*1.2.1 Thermal properties of graphene/polymer composites*

Vibrating lattice is the key upon which material's thermal conductivity depends on. Graphene ensures a material to be thermally conductive and stable, because it exhibits excellent thermal conductivity at room temperature ( − − ∼ 1 1 3000*Wm K* ). Therefore it imparts substantially in the improvement of thermal properties. Thermally less interface resistance, stiffness and the planar geometry of graphene are the major factors yielding remarkable thermal properties (1266 Epoxy/ Graphite). Graphene's utility as transparent conductors attributes to its peculiar characteristics like higher conductivity, and incorporation towards ceramics and polymers [13]. On the contrary, thermal properties are suffered by graphene's orientation and aspect ratio.

#### *1.2.2 Mechanical properties of graphene/polymer composites*

Recent discoveries introduced fascinating insights of material science as graphene proved experimentally as nanomaterial. Graphene constitutes remarkable elastic modulus (125 GPa) and intrinsic strength ( ∼1.0*TPa* ). Scientists after having a comprehensive overview of all intrinsic properties of graphene, are now able to manufacture graphene-filled led polymer composites with desired properties. However, other milestones for the betterment include reinforcement phase aspect ratio, distribution in the host matrix, interface bonding, and the reinforcement phase concentration. Noticeable thing is that the increment in properties of polymer matrix attains at low filler loading [14].

#### *1.2.3 Electrical properties of graphene/polymer composites*

Electrical conductivity for graphene is its notable attribute, among all physical properties. Conductive graphene itself raises the possibility for elevation in electrical conductivity, when it comes to be utilized as fillers along with insulating polymer matrix. When loading fraction touches certain limit, particularly at a stage of percolation threshold, electrical conductivity increases rapidly right after the formation of network by filler. Electrical conductivity influences by the concentration of fillers as well as by percolation threshold. Conduction takes place through tunneling in polymer layers, so there is no such need for the filler to be in contact with the current flow directly. The limiting factor in thermal conductivity for polymer composites is ultimately the tunneling resistance [15]. Graphene in its other variant generally named as pristine graphene have much higher electrical conductivity, yet mechanical exfoliation scheme for its production on a bigger scale reduces its utility [16].
