Thermal degradation kinetic, electrical and dielectric behavior of brush copolymer with a polystyrene backbone and polyacrylate-amide side chains/ nanographene-ﬁlled composites Fatih Biryan, Kadir Demirelli * Faculty of Science, Department of Chemistry, University of Firat, 23169 Elazig, Turkey article info Article history: Received 24 November 2018 Received in revised form 16 February 2019 Accepted 8 March 2019 Available online 9 March 2019 Keywords: Electrical properties Kinetic Brush copolymer Nanographene Composite abstract A brush copolymer having polystyrene backbone and ﬂexible PA-amide (polyacrylate-amide) brushes that exhibit thermoplastic elastomer property was synthesized, and brush copolymer composites with nanographene in various ratios were prepared. The thermal properties of the macroinitiator, brush copolymer and composites were investigated using differential scanning calorimeter (DSC) and ther- mogravimetric analysis (TGA). The activation energy (E a ) of thermal decomposition of brush copolymer/ 6 wt% nanographene was estimated by the Flynn-Wall-Ozawa method, and the average activation energy value for the 0.1e0.7 conversion was estimated as being 141.7 kJ/mol. Electrically conducting nanographene-based brush copolymer composites were produced. DC and AC electrical conductivity and dielectric properties of permittivity of nanographene-based brush copolymer composites were investi- gated. Further, the activation energy proﬁle of different nanographene/brush copolymer composites were determined by measuring DC conductivity of individual composite materials. A heterojunction diode made from the polymer nanographene composites were magniﬁed on a p-type Si substrate using a hydro/solvo thermal method. The polymer composite/p-Si thin ﬁlm heterojunction diode properties were studied using current-voltage (I-V) and capacitance-voltage (C-V) analysis. © 2019 Elsevier B.V. All rights reserved. 1. Introduction Most polymers have useful dielectric and high resistivity prop- erties. Polymers can be used for corrosion protection in electronic devices and as insulators. On the other hand, electrical properties of polymers are useful in photonic and optoelectronic applications. Composite developments are necessary imperative concerns for the industrial applications of synthetic polymers. Although ﬁlled- based polymer composites are prepared by mixing and other methods, the mussel-inspired chemistry is also a useful method for the preparation of polymer nanocomposites for universal adhesion properties of various materials and surfaces. The mussel-inspired chemistry is a promising method for producing very effective nanocomposites in terms of environmental and industrial appli- cations [1]. Dielectric properties of materials are very important in terms of their industrial applications. These features provide useful information for improving product quality. Therefore, there is an increasing interest in improving composite-based synthetic poly- mers. The electrical and optical behavior of polymer composites are important in addition to their thermal properties and physical behavior. The distribution of nanographene in different polymer matrices created a new polymer nanocomposite class [2]. The improvement of nanocomposite materials is important in terms of extending their applications scopes. A large number of reports have been made not only on the high electrical conductivity of graphene at 25  C, but also on the potential of extending their applications, such as for use as transparent electrodes, nano-sensors and con- ducting composites [3]. When nanographene is dispersed within a polymer in presence of organic solvent, its properties remain important when mixing with polymer matrices for the eventual improvement of thermal behaviors and physical properties. The compatibility of graphene with some copolyesters have been investigated and it was noted that the compatibility was enhanced with increasing content of ester moieties in the polyester. This compatibility was veriﬁed by scanning electron microscopy (SEM). In polymer composites, graphene effectively enhanced the perfor- mance of matrix polymers in respect to the electrical, thermal, gas barriers properties and produced nanocomposite polymeric * Corresponding author. E-mail address: kdemirelli@ﬁrat.edu.tr (K. Demirelli). Contents lists available at ScienceDirect Journal of Molecular Structure journal homepage: http://www.elsevier.com/locate/molstruc https://doi.org/10.1016/j.molstruc.2019.03.026 0022-2860/© 2019 Elsevier B.V. All rights reserved. Journal of Molecular Structure 1186 (2019) 187e203