Graphene oxide enhances thermal stability and microwave absorption/regeneration of a porous polymer

Microwave regeneration of adsorbents offers several advantages over conventional regeneration methods; however, its application for microwave transparent adsorbents such as polymers is challenging. In this study, hypercrosslinked polymer/graphene oxide (GO) nanocomposites with large surface area and enhanced micro-wave absorption ability were synthesized. Polymers of 4, 4'-bis ((chloromethyl)-1, 1'-biphenyl-benzyl chloride) were hypercrosslinked through the Friedel-Crafts reactions. GO sheets were synthesized through the Hummer's method. Nanocomposites with different GO contents (1-8 wt%) were synthesized by solution mixing method. Thermogravimetry analysis revealed a large enhancement in the thermal stability of GO-filled nanocomposites compared to pristine polymer. N2 adsorption isotherm analysis showed 7% and 10% reduction in BET surface area and total pore volume of the nanocomposite with 8 wt% GO. Compared to the pristine polymer, the dielectric constant and dielectric loss factor increased from 5 to 17 and 0.05-1.6, respectively, for the nano-composites with 8 wt% GO. Microwave-assisted desorption of toluene from samples revealed more than 160 oC and 4 times improvement in the desorption temperature and desorption efficiency, respectively, by addition of 4 wt% GO to the polymer. This study showed the important role of GO addition for efficient microwave-assisted regeneration of polymer adsorbents.

Automated summary

This study demonstrates the important role of graphene oxide (GO) addition in achieving efficient microwave-assisted regeneration of polymer adsorbents, by synthesizing hypercrosslinked polymer/GO nanocomposites with large surface area and enhanced microwave absorption ability.