Enhanced thermal response and regulated release behavior of reconstituted tobacco via a graphene/TOCNF thermally conductive network

The thermophysical properties and pyrolysis behavior of reconstituted tobacco (RT) are closely associated with aerosol release in heated tobacco products (HTPs). However, the inherently low thermal conductivity of RT restricts heat transfer and temperature uniformity, thereby limiting the efficient release of key aerosol constituents (KACs). Herein, continuous heat-transfer networks were built into the cellulose fiber matrix via graphene-derived thermal pathways. TEMPO-oxidized cellulose nanofibrils (TOCNF), rich in carboxylate groups, were used to stabilize graphene and suppress nanosheet restacking, forming a homogeneous G/TOCNF gel. During wet pulping, cationic guar gum (CGG) served as a positively charged bridge to mediate electrostatic adsorption between the negatively charged G/TOCNF complex and cellulose fibers, enabling uniform graphene retention and stable immobilization. This interfacial regulation produced a thermally conductive substrate (TCS) with a continuous three-dimensional graphene thermal pathway. RT-5 with 5.03 wt% graphene achieved a thermal conductivity of 0.3168 W/m·K, a 52% increase over RT-0. Owing to enhanced thermal transport, the KACs release rate increased from 57.52% to 63.13%. TG/DTG analysis revealed graphene-mediated thermal regulation and composition-dependent mass-loss redistribution, reflected by shifted decomposition peaks and a reduced high-temperature mass-loss rate from −0.426% to −0.342%/℃. Kinetic analysis showed that the mean activation energy increased from 199.44 to 376.54 kJ/mol and from 203.38 to 388.92 kJ/mol by the FWO and KAS methods, respectively, indicating elevated pyrolysis barriers and regulated decomposition kinetics. Overall, the G/TOCNF-CGG system improves thermal management, KAC release, and pyrolysis regulation for next-generation HTP functional base materials.