Study on the Preparation and PTC Behavior Of Graphene/Polyvinylidene Fluoride Composites

Liang Hu Hong,Yue Zhao Ming,Guang Xiao Li,M Jawaid,El-R Kenawy

doi:10.1051/matecconf/20166706004

Abstract

Graphene/Polyvinylidene fluoride (PVDF) conductive composite materials were prepared by co-solvent method. GO were stably dispersed in H 2 O/N, N-dimethylformamide (DMF) (1∶9, volume ratio) medium. After sonication, a clear stable brown solution was prepared without any visible aggregation. Changes in the internal structure and crystallization properties is demonstrated of the graphene/PVDF composites by scanning electron microscopy (SEM) and differential scanning calorimetry discussion(DSC).It was shown that in the 1:9 mixed solvent of H 2 O/DMF can improve GO concentration which increased 2.98 times and can form a homogeneous stable solution. The resistance decreases with temperature, indicating an NTC behavior and the room-temperature resistivity downward trend during the thermal cycles.

Highlights

Polymer-based PTC materials are a kind of thermo-sensitive materials which are prepared with the polymer as the substrate and the addition of some conductive fillers such as carbon black, carbon fiber, and metal powder etc
Through the Atomic force microscope (AFM) analysis of GO, we found that the thickness of the GO film is 0.814nm less than 1nmFig.1b, which indicates that the GO can be fully stripped in the mixed solvent of H2O/dimethyl formamide (DMF)
By researching the GO dispersion properties of different solvent systems, we found that in the mixed solvent system of H2O/DMF the introduction of H2O improves the dispersion ability(Fig.1c) .The concentration of GO in the mixed solvent of H2O/DMF is 1.94mg/ml, which increases by 2.98 times compared with the concentration which is 0.65 mg/ml in the single solvent of DMF

Summary

Introduction

Polymer-based PTC materials are a kind of thermo-sensitive materials which are prepared with the polymer as the substrate and the addition of some conductive fillers such as carbon black, carbon fiber, and metal powder etc. Due to the strong van der Waals force of graphene layers, the reunite and dispersed problems remain to be solved ofgraphene in the preparation process of polymer composites. Recent studies have shown that RGO can have an ultrasonic exfoliation in polar solvents such as dimethyl formamide (DMF), N-methyl pyrrolidone (NMP)[5,6]. It is not suitable for the preparation of polymer nanocomposites due to the low concentration and can't steady state exist of RGO.So aiming at the above problems, we put forward using H2O and DMF mixed solvent,significantly improved the dispersion performance of RGO. At the same time RGO/PVDF composites were prepared by thermal reduction process and its PTC behavior was studied

Experimental Procedures

Preparation and characterization of composite materials

Conclusion