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In this work, we report the preparation of poly(vinylidene fluoride)/poly methylmethacrylate (PVDF/PMMA)/graphene polymer blend nanocomposites via synthesis of PMMA/graphene as a masterbatch through in situ polymerization. The PMMA/graphene masterbatch compounded with PVDF by solution mixing in different ratios. The compounding was followed by solution casting to form polymer blend nanocomposites. Solution cast films were subjected to thermal treatments at three different temperatures. The crystalline structure of thermally treated samples was studied with X‐ray diffraction spectroscopy and Differential Scanning Calorimetric (DSC) analysis. Results indicated PMMA chains persuade the β crystalline form in PVDF but cannot stabilize them in elevated temperature; however, graphene sheets due to restricting effect on TT conformation chains are able to stabilize them. DSC data revealed the graphene sheets can increase the crystallinity of PVDF and also act as nucleating agents. Transmission Electron Microscopy demonstrated coexistence of the different stacking orders of graphene sheets in both masterbatch and polymer blend nanocomposite. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers

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In this work, we report the preparation of graphene nanoplatelet which covalently functionalized with PMMA chains by introduction of vinyl groups onto graphene surface through simple esterification reaction between hydroxyl groups of graphite oxide and methacrylic anhydride. The synthesis is followed by in-situ polymerization with MMA monomers. The structural properties were characterized with X-ray diffraction spectroscopy (XRD) and scanning electronic microscopy (SEM) that showed the crystalline graphite is converted to individual layers during the synthesis steps. The grafting of PMMA chains was monitored with IR spectroscopy (FT-IR) and thermogravimetric analysis (TGA). The TGA results revealed 40% wt of PMMA chains chemically grafted onto graphene surface. Significant increase in glass transition temperature (T g ) and existence of polymer chains in two positions (physically absorbed and chemically grafting onto graphite surface) are indicated by differential scanning calorimetric (DSC) analysis.

AC electrical properties of sandwich devices composed of thermally evaporated thin lms of copper phthalocyanine (CuPc) with aluminum and gold electrodes (Al/CuPc/Au) are investigated over frequency (f ) range of 10 2 10 5 Hz and temperature range of 293453 K. Morphology of the samples was studied via eld emission scanning electron microscope images and X-ray diraction micrographs. The X-ray diraction micrograph indicates the conguration of α-CuPc with the (510) plane as the preferred orientation. UVVis absorption spectrum was analyzed and the optical band-gap energy of CuPc thin lm was determined to be 2.81 ± 0.01 eV. Capacitance increased with increasing temperature especially for f = 10 2 Hz. Loss factor decreased considerably with increasing frequency to a minimum value at about f = 10 4 Hz and increased afterwards. Capacitance is generally independent of frequency for T ≤ 413 K; however it decreases remarkably with increasing frequency for T > 413 K. The conductivity increases quite noticeably with increasing frequency particularly for T ≤ 413 K. The AC electrical characteristics are in good agreement with Goswami and Goswami model. According to our data, at high temperatures, the band theory is applicable in describing the conduction process, whereas hopping mechanism is dominant at low temperatures.