Functionalized polyhedral oligosilsesquioxane (POSS) macromers: New graftable POSS hydride, POSS alpha-olefin, POSS epoxy, and POSS chlorosilane macromers and POSS-siloxane triblocks

A series of polyhedral oligomeric silsesquioxanes (POSS) monomers bearing s ilane or alpha-olefin substituents have been prepared and their chemistry e xplored. Both the POSS silanes and alpha-olefin monomers readily participat e in hydrosilation chemistry and have been used as starting materials for t he preparation of POSS sol-gel-type reagents. Similarly, POSS silanes and a lpha-olefins are reactive towards silane- and olefin-functionalized polymer s, which makes them useful as grafting reagents. The utility of these reage nts as graftable monomers was demonstrated by synthesis of a series of POSS -siloxane-POSS triblock polymers. Thermal and X-ray diffraction (XRD) chara cterization of the triblock polymers was performed in order to examine how the length of the siloxane segment affects the properties of the polymer. T he POSS alpha-olefin monomers were found to be unreactive with respect to Z iegler-Natta polymerization, The reaction of POSS Lu-olefins with m-chlorop erbenzoic acid (MCPBA) to give POSS epoxides was demonstrated and the therm al stability of the POSS epoxides determined. Copyright (C) 1999 John Wiley & Sons, Ltd.