A Novel Route for Polystyrene Grafted Single-Walled Carbon Nanotubes and their Characterization

Direct Intertube Cross-Linking of Carbon Nanotubes at Room Temperature

Carbon nanotubes (CNTs) have long been regarded as an efficient free radical scavenger because of the large-conjugation system in their electronic structures. Hence, despite abundant reports on CNT reacting with incoming free radical species, current research has not seen CNT itself displaying the chemical reactivity of free radicals. Here we show that reactive free radicals can in fact be generated on carbon nanotubes via reductive defluorination of highly fluorinated single-walled carbon nanotubes (FSWNTs). This finding not only enriches the current understanding of carbon nanotube chemical reactivity but also opens up new opportunities in CNT-based material design. For example, spacer-free direct intertube cross-linking of carbon nanotubes was previously achieved only under extremely high temperature and pressure or electron/ion beam irradiation. With the free radicals on defluorinated FSWNTs, the nanotubes containing multiple radicals on the sidewall can directly cross-link with each other under ambient temperature through intertube radical recombination. It is demonstrated that carbon nanotube fibers reinforced via direct cross-linking displays much improved mechanical properties.

Fabrication of high-k epoxy composites with low dielectric loss based on polymer shell-coated multiwalled carbon nanotubes

A core–shell microstructured hybrid was controllably synthesized by coating cross-linked polymer shells onto multiwalled carbon nanotubes (MWCNTs) via direct in situ free-radical polymerization and was compounded with epoxy to solve the problem of large dielectric loss.

Regulated dielectric loss of polymer composites from coating carbon nanotubes with a cross-linked silsesquioxane shell through free-radical polymerization

We report a synthetic strategy for coating multiwalled carbon nanotubes (MWCNTs) with cross-linked octa-methacrylate-polyhedral oligomeric silsesquioxane (MA-POSS) by direct, in situ free-radical polymerization in a controlled manner. This strategy resulted in a core-shell structure with an MWCNT center. The shell thickness could be varied from ∼ 7 nm to 40 nm by choosing different initiators, solvents, and weight ratios of MWCNT and octa-MA-POSS. Coated MWCNT hybrids had controlled electrical performance depending on the coating layer thickness and were well-dispersed in the polymer matrix. POSS-coated MWCNTs were compounded with poly(vinylidene fluoride) to obtain a composite with high dielectric permittivity and low dielectric loss.