10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
Abstract View
Preparation of Nanospherical Mesoporous Carbon Nitride with High Surface Area using Aerosol Generated Mesoporous Silica and Its Application as a Photoinitiator for Aerosol-Photopolymerization
JALAL POOSTFOROOSHAN, Masoom Shaban, Alfred P. Weber, TU Clausthal
Abstract Number: 715 Working Group: Materials Synthesis
Abstract The work presented here describes a continuous aerosol-based process to produce submicron spherical polymer particles using nanospherical mesoporous carbon nitride (NMCN) as a photoinitiator. In this regard, spherical raspberry-like silica particle was initially synthesized by spray drying of nanocolloidal silica, using polyvinylpyrrolidone (PVP) as a template, within the average aerosol residence time of 6 s in the tube furnace reactor. After removal of the PVP by calcination, spherical mesoporous silica (SMS) nanoparticle was obtained. Then, NMCN with a high surface area and pore volume has been synthesized via a nanocasting approach by using SMS as a hard template through a simple polymerization reaction between ethylenediamine and carbon tetrachloride as precursors [1].
The textural properties and chemical compositions of the obtained materials were investigated by employing diverse characterization techniques such as scanning mobility particle sizer (SMPS), N2 adsorption-desorption isotherms, transmission electron microscopy (TEM), scanning electron microscopy (SEM), Raman, small-angle X-ray scattering (SAXS), X-ray photoelectron spectra (XPS), FT-IR, wide-angle X-ray diffraction (XRD), thermogravimetric analyzer (TGA), and CHN analyses. The results revealed that the NMCN has a high nitrogen content (16.8 wt%) with a high surface area of ~718 m2/g, a pore volume of 1.22 cm3/g and a pore size of 23 nm.
In addition to experimental characterization, the optical properties of NMCN were studied theoretically by three-dimensional finite difference time-domain (FDTD) method. Experimental and simulation results confirm that the introduction of desired mesoporosity in the carbon nitride not only increases the surface area for accommodating active sites, but also improves the light absorption and consequently increases the generation rate of electron-hole pairs inside the NMCN.
Finally, NMCN nanoparticles exhibit excellent performance in photopolymerization of butyl acrylate monomer in the continuous aerosol-based process, within the average aerosol residence time of 90 s in the photoreactor. In this one-pot synthesis, NMCN nanoparticles acting not only as photoinitiators, but at the same time as fillers and templates.
The presented aerosol-photopolymerization process operates at room temperature and avoids the need for solvent and surfactant. More importantly, with this method, we could overcome the problem of producing composites of carbon nitride with hydrophobic polymers. Furthermore, we simulated the condition of NMCN nanoparticles during illumination in the gas phase process which can freely rotate. The results demonstrated that the hole density is almost equally distributed in the whole part of the NMCN nanoparticles, leading to efficient light harvesting and more-homogeneous photoreaction.
[1] J. Poostforooshan, A. Badiei, M. Kolahdouz, and A. P. Weber, ACS Appl. Mater. Interfaces, 2016, 8, 21731–21741.