Abstract
We report on the pyrolysis mechanism of aromatic polyimide (PMDA-ODA) and the obtained carbon precursor structure,and discuss the effect of the structure on the graphitization reaction. The reaction for the generation of the carbon precursorand its structure were examined, in consideration of the molecular orientation in the PMDA-ODA film, the detailed sizechange, weight loss, total carbon yield, and analysis of evolved gas during the pyrolysis reaction. The pyrolysis starts with theevolution of CO and CO2 gas by partial polyimide ring opening, and the reaction intermediates unite mutually before thepolymer chain completely disintegrates. The reaction uniting the polymer chains at the initial stage of the pyrolysis reactioncan explain why the molecular orientation of the polymer is maintained in the carbon precursor. The orientation in the carbonprecursor is partly retained in the carbonization process, resulting in easy graphitization at higher temperatures.
