Non-graphitizing carbon films were prepared from polycarbodiimide (PCDI) by applying stretching stresses at various stages of heat-treatment. It was intended to elucidate what stage of the heat-treatment is the most sensitive to the applied stress in regard to the development of the oriented texture. The preferred orientation induced in the stabilized films was not transferred to that of the carbonized films. The preferred orientation of the carbonized films was most effectively induced when a larger elongation was imposed on the films in the temperature region 400-480°C, where the nuclei of the carbon layer stacks were produced. Once a certain degree of preferred orientation was developed at the earliest stage of carbonization, it enhanced spontaneously during later stages of carbonization.
Yamashita, J., Shioya, M., Hashimoto, T., & Takaku, A. (1999). Preferred orientation induced in polycarbodiimide-based carbon films by stretching. Carbon, 37(4), 625–630. https://doi.org/10.1016/S0008-6223(98)00234-6