Effect of Filler Morphology on the Electrical and Thermal Conductivity of PP/Carbon-Based Nanocomposites

Marta Zaccone,Luigi Torre,Marco Monti,Alberto Frache,Ilaria Armentano

doi:10.3390/jcs5080196

Abstract

In this paper, we studied the effect of different carbon-based nanostructures on the electrical and mechanical properties of polypropylene (PP) nanocomposites. Multi-walled carbon nanotubes (MWCNT), expanded graphite (EG), and two different carbon black nanoparticles (CB) have been dispersed at several weight contents in the polymer matrix through a melt extrusion process. The produced nanocomposites have been used to obtain samples for the characterization by injection molding. The dispersion of the nanoparticles in the matrix has been evaluated by scanning electron microscopy (SEM) analysis. The electrical characterization has been performed both in DC and in AC configuration. The mechanical properties have been evaluated with both tensile test and impact strength (Izod). The thermal conductivity has been also evaluated. As a result, MWCNTs are the nanoadditive with the lowest electrical percolation threshold. This allows MWCNT nanocomposite to drastically change the electrical behavior without a significant embrittlement observed with the other nanoadditives. However, CB with the lowest surface area allows the highest conductivity, even though at a high particle content. EG has a limited effect on electrical properties, but it is the only one with a significant effect on thermal conductivity.

Highlights

In recent years, the interest in electrically conductive polymer nanocomposites has significantly increased, due to the importance of such polymers in the digitalization process, which is affecting our society, especially for what concerns the manufacturing of smart electronic devices [1]
We report a comparative study on the effect of different carbon nanostructures on the electrical, thermal conductivity, and mechanical properties of the PP nanocomposites in which they are embedded
All the tested carbon nanostructures show high thermal resistance with the peak of the derivative weight loss (DTG) higher than 500 ◦C. This peak increases from Multi-walled carbon nanotubes (MWCNT) (611 ◦C) to CB65 (681 ◦C), to Carbon black nanoparticles (CB)-770 (744 ◦C) and to expanded graphite (EG) (788 ◦C)

Summary

Introduction

The interest in electrically conductive polymer nanocomposites has significantly increased, due to the importance of such polymers in the digitalization process, which is affecting our society, especially for what concerns the manufacturing of smart electronic devices [1]. Carbon-based nanoadditives represent one of the most important families to change the electrical behavior of the polymers in which they are embedded [2,3,4,5]. They can be exploited for a variety of industrial applications such as electrostatic discharge [6,7], sensors, and electromagnetic interference (EMI) shielding devices [8,9,10,11,12]. Carbon black nanoparticles (CB), with all dimensions in the nano-scale, are the most used additive to make polymers conductive [3,13,14]. Carbon nanotubes (CNTs), due to their chain-like structure, are able to form a conductive pathway within the polymer matrix, which is typically more effective if compared with the ones produced by other additives [5,20,21,22]

Methods

Results

Conclusion