TriSilanolPhenyl POSS-polyimide nanocomposites: Structure-properties relationship

Polyhedral Oligomeric Silsesquioxane (POSS)-polyimide (PI) thin films were synthesized from pre-mixed solution of oxydianiline-pyromellitic dianhydryde (ODA-PMDA) and TrisilanolPhenyl (TSP) POSS. POSS-PI polymerization reaction kinetics was studied using Fourier Transform Infrared (FTIR) spectroscopy. The POSS-PI films were then investigated by tensile tests, followed by surface morphology examination using Atomic Force Microscopy (AFM) and Environmental Scanning Electron Microscopy (ESEM). An interdisciplinary approach was applied for establishing a relation between POSS-PI composites chemical microstructure properties and failure mechanisms. Inter molecular POSS-POSS interaction by either phase separation, or chemical POSS-POSS condensation reaction were observed as key factors, affecting the nanocomposite mechanical properties via formation of aggregates. The amount and density of these aggregates were shown to be composition dependent. A model based on formation and coalescence of voids during tensile tests was suggested for understanding the effect of the POSS content on the POSS-PI mechanical response. (C) 2009 Elsevier Ltd. All rights reserved.