STRUCTURE-PROPERTY RELATIONSHIPS OF POLYIMIDES - A MOLECULAR SIMULATION APPROACH

Chain flexibility and mechanical properties of four polyimides with di fferent chemical structures are simulated by molecular dynamics and mo lecular mechanics techniques to establish some structure-property rela tionships. The oxygen linkage in the diamine moiety of a polyimide giv es the highest flexibility whereas the sulfonyl linkage imparts the lo west flexibility to the polymer chain. A more flexible polyimide has s maller characteristic ratio, lower solubility parameter, lower elastic modulus, and larger yield strain. These simulated values show good ag reement with experimental data. (C) 1998 Elsevier Science Ltd. All rig hts reserved.