Methodology for Assessment of Morphological and Thermal Characteristics of Nanographene Platelets

Abstract

This paper describes the methodology used to characterize the as-received nanographene platelets (NGPs) from several nanomaterial manufacturers. The microstructures of these NGPs were first examined using scanning electron microscopy at several different magnifications. The thermal stability of these NGPs was evaluated using thermogravimetric analysis with at least three different heating rates, such as 5, 10, 20, and 40 o C/min in argon or nitrogen atmosphere. The residual mass and rate of mass loss of these NGPs was compared. The kinetics parameters, such as the activation energy and pre-exponential factor of these NGPs were then calculated using the isoconversion technique. Eleven NGPs were characterized using the above methods. The similarities and differences of these NPGs were compared. Based on these facile techniques, one can rank the morphological and thermal characteristics of these NGPs. The methodology serves as a unique screening technique to select the appropriate NPG that can be chosen for whatever specific application is desired. NomenclatureA = Pre-exponential factor A avg = Average pre-exponential factor A s = Maximum mass loss attainable Cpm = o C/min E = Activation energy E avg = Average activation energy E peak = Peak activation energy 1 Sr. 2 k = Kinetic constant n = Order of reaction R = Universal gas constant T = Temperature t = Time w = Instantaneous weight X s = Solid conversion β = Heating rate Subscripts avg = Average f = Final o = Initial peak = Peak