Novel functional nitrile butadiene rubber/magnetite nano composites for NTCR thermistors application

Abstract

A new negative temperature coefficient of resistor (NTCR) thermistors based on nitrile butadiene rubber/magnetite (NBR/Fe 3 O 4 ) nanocomposites were successfully fabricated by conventional roll milling technique. X-ray diffraction and transmission (TEM) analysis showed that the product is mainly magnetite nanoparticles with diameter of 10-13 nm. The microstructure of (NBR/Fe 3 O 4 ) nanocomposites were examined by scanning electron microscopy (SEM) and FTIR spectroscopy. The dispersion of magnetite nanoparticles in the NBR rubber matrix and interfacial bonding between them were rather good. The thermal stability of nanocomposites was also obviously improved with the inclusion of the magnetite nanoparticles. The thermal conductivity, thermal diffusivity and specific heat of nanocomposites were investigated. The electrical conductivity of the NBR/Fe 3 O 4 increases with the rise in temperature exhibiting a typical negative temperature coefficient of resistance (NTCR) behavior like a semiconductor. The nature of the temperature variation of electrical conductivity and values of activation and hopping energy, suggest that the transport conduction process is controlled by hopping mechanism. Values of characteristics parameters of the thermistors like thermistor constant, thermistor sensitivity and thermistor stability is quite good for practical application as NTCR devices at high temperature.

Bio‐Inspired Multiple Cycle Healing and Damage Sensing in Elastomer–Magnet Nanocomposites

“…The presence of the MNPs did not affect the thermal stability of the NBR matrix, all samples started to degrade at same temperature. It was observed that the degradation of NBR started at 334 °C due to the decomposition of organic polymer molecules . Therefore, the prepared Magpols are suitable for any heat treatment up to temperature 334 °C without any thermal degradation.…”

“…It was observed that the degradation of NBR started at 334 °C due to the decomposition of organic polymer molecules. [30] Therefore, the prepared Magpols are suitable for any heat treatment up to temperature 334 °C without any thermal degradation.…”

Effect of magnetic and thermal properties of iron oxide nanoparticles (IONs) in nitrile butadiene rubber (NBR) latex

“…Similarly NBR/IONs composites were proven to withstand at higher temperature (Table 4) than NBR at 10, 30 and 50 % weight loss. It can be concluded that thermal stability of NBR/IONs composite was improved, contributed by high thermal stability of IONs to resist NBR chain mobility [20] . Temperature at 10 and 30 % weight loss of NBR/IONs 5 phr was higher compare to others NBR/IONs composites.…”

“…Specific enthalpy of T g was diminished from 1.43 J/g to 0.72 J/g when IONs loading was increased from 0 phr to 20 phr. This phenomenon was caused by phonon scattering reduction whereby IONs constrain the NBR segment mobility by entrapping phonons within IONs [20] . Figure 7 reveals that crystallization temperature of NBR and NBR/ONs composites were at 365 o C. Heating was induced orientation in amorphous state of NBR in order to align parallel to each polymer chain.…”

Novel electromagnetic interference shielding effectiveness in the microwave band of magnetic nitrile butadiene rubber/magnetite nanocomposites

“…As the microwave business grows and with the rapid development of electronic and communications technology, electromagnetic radiation has emerged as a new form of contamination in modern communities and has been listed as the third biggest pollutant 1. Recently, several electronic devices with high frequencies, including satellite communication, automobile collision prevention radar, accident surveillance of railroads, cellular phones, and wireless local area networks, have been developed and applied 2–6. The electromagnetic waves produced from some electronic devices have an adverse influence on the performance of other equipment and may cause malfunctions in medical equipment; industry robots cause harm to the human body and become a public nuisance 7–9.…”