How does temperature effect the conductivity of polyester polymers?5 answersTemperature has a significant impact on the conductivity of polyester polymers. Studies on various polymer blends and composites reveal that an increase in temperature generally leads to enhanced conductivity. This phenomenon is often attributed to the rise in free ion mobility due to thermal energy, allowing for easier movement of charge carriers within the material. The conductivity-temperature relationship typically follows an Arrhenius-type thermally activated process, where conductivity shows a linear increase with temperature. Additionally, the activation energy required for conductivity decreases with an increase in the blend composition or filler content, indicating a more efficient charge carrier movement at elevated temperatures. Overall, temperature plays a crucial role in modulating the electrical properties of polyester polymers, influencing their conductivity behavior significantly.
How to measure the conductivity of powder samples?5 answersTo measure the conductivity of powder samples, various methods and devices have been developed. One approach involves using a powder conductivity test device that includes a thermostat, a powder test clamp, and a conductivity tester, ensuring a stable test environment and improving result accuracy. Another method utilizes a powder conductivity tester with components like a processor, display screen, resistance measuring device, and pressure sensor, allowing for simple and effective testing that can be easily carried out in the field. Additionally, a theoretical analysis of eddy current sensor interactions with powder particles can help calculate particle conductivity based on measured values, considering factors like powder density, frequency of the probing field, and electrical conductivity of particles. These methods and devices offer precise and efficient ways to determine the conductivity of powder samples.
How does temperature affect electrical conductivity of polymers?5 answersTemperature has a significant effect on the electrical conductivity of polymers. In some cases, an increase in temperature leads to an increase in conductivity. For example, the conductivity of PVA-Chloral Hydrate blends increases with increasing temperature up to 353 K. On the other hand, at sufficiently high temperatures, the current-voltage characteristics of Poly(diphenylene phthalide) (PDP) thin films are described by the injection model of currents limited by space charge. Additionally, the conductivity of insulating diblock copolymer systems filled with conductive fillers changes in response to temperature-induced changes in morphology. Furthermore, the thermal and electrical conductivities of conductive polymeric composites (CPCs) can have either a linear or nonlinear increasing behavior with increased temperatures, depending on the conduction mechanism. The conductivity of polymer electrolytes composed of PEO and sodium iodide also shows a linear variation with temperature, suggesting an Arrhenius-type thermally activated process.
What are the factors that affect the electrical conductivity of a material?5 answersThe factors that affect the electrical conductivity of a material include its structural state, chemical composition, content of alloying elements, presence of different types of phases, dislocation substructure, defect concentration, and defect mobility. In addition, external factors such as temperature, pressure, electrical field, moisture, and even smell can also influence the electrical conductivity of specific materials. For crystalline solids, the energy-band characteristics of the substance play a significant role in determining their electrical conductivity. Furthermore, in polymer-based composites reinforced with iron particles, factors such as temperature, current density, external applied load, and applied magnetic field can affect the electrical conductivity. Understanding these factors is crucial for improving the properties and performance of materials used in various applications.
How is the electrical conductivity of conductive composite measurent?5 answersThe electrical conductivity of conductive composites is measured using various techniques. Impedance spectroscopy is commonly used to measure the electrical conductivity of polymer composites based on solid solutions. In this method, the frequency dependence of the total electrical conductivity is obtained by measuring the impedance of the composite in a specific frequency range. Nyquist plots are constructed and analyzed to study the effect of cationic substitution on the electrical conductivity. Another method involves using a 4-in-line-probe dc electrical conductivity-measuring instrument to determine the electrical conductivity of composites. This method measures the electrical conductivity of compressed pellets of the composite material. The electrical conductivity is typically measured in the range of 10-4 to 10-2 S cm-1 and follows the Arrhenius equation. Overall, these measurement techniques provide valuable insights into the electrical conductivity of conductive composites.
What is the difference between redox polymers and conductive polymers?3 answersRedox polymers and conductive polymers are both types of polymers with electrochemical activity. However, there are some differences between them. Redox polymers are characterized by their mechanical flexibility, molecular diversity, and low cost, making them promising candidates for supercapacitor applications. They have diverse molecular structures and redox centers, which allow for efficient energy harvesting and storage. On the other hand, conductive polymers combine the mechanical properties of organic polymers with charge transport, opto-electronic, and redox properties. They can be easily tuned to have properties similar to semiconductors and metals. Conductive polymers have been widely used in opto-electronic devices, energy-conversion and storage systems, sensors, actuators, and biomedical applications. In summary, while both redox polymers and conductive polymers have electrochemical activity, redox polymers are specifically designed for supercapacitor applications, while conductive polymers have a broader range of applications.