Deodorizing mechanism of adhesive foam sheet containing cellulose nanofibers against hydrogen sulfide gas

An aqueous dispersion of TEMPO-oxidized cellulose nanofibers with copper carboxylate groups (TOCN-Cu) (TEMPO: 2,2,6,6-tetramethylpiperidine-1-oxyl radical) and a rubber latex were mixed. This mixture was then coated onto an opaque polypropylene (PP) or transparent poly(ethylene terephthalate) (PET) film and thermally dried to prepare a TOCN-Cu-containing foam rubber layer on the PP or PET film. The foam rubber side of each sheet was adhered to a glass plate using pressure, which was then placed in a test bag. The adsorption of odorous H 2 S on each glass plate/TOCN-Cu-containing foam rubber/film was evaluated by determining the H 2 S gas concentration in the test bag against the treatment time, which had a length of up to 317 days. The H 2 S gas penetrated from the edge of each composite sheet and reached the interior, forming CuS, which was homogeneously distributed throughout the foam rubber layer through its continuously connected pore. The TOCN-Cu was primarily present near the rubber/air interface in the foam layer of the composite adhesive sheet, resulting in excellent deodorizing functions. However, H 2 S gas was mostly adsorbed to the TOCN-Cu-containing foam rubber sheets by physical interactions. This is because the S/Cu molar ratio for a representative H 2 S-adsorbed sheet was calculated to be ~2800. • TOCN-Cu-containing foam rubber sheets were prepared by coating on a film and drying. • TOCN-Cu aggregates are primarily present at the rubber/air interfaces in the sheets. • The foam sheets can be used as printable and adhesive/detachable poster sheets. • Furthermore, the foam sheets exhibit excellent deodorizing behavior against H 2 S gas.