Surface Functionalization of Graphene Oxide with Polymer Brushes for Improving Thermal Properties of the Polymer Matrix

Shuangshuang Wang,Guang Li,Xiangcai Ge,Lin Chen,Yuchao Li,Wei Li,Houfang Chi,Gyorgy Szekely

doi:10.1155/2021/5591420

Abstract

In this work, polymethyl methacrylate (PMMA) and polystyrene (PS) with controlled structures would be grafted on graphene material. The hybrid materials were prepared by coating graphene oxide (GO) with polydopamine (PDA) as a reactive underlayer and reducing agent, subsequently, surface-initiated polymerization of monomers (methyl methacrylate, styrene) based on the activators regenerated electron transfer atom transfer radical polymerization (ARGET-ATRP) technique. The polymer brush-modified graphene materials were then incorporated into the PMMA or PS matrix to get polymer nanocomposites with better thermal properties. The results of Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and thermal gravimetric analysis (TGA) demonstrated that PMMA and PS chains were successfully anchored on the surfaces of functionalized GO sheets. The influence of the grafted polymer brush-modified GO on thermal stability of PMMA and PS was investigated by a simultaneous thermal analyzer. Thermal conductivity of the polymer nanocomposite was determined by a conductive calorimeter. The results showed that thermal stability, glass transition temperature ( T g ), and thermal conductivity of the polymer nanocomposites were obviously improved compared with pure PMMA or PS.

Highlights

Graphene has emerged to be a promising material due to its unique two-dimensional structure and a range of prominent properties
polymethyl methacrylate (PMMA) and PS were grafted from functionalized graphene oxide (GO), which was prepared by PDA noncovalent modification combined with ARGET-atom transfer radical polymerization (ATRP) covalent modification
In the Fourier transform infrared spectroscopy (FTIR) spectrum of reduced graphene oxide (rGO)-g-PMMA, a sharp absorbance peak at 1720 cm1 of the C=O characteristic band of ester groups introduced by grafted PMMA was observed

Summary

Introduction

Graphene has emerged to be a promising material due to its unique two-dimensional structure and a range of prominent properties. Covalent functionalization of graphene with polymer brushes via either “grafting from” or “grafting to” approaches is an effective strategy for surface modification [22,23,24]. Grafting of polymers from solid substrates by the combination of PDA chemistry and ARGET-ATRP has been firstly reported in our previous work [45, 46]. Preparation of grafted polymer-functionalized reduced graphene oxide (rGO) by PDA chemistry and ARGET-ATRP has not been reported by other research groups. PMMA and PS were grafted from functionalized GO, which was prepared by PDA noncovalent modification combined with ARGET-ATRP covalent modification. (BIBB), was coupled onto the surface of rGO/PDA nanosheets to initiate the polymerization of MMA and St by using the ARGET-ATRP technique. Convenient, and green methodology for preparing polymer brush-functionalized rGO, and the polymer-modified rGO could be used as a nanofiller to improve the thermal properties of the polymer matrix

Experimental

Results and Discussion

Conclusions