New hyper-crosslinked polymers for enhanced CO2 adsorption: Synthesis and characterization

Abstract

In this study, new hyper-crosslinked polymers (HCPs) were synthesized with 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) and p-naphtholbenzeine (NB) with different ratios of 4,4′-bis(chloromethyl)-1,1′-biphenyl (BCMBP) through the Fridel-Crafts (FC) method. The polymers were thoroughly characterized by Fourier-transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) surface area analysis, thermogravimetric analysis (TGA), and x-ray diffraction (XRD) confirming the successful synthesis of HCP-PTCDAs and hyper crosslinked p-naphtholbenzein polymers (HCP-NBs). BET analysis revealed that the maximum surface areas of HCP-PTCDA and HCP-NB were 962 m2 g−1 and 665.4 m2 g−1, respectively. The maximum pore volumes of HCP-PTCDA and HCP-NB were 1.26 cm3 g−1 and 1.90 cm3 g−1, respectively. The enhanced surface area and pore volume of HCP-PTCDAs were attributed to the lack of conformational changes in PTCDA during synthesis. The maximum CO2 adsorption capacities of the two polymers were obtained with HCP-PTCDA/20 and HCP-NB/5 (at 273 K and 1 bar: 2.75 mmol g−1 and 3.28 mmol g−1, respectively). Although the surface area of HCP-NB/5 was three times lower than HCP-PTCDA/20, it showed higher CO2 adsorption performance. Accordingly, these results revealed that pore volume and size distribution were one of the most determining parameters in CO2 adsorption. Compared with the literature, the improved CO2 adsorption performance, especially that of HCP-NB/5, showed that these polymers had relatively high potential.