Tensile modulus modeling of carbon black/polycarbonate, carbon nanotube/polycarbonate, and exfoliated graphite nanoplatelet/polycarbonate composites

Abstract

Conductive fillers are often added to thermoplastic polymers to increase the resulting composite's electrical conductivity (EC) which would enable them to be used in electrostatic dissipative and semiconductive applications. The resulting composite also exhibits increased tensile modulus. The filler aspect ratio plays an important role in modeling composite EC, and tensile modulus. It is difficult to measure the filler aspect ratio after the manufacturing process (often extrusion followed by injection molding) in the composite, especially when nanomaterials are used. The EC percolation threshold is a function of the filler aspect ratio; hence, knowledge of this percolation threshold provides a means to extract the filler aspect ratio. In this study, the percolation threshold of the composite was determined from EC measurements and modeling, which in turn was used to determine the filler aspect ratio for tensile modulus modeling. Per the authors' knowledge, this approach has not been previously reported in the open literature. The fillers; carbon black (CB: 2-10 wt %), multiwalled carbon nanotubes (CNT: 0.5-8 wt %), or exfoliated graphite nanoplatelets (GNP: 2-12 wt %); were added to polycarbonate (PC) and the resulting composites were tested for EC and tensile modulus. With the filler aspect ratio determined from EC values for CNT/PC and GNP/PC composites, the three-dimensional randomly oriented fiber Halpin-Tsai model accurately estimates the tensile modulus for the CNT/PC composites and the Nielsen model predicts the tensile modulus well for the CB/PC and GNP/PC composites.

Synergistic effects of carbon nanotubes and exfoliated graphite nanoplatelets for electromagnetic interference shielding and soundproofing

“…For this work, the electrical resistivity was measured using the four‐point probe method. Figure shows the volume resistivity of various types of polymer/nanofiller composites . Because the electrical properties of the composites reported herein were better than those reported for other composites, it was expected that they would also have good EMI SE.…”

Effects of Graphene Nanoplatelets and Multiwall Carbon Nanotubes on the Structure and Mechanical Properties of Poly(lactic acid) Composites: A Comparative Study

“…Last decade, many scientific efforts have been made for the synthesis of multifunctional polymer nanocomposites that take advantage of the unique mechanical and structural properties of new graphitic forms as graphene (GNPs) and multiwall carbon nanotubes (MWCNTs) [1][2][3][4][5]. There are a lot of studies on carbon composites based on a wide range of polymers, reported in the literature as polycarbonate [6], nylon [7], poly(methyl methacrylate) [8], epoxy resin [9], poly(vinyl alcohol) [10], polystyrene [11], polycaprolactone [12], poly(propylene) [13], and poly(lactic acid) [14,15]. One of the main parameters that influences the composite properties is the distribution/dispersion of the carbon nanofillers in conjunction with their weight percentage loading in the polymer matrix [16,17].…”

A study on the effects of graphene nano-platelets (GnPs) sheet sizes from a few to hundred microns on the thermal, mechanical, and electrical properties of polypropylene (PP)/GnPs composites

“…However, it has been considered extremely challenging to commercialize advanced products fabricated with graphene due to inability in mass production of high-quality graphene at low cost. Recently, graphene nano-platelets (GnPs) have been recognized as an inexpensive alternative to graphene due to its possibility of mass production at low cost [10,11]. GnPs are layered graphene nano-crystals in the structure of platelets stacked by van der Waal's forces [12].…”