Residual stress and microstructures of aromatic polyimide with different imidization processes

Processing of polyimide (PI) from precursor polyamic acid (PAA) solution in volves simultaneous imidization, evaporation of solvent and crystallization , so imidization process influences the final properties of PI. The residua l stress at the interface between the most popular PI (PMDA-ODA) and the al uminum substrate was measured by X-ray diffraction method and the relations hip between the microstructure and the mechanical properties was investigat ed for PI with different imidization processes. The residual stress and the mechanical properties of PI depend on the imidization process. The skeleta l structure is suggested to be changed by the amount of residual solvent du ring imidization process, which brings the difference in the residual stres s. (C) 2000 Elsevier Science Ltd. All rights reserved.