Positive Temperature Coefficient (PTC) Evolution of Segregated Structural Conductive Polypropylene Nanocomposites with Visually Traceable Carbon Black Conductive Network

Abstract

Electrically conductive carbon black (CB)/polypropylene (PP) nanocomposites with a segregated structure are fabricated by localizing CB particles at the interfaces among the PP granules. Interesting double‐peak positive temperature coefficient (PTC) effect when exposed to temperature field is observed and ascribed to the breakage of unique segregated conductive network due to the volume expansion stemming from the crystal melting of interfacial PP and the bulk PP matrix. With extending thermal treatment time, the PTC intensity first increases and then decreases obviously. Long treatment time is required for the composites with high CB loadings to reach the PTC intensity maximum value. This phenomenon is attributed to the evolution of segregated microstructure during the thermal treatment, which is traced visually in situ through an optical microscope (OM). The diffusion due to the concentration gradient and the subsequent aggregation of CB particles lead to this behavior. A model based on the OM observation is proposed to reveal the origin of this novel resistivity‐temperature behavior.

Flexible conductive Ag nanowire/cellulose nanofibril hybrid nanopaper for strain and temperature sensing applications

“…As a result, it displayed a 4.7% resistance response at a strain of 2.9% and excellent reproducibility at a strain of 2%. Furthermore, the application of CPCs (carbon black (CB)/polyamide 6 (PA6)/ultra high density polyethylene [40], CB/polypropylene [41], graphene/PA6/ultrahigh molecular weight polyethylene [42], etc.) in the fields of temperature detection was also widely investigated.…”

Endowing Acceptable Mechanical Properties of Segregated Conductive Polymer Composites with Enhanced Filler-Matrix Interfacial Interactions by Incorporating High Specific Surface Area Nanosized Carbon Black

“…Compared to the loosely stacked l-CCB network, while the strong Van der Waals forces of h-CCB particle are easy to aggregate each other, and gradually form a denser and denser developed conductive network with increasing h-CCB concentrations. This may be attributed to the strong mechanical interlocked interactions of h-CCB particles and UHMWPE matrix, and the Brownian motion of CCB particles in the UHMWPE melt creates the distinctly interfacial transition layer and strongly interfacial adhesion, forming the densely stacked conductive network [ 35 ]. To sum up, the optical microscopy observations intuitively confirm the formation of high-quality segregated conductive networks.…”

“…However, among these methods in enhancing the filler-matrix, interfacial interactions is relatively complicated for the practical production process. Thus, for CPCs with strong interface adhesion and small defects, whether they can simply employ low-cost and high-electrically conductive nanostructured carbon fillers for developing EMI shielding materials has become a very perspective research hotspot [ 35 , 36 ].…”

A Review on the Thermal Hazards of the Lithium-Ion Battery and the Corresponding Countermeasures

“…Besides, the PTC based on materials are also widely used among LIBs, whose resistance increases dramatically in response to the rapid rise of temperature [194][195][196][197][198][199]. For example, if a large current flows across the PTC element, its temperature increases abruptly, while the PTC works.…”