Cellulose nanofiber/polyimide composites for highly-efficient air filters

Cellulose nanofiber (CNF) nanopapers from garlic skin prepared by vacuum filtration were soaked in various concentrations of polyimide (PI) solution (0-15% w/v). The samples were dried in a vacuum oven and pressed in a hot pressing machine at 120 degrees C for 1 h to obtain CNF/PI composite nanopapers. Even though the composites showed lower Young's modulus and tensile strength, their toughness and elongation were much higher than those of the CNF nanopapers. Moreover, the impregnation of nanopapers in PI solution caused the formation of smaller pores and limited the pore size distribution but increased the BET-specific surface area of the samples, which led to a superior filtration capacity and a high quality factor (QF). The composites prepared by impregnation with 5% wt PI showed the most promising composite to be developed as air filters, as these composites had flexibility and showed superior filtration (99%) efficiency and higher QF than the commercial filters.

Automated summary

Cellulose nanofiber (CNF) nanopapers from garlic skin were impregnated in various concentrations of polyimide (PI) solution. The resulting CNF/PI composite nanopapers showed lower Young's modulus and tensile strength, but higher toughness and elongation compared to the original CNF nanopapers. The impregnation of nanopapers in PI solution not only led to the formation of smaller pores and limited pore size distribution, but also increased the BET-specific surface area, resulting in superior filtration capacity and a higher quality factor (QF). Composite materials prepared by impregnation with 5% wt PI showed the most promising potential to be developed as air filters, with flexibility, superior filtration efficiency (99%), and a higher QF than commercial filters.