Phenylethynyl Silsesquioxanes: Monomer Synthesis, Characterization,Thermolysis and Thermal Properties

Polyhedral Oligomeric Silsesquioxanes (POSS) are inorganic/organic cages that are used as high-tech additives to enhance the thermal, mechanical and surface properties of many polymeric systems. A useful analogy is that a POSS is nano-sized particle of silica solubilzed with organic modifiers (RSiO1.5)n; the organic periphery determines how well the POSS can interact with any host polymer, while the siliceous core adds thermoxidative stability. Beginning in 1993 and continuing today, there has been extensive research in understanding how POSS incorporation into various materials affects polymer properties. Herein is reported a synthesis strategy to produce POSS-containing, thermosetting phenylethynyls to yield high temperature materials with extreme thermo-oxidative stability, low moisture uptake and good mechanical properties.