Thermal Analysis Of Representative Additives In Heated Cigarette

Heat-not-burn cigarettes are one of the most promising and dynamic of the new tobacco products.Compared to traditional cigarettes,heat-not-burn cigarettes are missing a large number of aroma components that can only be obtained through high temperature pyrolyzing,so additional additives are needed to enrich the smoke.The current research on heat-not-burn cigarette additives is in its infancy,lacking basic thermal data,and its use is almost always based on traditional cigarettes,however,due to differences in dosage and use temperature,the original traditional cigarette additives are not fully applicable to heat-not-burn cigarette.The purpose of this thesis is to study the pyrolysis mechanism,pyrolytic product distribution and practical application effects of several representative additives under heated state in heat-not-burn cigarette.The main study contents and results are as follows.(1)Under two simulated thermal pyrolysis conditions of heat and burn,pyrolysisgas chromatography/mass spectrometry(Py-GC/MS)was used to compare the types of decomposition products and the relative contents of decomposition products of WS series cooling agent.The results revealed that the main factors influencing the pyrolyzing results of the additives were the pyrolyzing atmosphere,pyrolyzing temperature,and the structure of the additives.The selected cool agents all had a transfer rate of 99% or more under heating conditions,retaining the original coolness and meeting the requirements for the use of heat-not-burn cigarette additives.Among them,WS-5 requires less energy for pyrolysis as well as lower requirements for smoking equipment,and has the best applicability.(2)Py-GC/MS,thermogravimetry analysis(TGA)and Coats-Redfern kinetic fitting method were used to investigate the effects of the heating rate,the presence of nicotine salts and the type of organic acids on the thermal properties of nicotine salts.The results showed that the pyrolysis of nicotine salts in the heated state was a nonspontaneous heat absorption process,and the main decomposition products were nicotine,anhydrides,carboxylic acids and N-heterocyclic compounds.With the increase of the heating rate,the thermal properties curve showed a hysteresis phenomenon,and the pyrolysis interval shifted to the high temperature end.(3)The essential oils of three natural plants containing rose aroma were extracted by water vapor distillation,and after pyrolysis under heated condition,the decomposition components were analyzed by heatmap and principal components analysis(PCA),and further combined with heat-not-burn cigarette sensory tasting to compare the heat release regularity of their key aromas.The results showed that there were differences in the pyrolysis products of different essential oils,but the key aroma components were the same,and rose essential oil,rose wood essential oil and rose hips essential oil all improved the suction quality of heat-not-burn cigarette.(4)Determination of the thermal decomposition products of ester additives under heating conditions by Py-GC/MS and deduction of the pyrolysis mechanism on the basis of the decomposition products,the ester additive of 0.05%(mass fraction)is added to the heat-not-burn cigarette and then the smoke aerosol was trapped by smoking machine.The results showed that under heating conditions,the esters first underwent hydrolysis to form the corresponding alcohols,and then were converted to unsaturated hydrocarbons by oxidative dehydrogenation.Among them,the ester additive is affected by its own boiling point,the cigarette core retention ranges from 15.4% to 37.04%.(5)Heat-not-burn cigarette samples made with different smoke generator proportion were used to study the effects of smoke generator proportion on the heat transfer properties of tobacco by differential scanning calorimetry(DSC)and transient laser flash method,and the effects of smoke generator proportion on the mass transfer properties of tobacco by TGA method and smoke aerosol trapping method.The results showed that the addition of propylene glycol could both enhance the heat transfer effect of the tobacco and promote the release of key components within the tobacco.Compared with the compounded smoke generator,the single-component smoke generator had better moistening retention performance and greater aerosol particle number concentration but smaller particle size.On the whole,the best heat and mass transfer performance of the tobacco was achieved when glycerol: propylene glycol(mass fraction)= 8:2.