High Pressure Synthesis of 1D Polymer/Zeolite Nanocomposites

Recently, simple carbon based polymers have been synthesized at high pressures in silicalite, a pure SiO2 zeolite with a 3D system of mutually interconnected microchannels. These protocols permitted otherwise unstable polymers to be stabilized and protected from the atmosphere and to obtain an entirely novel class of nanocomposites with modified physical properties. In these 3-D systems, channel interconnection may prevent ideal, isolated polymer chains to be obtained. In this work, the high pressure (5-10 GPa) synthesis of two archetypal, linear polymers polyacetylene (PA) and polycarbonyl (pCO) in the 1D channel system of the pure SiO2 zeolite ZSM-22 (TON) has been performed. The two resulting nanocomposites PA/TON and pCO/TON are organic/inorganic composite materials, which are good candidates as highly directional semiconductors and high energy density materials, respectively. The synthesis was performed in diamond anvil cells, starting from dense C2H2 and CO, confined in ZSM-22, and the nanocomposites were recovered at ambient conditions. The monomer polymerization was proven by IR spectroscopy and synchrotron X-ray diffraction measurements. DFT calculations were performed in order to obtain insight about the configurations of the 1D embedded polymers.