Regenerated cellulose/multiwalled carbon nanotube composite films with efficient electric heating performance

We have manufactured regenerated cellulose-based composite films reinforced with pristine multiwalled carbon nanotube (MWCNT) by a facile casting of cellulose/DMAc/LiCl solutions containing 0.2-10.0 wt% MWCNT and have investigated their application as electric heating materials by examining microstructure, thermal stability, and electrical properties. TEM images showed that the pristine MWCNT was dispersed well in the regenerated cellulose matrix. The composite films were found to be stable thermally up to ∼275 °C. The electrical resistivity of the regenerated cellulose/MWCNT composite films decreased significantly from ∼109 Ω cm to ∼101 Ω cm with increasing the MWCNT loading, particularly at a certain MWCNT content between 2.0 and 3.0 wt%. Accordingly, the composite films with 5.0-10.0 wt% MWCNT contents, which possessed low electrical resistivity of ∼102-101 Ω cm, exhibited excellent electric heating performance in aspects of temperature responsiveness, steady-state maximum temperature, and electrical energy efficiency at constant applied voltages. For instance, the composite film with 10.0 wt% MWCNT had well-controlled steady-state maximum temperatures of 40-189 °C at 20-80 V, characteristic temperature growth constant of ∼1 s, and electric power efficiency of ∼5.4 mW/°C, which performance remained unchanged under repeated experiments for several hours.