Graphene oxide was chemically synthesized, functionalized with dodecyl amine and then reduced. The graphene oxide was also thermally reduced to obtain graphene. Different analyses were employed to structural characterization of the materials.

Relationship between rheology, morphology, and electrical conductivity of the poly(vinylidene fluoride)/polyethylene/graphene nano-platelets ternary system (PVDF/PE/GnP) were investigated. All the blend nanocomposites were prepared via a two-step melt mixing method. GnP (0.75 and 1.5 wt %) was first compounded with PVDF and then the resulted premixtuers were melt mixed with PE to achieve the desired compositions. The corresponding reference nanocomposites and filler-less blends were also prepared. Effect of an interfacial agent (PEMA; maleic anhydride grafted polyethylene) was also studied in this work. The results of rheological analysis in conjunction with the Raman spectroscopy experiments revealed that GnP had higher affinity to PVDF than PE, which in turn led to creation of conductive networks of GnP (1.5 wt %) in PVDF matrix exhibiting the electrical conductivity of about 10 22 (S/cm). Double percolated micro-structure was predicted for the PE/PVDF 40/60 (wt/wt) blend containing low GnP content (0.9 wt %) and confirmed via direct electron microscopy and conductivity analysis. Using 5 wt % of the PEMA reduced the conductivity to 10 25 (S/cm) and further increase in PEMA content to 10 wt % led to non-conductive characteristics. The latter was attributed to the migration of GnP from the PVDF phase to PE/PEMA phase and hence disturbance of double percolated micro-structure. V C 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46333.

Effect of graphene nano-platelets (GnP) on the crystalline structure of poly(vinylidene fluoride)/polyethylene (PVDF/PE) blends was studied. The PVDF/GnP were melt compounded with PE and/or PE/PE-g-MA mixture to obtain the desired compositions. Alteration in polymorphism of the PVDF component in the blends and in the presence of GnP, was evaluated employing different analyses. The flow-induced crystallization experiments were conducted under oscillating rheometry at vicinity of crystallization temperature of the PVDF. The results of XRD and FTIR analysis indicated that the charge-transfer C F bonding interaction between the PVDF chains and basal plane of GnP layers led to alteration of polymorphism of PVDF from α form to α-, γ-, and β-phase crystals. Selective localization of the GnP in PVDF component increased the C F bonding interaction and decreased the hydrogen bonding between PVDF and PE chains, respectively. In the presence of PE-g-MA, the hydrogen bonding promoted and the C F bonding interaction decreased leading to predominance of the α-form crystal formation in the PVDF phase. While the GnP acted as nucleating agent in PVDF component under quiescent conditions, it had negative effect on row nuclei under flow conditions. The structures originated from row-nuclei and GnP surfaces, led to formation of "shish-kebab" and "oriented lamella" morphologies, respectively.

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