Azodicarbamide (ADCA) was added to carbon nanotube (CNT) paste to protect it from degradation. This agent produces nitrogen gas (N(2)) by heating at 190-210 degrees C, which acts as the anti-oxidant for carbon nanotube paste. The measurements of field emission and lifetime were evaluated in a vacuum chamber with a diode structure with pulsed current (duty of 1/500) mode; the lifetime of protected carbon nanotube samples was about five times greater than that of the pristine ones. (C) 2007 Elsevier Ltd. All rights reserved.