Ammoxidation of polyethylene: A new route to carbon

Carbon fibers boast excellent mechanical properties, but widespread adoption into everyday composite materials is limited by their high cost. Polyethylene seems like an ideal low-cost precursor based on its high carbon content, low cost, and melt-processability, but as a saturated hydrocarbon it is functionally far removed from the graphitic structure. Here, we report that after crosslinking, the oxidation of polyethylene can be performed in a controlled manner to provide significant yields of oxidized black solid that resembles its original shape and can be subsequently heated under inert atmosphere to yield a carbonaceous solid in 10–30% carbon yield. When oxidation is conducted in the presence of ammonia, nascent carboxylic acids en route to CO2 evolution are intercepted to provide up to 70% carbon yield. This ammoxidation process was characterized by solid-state nuclear magnetic resonance, infrared spectroscopy, elemental analysis, and X-ray photoelectron spectroscopy to contain various nitrogen containing functional groups, including amides, lactams, imides, and pyridines. The resulting carbonaceous structures were characterized by Raman spectroscopy, elemental analysis, high resolution transmission electron microscope and selected area electron diffraction to be consistent with a highly disordered wavy lattice carbon structure.