Silicone Elastomers with Exceptional Elongation

Polysiloxanes elastomers formed by the step-growth of heterobifunctional macromers achieve high molecular weights and show elastomeric behavior.  Advanced NMR and DSC techniques as well as rheological studies indicate the absence of crosslinking,  When formed into nanocomposites by the incorporation of surface passivated fumed silica, they exhibit elongations approaching 5000%. At extensions comparable to conventional silicone elastomers, they show similar elastic recovery.  At greater extensions, recover is reduced marginally.  These materials are readily manufacturable and can be compounded and processed similar to conventional two-component platinum cure silicone RTVs.  The synthesis, characterization, mechanical properties and computational modeling will be presented.