**Electrically Conductive Nanocomposites Composed of Styrene–Acrylonitrile Copolymer and rGO via Free-Radical Polymerization**

#### **Eun Bin Ko <sup>1</sup> , Dong-Eun Lee 2,\* and Keun-Byoung Yoon 1,\***


**\*** Correspondence: dolee@knu.ac.kr (D.-E.L.); kbyoon@knu.ac.kr (K.-B.Y.)

Received: 13 April 2020; Accepted: 26 May 2020; Published: 27 May 2020

**Abstract:** The polymerizable reduced graphene oxide (mRGO) grafted styrene–acrylonitrile copolymer composites were prepared via free radical polymerization. The graphene oxide (GO) and reduced graphene oxide (rGO) was reacted with 3-(tri-methoxysilyl)propylmethacrylate (MPS) and used as monomer to graft styrene and acrylonitrile on its surface. The successful modification and reduction of GO was confirmed using Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analyzer (TGA), Raman and X-ray diffraction (XRD). The mRGO was prepared using chemical and solvothermal reduction methods. The effect of the reduction method on the composite properties and nanosheet distribution in the polymer matrix was studied. The thermal stability, electrical conductivity and morphology of nanocomposites were studied. The electrical conductivity of the obtained nanocomposite was very high at 0.7 S/m. This facile free radical polymerization provides a convenient route to achieve excellent dispersion and electrically conductive polymers.

**Keywords:** polymerizable reduced graphene oxide; in situ polymerization; electrical conductivity; dispersion of 2D nanosheets
