Positive/Negative Temperature Coefficient Behaviors of Electron Beam-Irradiated Carbon Blacks-Loaded Polyethylene Nanocomposites

Abstract

Polymer-based materials with positive temperature coefficients (PTC) are regarded as potential candidates for electrical heating elements in a wide range of applications, such as wearable electronics, soft robots, and smart skin. They offer many advantages over ceramic or metal oxide-based composites, including low resistance at room temperature, excellent flexibility and processability, and low cost. However, the electrical resistance instability and poor reproducibility have limited their use in practical applications. In this work, we prepared carbon blacks-reinforced high-density polyethylene nanocomposites (CBs–HDPE) loaded with polar additives (polyols or ionomers), which were subsequently subjected to electron beam (EB) irradiation to explore their PTC behaviors. We found that the EB-treated nanocomposites exhibited PTC behaviors, while the untreated samples showed negative temperature coefficients. Further, EB–ionomer-CBs–HDPE showed the highest PTC intensity of 3.01 Ω·cm, which was ∼35% higher than that of EB-CBs–HDPE. These results suggested that the EB irradiation enabled a specific volume expansion behavior via enhanced crosslinking among CBs, polar additives, and HDPE, inhibiting the formation of conductive networks in the nanocomposites. Thus, it can be concluded that polar additives and further EB irradiation played an important role in enhancing the PTC performances. We believe the findings provide crucial insight for designing carbon–polymer nanocomposites with PTC behaviors in various self-regulating heating devices.

Investigation of Cyclic Stability and Pyro-Resistive Properties in High-Density Polyethylene/Tungsten Carbide Composites Under Thermal and Electric Activation

“…Common strategies involve the establishment of a synergistic network between fillers , or the introduction of a secondary phase polymer, both of which prove advantageous in enhancing PTC performance. Furthermore, modifications to conductive fillers, , the addition of auxiliaries, , and cross-linking treatments are viable strategies for adjusting the microstructure of composite materials, promoting the formation of stable conductive networks, and enhancing the PTC reproducibility of the composite materials. For filler selection, metal-conductive compounds, owing to their excellent resistance to oxidation and conductivity, are gradually replacing easily oxidizable metal powders and carbon black (CB) fillers with inferior processing capabilities.…”

Core–Sheath Fiber-Based Triboelectric Nanogenerators for Energy Harvesting and Self-Powered Straight-Arm Sit-Up Sensing

“…Wearable electronics and wireless communication network gain the rapid development, which is making a difference in the lifestyle of people. − The stretchable and flexible energy devices that provide energy for the mobile wearable devices and wireless communication network are more significative, gaining widespread attention. − The traditional batteries with disadvantages of large size, inadequate safety, unsatisfactory flexibility, and frequent recharging have not met the requirements of wearable electronics. , Thus, it is highly necessary to develop a smart, integrated, and flexible power supply. Triboelectric nanogenerators (TENGs), based on the coupling of triboelectrification and electrostatic induction, can effectively scavenge the manifold high-entropy mechanical energy and generate electrical energy. − Furthermore, the one-dimensional fiber-based TENGs (F-TENGs) arise rapidly to break through the limitations of the traditional airtight film-based TENGs for the wearable applications. ,− The F-TENG possesses the characteristics of good breathability, comfort, and flexibility, which make it more suitable to wear. , Accompanied by human body motion, F-TENGs can successfully harvest biomechanical energy.…”

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

“…[1][2][3][4][5][6][7][8][9][10] This pyroresistive property has fascinating applications in the field of electrical industry, such as self-regulating heater, the over current protective device, and high sensitive temperature sensors, etc. [11][12][13][14][15][16][17][18][19][20][21] Meanwhile, the crystalline polymer matrix also has a variety of selectivity during the melting temperature (T m ) ranging from 20 to 300 C to perfectly meet the requirements of temperature sensitive characteristics in specific temperature ranges. 6 In order to realize satisfactory room temperature resistivity and pyroresistive property, a suitable concentration of conductive fillers is needed to be introduced into the crystalline polymer matrix.…”

“…Polymer‐based positive temperature coefficient materials (PTCs) are a typical conductive polymer composites (CPCs) that present a tremendous increase in resistivity followed by the melting of the crystalline polymer matrix 1–10 . This pyroresistive property has fascinating applications in the field of electrical industry, such as self‐regulating heater, the over current protective device, and high sensitive temperature sensors, etc 11–21 . Meanwhile, the crystalline polymer matrix also has a variety of selectivity during the melting temperature ( T m ) ranging from 20 to 300°C to perfectly meet the requirements of temperature sensitive characteristics in specific temperature ranges 6 .…”