Shun Zhou

Significant Removal of Harmful Compounds in Mainstream Cigarette Smoke Using Carbon Nanotubes Mixture Prepared by Catalytic Pyrolysis

Carbon nanotubes mixture (CNTM), synthesized by the pyrolysis of polypropylene (PP)/organically modified montmorillonite (OMMT) nanocomposites catalyzed by Ni2O3, was used as a filter additive to remove harmful compounds in mainstream cigarette smoke. CNTM is mainly composed of carbon nanotubes (CNTs) with a little amount of amorphous carbon, Ni element and the thermal degradation residue of OMMT. The textural structure of CNTM has mesoporous and macroporous nanostructures. After introducing 15 mg of CNTM into cigarette filter, some of the most important harmful compounds including tar, nicotine, benzo[a]pyrene (B[a]P) and phenolic compounds were more efficiently adsorbed in comparison with using commercial activated carbon, which can be related to the relatively bigger pore volume and a geometric confinement of CNT in CNTM for some toxic compounds in cigarette smoke. In particular, CNTs have a strong chemisorption capacity for B[a]P or phenolic compounds due to the π–π interactions between benzene rings.

Silane modification and characterization of activated carbon

Activated carbons have been wildly used as adsorbents for various purpose. When used in a cigarette filter activated carbon can selectively remove a number of the vapor phase compounds to varying degrees of efficiency. To improve the wet-feeling of cigarette smoke with AC in the filter, a new method is developed to chemically functionalize a coal-based activated carbon (AC) based on silanization reaction. Silanization using 3-glycidoxypropyltrimethoxy silane was performed after the oxidized AC was reduced by lithium aluminum hydride.N2 and water adsorption, FTIR, and XPS were employed to characterize the changes in the surface morphology, chemistry and physical conditions at different processing stages. Water content analysis in cigarette mainstream smoke (MSS) showed a positive result in the application of modified AC.

Studies on the thermal properties of poly(1,4-butylene terephthalate)/microencapsulated ammonium polyphosphate composites

This work aims to explore the potential of microencapsulated ammonium polyphosphate (MAPP) in poly(1,4-butylene terephthalate) (PBT). PBT/MAPP composites were prepared via melt blending method. The study of their thermal behaviors and thermal stability showed that the addition of MAPP with silica gel shell (MAPP(Si)) improved the relative crystallinity and thermal stability of PBT composites, in comparison with untreated ammonium polyphosphate and MAPP with polyurethane shell. Possible mechanisms for PBT/MAPP(Si) composites were investigated by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy. The results indicated that several PBT molecules may be grafted onto the surface of MAPP(Si), which improves the relative crystallinity and thermal stability of PBT/MAPP(Si) composites.

Interactions of tobacco shred and other tobacco-based materials during co-pyrolysis and co-combustion

The interactions of tobacco shred with other tobacco-based materials, like expanded cut tobacco, cut reconstituted tobacco and expanded cut stem during co-pyrolysis and co-combustion, were investigated using thermogravimetric analyzer. The results illustrated that the interactions barely existed during the co-pyrolysis, but promoted the combustion during the co-combustion process of all binary mixtures. Oxidative decompositions of solid char for all binary mixtures were promoted by the interactions during the co-combustion process. The activation energy distributions, which were obtained by the Kissinger–Akahira–Sunose method from the TG data, well explained how the interactions influenced the combustion of the binary mixtures. For further understanding the effects of interactions on the combustion behaviors of the mixed materials, the release characteristics of heat, smoke, CO and CO2 were determined by the cone calorimeter tests. Results demonstrated that the interactions among the binary mixtures enhanced the HRR rates and THR values, but reduced the smoke production rates, the amounts of total smoke production and the CO/CO2 ratio. Thus, it could be concluded that the health harm of cigarette smoking can be reduced by blending these tobacco-based materials to some extent.

Influence of Ammonium Polyphosphate on Thermal Decomposition of Reconstituted Tobacco and CO Evolution

The thermal behaviors and burning characteristics of reconstituted tobacco (RT) are strongly related with evolved gaseous products. The effect of ammonium polyphosphate (APP) as an additive of RT on the pyrolysis behavior and CO evolution was studied, emphasizing the role of heating velocity in reducing CO delivery of the mainstream smoke by APP. Thermogravimetric analysis (TGA) was employed to investigate the influence of APP on RT thermal behavior. Slow and flash pyrolysis of RT were compared to discuss the role of heating rate in decreasing CO by APP. TGA results demonstrated that, in dependence on APP concentration, APP influenced exothermal amount and weight loss rate during RT thermal decomposition, promoted the formation of char and retarded the thermal decomposition of RT. In addition, APP had a considerable influence on the evolution of gaseous products during thermal decomposition of RT. Both CO delivery per cigarette and that per puff in the smoking process were significantly reduced in depende...