Completely discontinuous organic/inorganic hybrid nanocomposites by self-curing of nanobuilding blocks constructed from reactions of [HMe2SiOSiO1.5]8 with vinylcyclohexene

摘要

The reaction of 4-vinyl-1-cylcohexene with [HMe2SiOSiO1.5]8 provides tetra- and octa-2-cyclohexenylethyloctasilsesquioxanes.The tetrabifunctional [cyclohexenylethylMe2SiOSiO1.5]4-[HMe2SiOSiO1.5]4 (average degree of functionalization) melts near 80 °C and can be cast and then cured (by thermal hydrosilylation) into transparent nanocomposite shapes.These materials,while not nanoporous,offer dielectric constants of 2.8-2.9 at 100kHz to 3 MHz,and are air stable to temperatures >400°C.The resulting materials appear (by X-ray diffraction) to be partially ordered after curing.The octafunctional material also melts at low temperatures (ca 120 °C) and can be copolymerized with hydridosiloxanes to give similar materials with lower thermal stability.The synthesis and characterization of the starting materials is described,as well as thermal curing studies and properties characterization of the resultant nanocomposites.