•CO yields of flue-cured tobacco under the low-temperature heating conditions were quantitatively evaluated using SSTF.•The effects of temperature, air velocity and elemental compositions on CO yields were studied, respectively.•Temperature slightly influenced CO yield of heated tobacco at a fixed air velocity.•CO yield, with reducing air velocity, first increased fast and then tended to remain unchanged at a fixed temperature.•K/S is a very important factor influencing CO yields of heated tobacco.In this paper, the quantitative evaluation of CO yields of flue-cured tobacco under the low-temperature heating conditions was investigated using a steady state tube furnace (SSTF) on the basis of controlled equivalence ratio method. Then the effect of temperature, ventilation condition and elemental compositions on the CO yields was studied, respectively. There was a strikingly low CO yield of heated tobacco under a fixed ventilation condition in comparison with flaming or even smouldering tobacco, and the temperature just slightly influenced the CO yield of flue-cured tobacco under the low-temperature heating states. At a fixed temperature of 450 °C, the CO yield, with reducing air velocity, first increased fast and then tended to remain unchanged. The correlation study indicates that there were no significant relationships between CO yields and the individual element except for the content of carbon and hydrogen, while the significant negative correlations of CO yields with the ratio of potassium to sulphur (K/S) at the 0.01 level appeared. Further random-Forest analysis revealed that K/S is another important factor influencing CO yields of fuel-cured tobacco under the externally heated pyrolysis conditions after hydrogen content.

This work aimed to study the influence of γ-irradiation on the mechanical and thermal properties of flame retardant EVA/LDPE/ATH blends. Flame retardant poly(ethylene vinyl acetate)/low-density polyethylene/aluminum hydroxide (EVA/LDPE/ATH) blends were prepared, with a LOI value of 40 % and UL-94 V0 rating. The influence of different γ-irradiation levels on flammability as well as mechanical, electrical, and thermal properties of EVA/LDPE/ATH blends was investigated. The flame resistance of EVA/LDPE/ATH blends was found to be slightly improved after γ-irradiation, and meanwhile the mechanical, electrical, and thermal properties were all enhanced due to the increase of cross-linking density. Moreover, thermogravimetric analysis/infrared spectra (TG-IR) were used to explore the thermal degradation process of the EVA/LDPE blends. TG-IR results indicated that the thermal degradation of EVA/LDPE/ATH blends was delayed after γ-irradiation, and the reduced pyrolysis products amounts were responsible for the improved fire resistance and thermal stability.

In this paper, first the MP-modified reconstituted tobacco sheet (RTS) was prepared by a paper-making process. Thermogravimetric analysis coupled to Fourier transform infrared spectrometer (TG-FTIR) had been used to investigate the influences of melamine phosphate (MP) on the thermal decomposition and the formation of evolved volatile products of RTS. TG-FTIR results illustrated that the incorporation of MP into RTS could retard the thermal decomposition of the major components of RTS and meanwhile lead to the formation of more thermally stable char. Moreover, the main gases released during the pyrolysis of RTS and MP-modified RTS were H2O, CO2, CO, NH3, carbonyl compounds, alcohols, phenols, alkanes, and alkenes. The presence of MP changed the formation of evolved volatile products of RTS obviously. The effects of MP on the combustion behavior of RTS were studied by micro-scale combustion calorimetry and cone calorimetry. Results demonstrated that the formation of combustible gases was mainly determined by the thermal decomposition stage occurred in the temperature range of 150–600 °C. The incorporation of MP into RTS influenced the release of fuel gases and the char formation in the process of the thermal decomposition of RTS, and eventually retarded the flammability and combustibility of RTS.

In this paper, the formation mechanism of pyrolysis gases released during the pyrolysis of pectin under the conditions that simulate cigarette smouldering was investigated by thermogravimetric analysis coupled to Fourier transform infrared spectrometer (TG–FTIR). Moreover, the combustion behavior of pyrolysis gases was studied by micro-scale combustion calorimetry (MCC). TG–FTIR results illustrated that the composition of the gaseous products was mainly composed of CO2, H2O, CO, methanol, methane and carbonyl compounds. MCC results demonstrated that the combustion of pectin was mainly determined by the prolysis gases formed in the temperature range of 200–300 °C. Flash pyrolysis experiment in combination with high performance liquid chromatography (FPy–HPLC) was used to study the pyrolytic formation of eight carbonyl compounds (i.e. formaldehyde, acetaldehyde, acetone, acrolein, propionaldehyde, crotonaldehyde, methyl ethyl ketone and butyraldehyde) during the pyrolysis of pectin under the pyrolysis conditions of cigarette puffing. Results demonstrated that pyrolysis temperature influenced the formation of acetaldehyde, acrolein, propionaldehyde and butyraldehyde greatly, while nitrogen flow affected the generation of formaldehyde, acetone, crotonaldehyde and methyl ethyl ketone deeply.