 5 wt%, whereas the tensile properties decreased when the filler content is increased to 7 wt%, with a similar trend observed for the GO filler [41]. As the porous graphene is still in its infant stage, the further work is needed to elucidate relative molecular structures, such as, it is unclear the edge state of porous graphene, is in an armchair or a zigzag configuration.…”

Manipulating selective dispersion of reduced graphene oxide in polycarbonate/nylon 66 based blend nanocomposites for improved thermo-mechanical properties

“…44 However, in binary blend (PN), the characteristic peaks of PC and nylon merge together and can be observed as a broad peak, corresponding to PC along with a less intense sharp peak corresponding to nylon 66. [43][44][45] The broadness of the peak indicates the amorphous nature of the blend. Absence of molecular interaction between PC and nylon is the case of neat blend (as discussed in FTIR section), decreased crystallinity of the blend attributed to penetration of PC chains into a nylon matrix which can disturb the hydrogen bonding interaction within the nylon chains and hence diminished mechanical properties which has also reported in literature.…”