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Highly conducting carbon nanotubes (CNTs)/polydimethylsiloxane (PDMS) composite with a low concentration (5.7 vol.%) has been shown to be applicable in a highly controllable electric heating element. Due to a high shear-processing technique for mixing CNTs into an uncured PDMS matrix, the CNT/PDMS composites have a fairly uniform dispersion and no agglomeration of CNTs. The percolation threshold of the prepared CNT/PDMS composite is achieved \sim0.03~vol.\%, which is one of the lowest values previously reported in the literature. The fabricated CNT/PDMS composites can be quickly heated from room temperature to 200^\circC within 30 s by applying a DC voltage of 12 V. In addition, the CNT/PDMS composite show good thermal stability and repeatability during a long-term heating test. Our proposed CNT/PDMS composites could be used as a basis for light-weight and flexible heating-unit applications. [ABSTRACT FROM AUTHOR]

Carbon nanotube (CNT) composites are ideal materials for electric heating (E-heating) components owing to their lightweight, rapid heating ability, and easy processability for microscale patterns. However, careful consideration of their thermal stability and the effect of E-heating on CNT composites is necessary to ensure safety and long-term durability. Thermal degradation of CNT composites as a result of E-heating was found to be much more severe than air convection heating (C-heating). Enhanced mechanical properties of CNT composite were observed after 40 h C-heating, while E-heating composites became fragile that the matrix was severely damaged at the same temperature/hours. Consequently, the electrical resistance of the CNT composite for E-heating was dramatically increased. To avoid thermal degradation and a dramatic increase in resistance, the E-heating temperature should be much lower than the temperature limit of thermally stable polymer. In addition, thermal degradation of the polymer matrix could be relieved through the addition of CNTs, which can be understood as parallel resistor model, by spreading thermal concentration throughout the polymer matrix. [ABSTRACT FROM AUTHOR]