Positive Temperature Coefficient and Electrical Conductivity Investigation of Hybrid Nanocomposites Based on High‐Density Polyethylene/Graphene Nanoplatelets/Carbon Black

Abstract

Hybrid nanocomposites of high‐density polyethylene have been prepared via the melt‐mixing method in the presence of different amounts of graphene nanoplatelets (GNPs) and conductive carbon black (CB). The electrical conductivity, positive temperature coefficient (PTC), and the correlation between crystallinity and electrical conductivity of hybrid nanocomposites are investigated to study the effect of crystallinity on electrical conductivity. The samples are characterized using differential scanning calorimetry (DSC), scanning electron microscopy (SEM), X‐ray diffraction (XRD), and electrical resistivity. SEM micrographs reveal good distribution of CB and GNPs in nanocomposites. According to DSC and XRD results, the crystallinity of samples decreases by the addition of CB and GNP. The electrical conductivity of all the samples increases, whereas in the sample 16% of CB and 1% of GNP electrical conductivity decrease due to GNP acting as a heterogeneous nucleating agent and the numerous incomplete and small crystals formation. The highest electrical conductivity (1.46×10−4 S cm−1) is obtained in the sample high‐density polyethylene (HDPE)/CB18/GNP1, which shows high increment in the PTC curve in the range of 105−120 °C. Also, repeatability and reversibility of PTC in this sample show good potential for use in different applications such as thermistors, temperature sensors, and self‐regulating heaters.

Antistatic and antimicrobial packaging of PLA/PHBV blend‐based graphene nanoplatelets nanocomposites

“…The interplanar spacing of GNP (d 002 ) was calculated using Bragg's equation (Equation ()): Where θ is the diffraction angle of the peak referring to the (002) plane, and λ is the x‐ray wavelength. The average size and thickness of the crystals formed by stacking the GNP planes were calculated by the Scherrer Equation (Equation ()): Where D 002 represents the dimension of the nanoparticle in the diffraction direction, K is a constant equal to 0.9 due to the graphitic planar structure 18 and B 002 is the width at half height of the diffraction peak in radians. The number of graphene layers of the GNP was calculated by Equation (). …”

“…Where D 002 represents the dimension of the nanoparticle in the diffraction direction, K is a constant equal to 0.9 due to the graphitic planar structure 18 and B 002 is the width at half height of the diffraction peak in radians.…”

Achieving superior pyroresistive reproducibility at HDPE/PVDF composites with tailored conductive phase size

“…For ensuring the practicability and security of PTCs by improving PTC reproducibility, great amounts of efforts have been employed, including modification of conductive fillers and hybrids of different conductive fillers. [26][27][28][29][30] Wu and coworkers modified CB by oleic acid and introduced it into octadecane for room temperature thermal regulation. 31 The PTC reproducibility of composites is hence improved as the self-aggregation of fillers is restricted by developing the compatibility between filler and matrix to some extent.…”

Polymer Composites with Self-Regulating Temperature Behavior: Properties and Characterization

“…Due to their properties, these materials exhibit high functionality and smartness in various technical applications comprising conductive coatings, electromagnetic shielding, electronic packaging flexible displays, sensors, etc. [6][7][8][9][10]. Various conductive powders or fiber materials/nanomaterials [7,11,12] can be used as conductive fillers, the carbon ones being of great interest due to low cost, good electrical properties, acceptable compatibility with polymer matrix, low density, and corrosion resistance.…”

“…Various conductive powders or fiber materials/nanomaterials [7,11,12] can be used as conductive fillers, the carbon ones being of great interest due to low cost, good electrical properties, acceptable compatibility with polymer matrix, low density, and corrosion resistance. Carbon black [8,13,14], carbon fibers [15,16], graphite [17]), graphene [9,18], reduced graphene oxide [19], CNT [11,16,18], and other carbon materials were studied in order to obtain adequate properties for a wide range of applications. Among them, the composites exhibiting so-called Positive Temperature Coefficient (of resistivity) effect, abbreviated PTC [1] or PTCR [13], are of special interest for specific applications claiming self-limitation (of current) or switching (conductive/resistive) behaviors, such as self-regulating heating elements, current or voltage protections or temperature sensors [15,17].…”