TEMPO-oxidized cellulose nanofibrils reinforce low-moisture tobacco granules through nanofibrillar networking and molecular immobilization

Abstract

Tobacco granules used as aerosol-generating substrates in heated tobacco products require sufficient mechanical integrity to withstand granulation, handling, screening, and filling, particularly under low-moisture conditions. Low-moisture tobacco granules are prone to weak cohesion because insufficient water limits the mobilization of native binders. Here, TEMPO-oxidized cellulose nanofibrils (TEMPO-CNFs) were incorporated at 1.26 and 2.08% (w/w) to improve their structural integrity. Texture and rheological measurements showed dose-dependent increases in springiness, cohesiveness, apparent viscosity, and storage modulus. Model polyol systems, Fourier transform infrared spectroscopy, and low-field nuclear magnetic resonance indicated that TEMPO-CNFs formed a viscoelastic fibrillar network and reduced the mobility of water, propylene glycol, and glycerol through combined hydrogen-bonding, confinement, and viscosity effects. Thermogravimetric-differential scanning calorimetry revealed essentially unchanged mass-loss stages, maximum mass-loss temperatures (318 to 319 °C), and residues at 400 °C. Thus, TEMPO-CNFs provide a renewable reinforcement strategy for polyol-rich tobacco granules without markedly altering their thermal mass-loss behavior.