Carbon capture hybrid systems

Many radical cations derived from cyclopropane (or cyclobutane) systems undergo bond formation with nucleophiles, typically neutralizing the positive charge and generating addition products via free-radical intermediates [140, 147). In one sense, these reactions are akin to the well known nucleophilic capture of carbocations, which is the second step of nucleophilic substitution via an Sn 1 mechanism. The capture of cyclopropane radical cations has the special feature that an sp -hybridized carbon center serves as an (intramolecular) leaving group, which changes the reaction, in essence, to a second-order substitution. Whereas the SnI reaction involves two electrons and an empty p-orbital and the Sn2 reaction occurs with redistribution of four electrons, the related radical cation reaction involves three electrons. 

Hybrid composite sj tems that comprise mixtures of different filler types guarantee great versatility in capturing preferred electrical prop)erties combined with additional desired properties. For example, the electrical properties of carbon black/poljTner composites were enhanced significandy by the addition of just a small fraction of the more expensive CNTs. Similarly, numerical simulations by Rahatekar et rtf show that addition of spheres to a fiber system does not modify the percolation threshold of the fiber system significantly when the fraction of spheres is small, as the contribution of the fibers in the overall network fonnation is dominant. These studies suggest that hybrid composites can combine rodlike fillers to control the electrical properties and spherical fillers to modulate the mechanical, thermal, or optical properties. The possibilities are even further extended by the opportunities presented by combining disaete nanopartides with continuous fiber composites. 

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