Reconstituted Tobacco Sheet Research Articles

A FACILE METHOD TO PRODUCE HIGH-BULK AND HIGH-STRENGTH ROLLED RECONSTITUTED TOBACCO SHEET WITH REFINED TOBACCO CELLULOSE FIBERS

The rolling method is a pivotal means for reconstituted tobacco sheet (RTS) production due to its cost-effectiveness. However, the traditional rolling method is limited by its raw material grinding processes and yields of rolled RTS (RRTS) with subpar strength and bulk. Therefore, it is a challenge to develop a method to produce high-strength and high-bulk RRTS. Here, by replacing traditional raw materials grinding processes with papermaking refining processes, we present a facile and practical method to produce RRTS with elevated bulk and strength. This method separately refines tobacco leaves and stems into long and coarse leave and stem cellulose fibers. These fibers were subsequently reconstructed into RRTS. The detailed process parameters were optimized. The comparative RRTS with flax fibers instead of stem fibers was investigated. The optimal formula of new RRTS was determined. The updated processes, along with the use of refined cellulose fibers, led the RRTS to a significant improvement in strength and bulk, with a 5.3-fold increase in strength, and a 0.7-fold increase in bulk, while smoking qualities were preserved, which surpassed the smoking experience of RRTS with flax fibers. We anticipate this work will enhance the qualities of RTS and facilitate the transition of traditional tobacco industries toward healthier directions.

Recycling of tobacco waste: Development of reconstituted tobacco sheet with suitable strength and low-toxicity

Tobacco industry produces a large amount of tobacco waste every year, and the disposal of tobacco waste become a puzzling problem. Recycling of tobacco waste to reconstituted tobacco sheet (RTS) with suitable strength and low-toxicity was prepared in this paper. RTS with 1wt% compound adhesive that content sodium carboxymethyl cellulose and guar gum has a tensile strength (0.548 kN/m) which meet the requirements of industrial production. Strength enhancement was attributed to the synergistic effect of hydrogen bonding and physical cross-linking network through FTIR and SEM characterization. GC–MS was used to analyze the pyrolysis of RTS. The nicotine release of RTS was lower than commercial cigarettes, which significantly reduces the harmful substance. This work has been preliminarily applied to the industrial production. The production process of RTS is simple, with low water consumption and reuse of tobacco waste. Conforming to the concept of environmental protection, energy conservation, and tobacco resource recycling.

Investigation on the Lignin Removal From Tobacco Stem by a Solvothermal Method Using Ethylene Glycol as a Solvent

Summary High lignin content of tobacco stem has been addressed as a drawback for its utilization on manufacture of reconstituted tobacco sheet. Therefore, the solvothermal method using ethylene glycol was investigated for the removal of lignin from tobacco stem. It was found that the removal efficiency of ethylene glycol on tobacco stem is much lower than that achieved on wheat straw and corncob, i.e., 13.9% vs. 39.3% and 44.1%, respectively. This can be rationalized in terms of the presence of solanesol in tobacco stem, which retards the strong hydrogen bond interaction between ethylene glycol and the free hydroxyl groups present in lignin. When solanesol was eliminated by applying an n-hexane extraction procedure, 40.5% of lignin was successfully dissolved from tobacco stem. The successful removal of lignin was further confirmed by the characterizing results of SEM, FT-IR and N2-sorption. The developed method provides a promising way to attenuate the negative effects of lignin on utilization of the otherwise wasted tobacco stem for production of reconstituted tobacco sheet.

Foam forming: an effective approach to fabricate highly bulky, uniform and soft reconstituted tobacco sheets

Highly bulky reconstituted tobacco sheets (RTS) as a cellulosic product are always the pursuit of the paper industry and tobacco industry due to the advantages of improving the performance of cigarettes and the reduction in harmful substances. In this work, foam forming as a novel approach was applied in the preparation of RTS to improve paper performance. The properties of liquid foam induced by sodium dodecyl sulfate (SDS) were also investigated. Results showed that the liquid foam induced by SDS and mechanical stirring was relatively stable when the dosage of SDS was over 0.4 g/L, which can keep cellulosic fiber and tobacco fiber dispersed well during the forming process. Foam forming can endow the sheets with better uniformity, bulk, absorption and softness compared to traditional wet forming methods. Notably, the bulk of the sheets can be increased by 12% when 0.6 g/L of SDS was applied. In addition, foam forming can also help to increase the total retention rate, which was beneficial to reduce the production cost.

Effect of starch-based flame retardant on the thermal degradation and combustion properties of reconstituted tobacco sheet

In this paper, starch, distarch phosphate (DSP) and hydroxypropyl distarch phosphate (HPDSP) were used as “green” carbon sources with ammonium polyphosphate (APP) to prepare flame retardant reconstituted tobacco sheet (RTS) by paper-making process and the effect of these starch-based flame retardants on their thermal degradation and combustion properties was preliminarily investigated. Micro-scale combustion calorimetry results showed the value of the heat release of modified RTS was lower than that of pure RTS, demonstrating the restrained combustion behavior of modified RTS. TG-FTIR and TG-MS analysis indicated that the starch-based flame retardant coating promoted the char formation, inhibited char combustion and release of gaseous products except for NH3, with the relative best comprehensive performance of APP-DSP. Cigarette burning cone analysis also confirmed that the modified RTS had lower temperature and smaller burning cone volume than that of pure RTS, especially APP-HPDSP-RTS. This work could highly expand the application of starch and its derivatives in flame retardant and tobacco industry.

Preparation and Thermal Analysis of Flame-retardant Chitosan Thin Films on Ammonium Polyphosphate Treated Reconstituted Tobacco Sheet

Background: Burning temperature is one of the most important factors affecting the chemical structure of the smoke and the addition of reconstituted tobacco sheet to cut tobacco has been widely used by the tobacco industry to reduce the cost of cigarettes and the health risks of smoking. Methods: A flame retardant film, made from chitosan and ammonium polyphosphate, has been coated on the surface of the reconstituted tobacco sheet substrate by Layer-by-Layer and spray coating techniques. The thermal degradation properties and flame retardancy of these reconstituted tobacco sheets were analyzed by TG-FTIR and micro-scale combustion calorimetry. Results: It was found that the reconstituted tobacco sheet with the ratio of chitosan (5%) and ammonium polyphosphate (3%) film coating showed significant reductions in the peak heat release rate (50.7%), total heat release (35.8%) and the highest temperature in the temperature distribution diagram (77°C). The main gases released during the pyrolysis of these reconstituted tobacco sheet samples were H2O, CO2, CO, NH3, carbonyl compounds and the presence of film coating changed the formation of evolved volatile products and formed less gaseous products except NH3 during the thermal decomposition process. Conclusion: The coating film can greatly enhance the char forming ability and reduce the flammability of reconstituted tobacco sheet, and therefore, reduce the health risks of smoking with the addition of these reconstituted tobacco sheets.

Effects of ternary potassium containing intumescent flame retardant coating on the combustion and thermal degradation properties of reconstituted tobacco sheet

Reconstituted tobacco sheet (RTS) was first modified by ternary intumescent flame retardant (IFR) coating, composed of ammonium polyphosphate (APP), chitosan (CS), and potassium citrate (PC) by spraying deposition sequentially. The effects of composite coating on the combustion behavior and thermal degradation of RTS were studied by micro-scale combustion calorimetry (MCC), cone calorimetry (CC) and thermogravimetric analysis coupled by Fourier transform infrared spectrometer (TG-FTIR). MCC analysis indicated that the ternary coating presented the best flame retardancy with the proportion of APP, CS and PC at 1:1:5 (wt %). TG-FTIR results showed that APP-CS-PC coating reduced the maximum mass loss rate and the release of harmful gaseous products at the stage of char decomposition and PC promoted the formation of a potassium carbon complex, which was also supported by carbonyl compounds analysis. Moreover, for APP-CS-PC-RTS cigarette, the formaldehyde yield in mainstream smoke and the highest temperature of burning cone decreased by 67.28% and 100.1℃, respectively.

Cationic cellulose nanofibers as sustainable flocculant and retention aid for reconstituted tobacco sheet with high performance

The study that cationic cellulose nanofibers (CCNF) acts as sustainable flocculant and retention aid of precipitated calcium carbonate (PCC) for the preparation of reconstituted tobacco sheet (RTS) was carried out, thanks to the properties of CCNF. In this work, the enhanced flocculation, reflocculation and size properties of PCC flocs induced by CCNF were investigated via a focused beam reflectance measurement (FBRM) system. The physical properties of RTS such as bulk and air permeability etc. were also studied. The results indicated that CCNF could distinctly improve the flocculation and reflocculation properties of PCC with a desirable chord length in the tobacco slurry, and that the PCC retention was also increased with CCNF addition along with a slight decrease of tensile strength of RTS. The mechanisms of flocculation and reflocculation, as well as the reasons of enhanced bulk and air permeability properties ascribed to CCNF were also demonstrated.

Using cationic nanofibrillated cellulose to increase the precipitated calcium carbonate retention and physical properties during reconstituted tobacco sheet preparation

High filler retention would contribute to the good performance of reconstituted tobacco sheet (RTS), especially for adjusting its combustion speed. In this work, the cationic nanofibrillated cellulose (CNFC), as a retention additive for precipitated calcium carbonate (PCC), was applied for the RTS preparation following the conventional handsheets making. The PCC retention was increased significantly in the sheets, and the physical properties were improved obviously as well. The results showed that the PCC retention in RTS increased from 32.71% to 44.74% with the CNFC addition of 7 wt% (of oven dried PCC) when the initial dosage of PCC was 30 wt% (of oven dried pulp). The tensile strength of sheets increased from 11.92 N⋅m/g to 12.25 N⋅m/g, indicating that CNFC can play an important role in improving the physical properties of RTS. Also, the air permeability and softness could be improved greatly from 4.90 μm/pa·s to 5.64 μm/pa·s and from 114.99 to 83.33 respectively. The novel concept of CNFC acting as a retention additive of PCC for the RTS preparation was demonstrated to improve the performances of RTS products.

Flocculation - Air Flotation Treatment of Wastewater from Paper-making Reconstituted Tobacco Sheet

In order to study the remove rate of organic pollutants in wastewater from paper-making reconstituted tobacco, and flocculation-flotation method was used to pretreat wastewater was discussed in this paper. The cationic polyacrylamide (CPAM) was used as coagulant, polymeric sulfate (PFS) and polyaluminium chloride (PAC) were used as flocculant. The effects of wastewater temperature, pH value, the type and dosage of flocculant and coagulant, the pressure and inflow of the air flotation on the flocculation and sedimentation of wastewater were analyzed. Research indicates: PFS was used with CPAM with relative molecular weight of 11 million and 40% ion degree, which had the best flocculation result. At the temperature of 32 °C, the pH of 6.5, the PFS dosage of 400mg/L, the CPAM dosage of 5mg/L, the air flotation inflow of 150m3/h, the air flotation pressure of 0.35Mpa, the CODcr, SS and chroma removal rate are 65.2%, 87.43% and 72.53% respectively, which achieved the optimum effect. Under the optimum conditions, the operating cost of wastewater pretreatment by the method of flocculation – flotation was 2.72 yuan per ton.

Lignin Removal from Tobacco Stem with Laccase Improved by Synergistic Action of Weak Alkali and Tween 80

Lignin removal from lignocellulosic materials plays a great role in the utilization cellulose with high efficiency. In order to improve the quality of reconstituted tobacco sheet, lignin existed in tobacco stem was removed by enzymatic hydrolysis with laccase enhanced by weak alkali treatment together with the addition of Tween 80 into laccase treatment system. It is found that lignin was partially removed by laccase. The treatment of tobacco stem with NaHCO3 resulted in the dissolution of lignin, and hence increased the porosity and specific surface area of the pretreated tobacco stem. Consequently, laccase could access to the tobacco stem more completely. The surface activity and dispersion of Tween 80 improved laccase activity, solubilization of degraded products of lignin, and contact interface between laccase and tobacco stem. The synergistic action of laccase, weak alkali and Tween 80 improved the ratio of lignin removal significantly, reaching as high as 40.3%.

Effect of different combined moistening and redrying treatments on the physicochemical and sensory capabilities of smoking food tobacco material

ABSTRACTSmoking food tobacco material include flue-cured tobacco leaves, expanded stems, and reconstituted tobacco sheets. As the main raw material in the cigarette industry, the quality of flue-cured tobacco leaves is very important to the smoking food products. The effects of different combined moistening and redrying treatments on the physicochemical and sensory changes of flue-cured tobacco leaves have been systemically studied. This work has demonstrated that the steam moistening and low-temperature slow redrying (SM–LTSR) processes can improve the moisture content and color uniformity of tobacco leaves (p < 0.05). More importantly, the degradation of colorant and polyphenol precursors in tobacco leaves can be reduced for different redried lamina, and the average degradation amounts can be decreased by 30.63 and 22.41%, respectively. The total amount of volatile compounds can be decreased by 9.61% in comparison with the steam-water mixing moistening and high-temperature redrying (SWM–HTR) processes. We conclude that the mid-high-grade tobacco leaves should be processed through the SM–LTSR treatments to improve the color brightness, quality stability and retain flavor, while the low-grade tobacco leaves should be processed through the SWM–HTR processes to improve the processability, aftertaste and remove the offensive odor in actual threshing and redrying. This work has formed the suitable processing methods for different qualities of tobacco leaves and has laid the theoretical foundation for the quality improvement and flavor preservation of tobacco leaves.

Physical properties and thermal behavior of reconstituted tobacco sheet with precipitated calcium carbonate added in the coating process

Addition of precipitated calcium carbonate (PCC) to cellulosic products can reduce production costs and modify their physical properties. This study investigated the effects of adding PCC on the properties of reconstituted tobacco sheet (RTS), a cellulosic product. Scanning electron microscopy (SEM) analysis showed that adding PCC to the coating could modify the surface microstructure of RTS. With increasing PCC addition, the strength and tar release per cigarette of RTS decreased. However, the filling capacity, bulk, and CO release content in the mainstream smoke reached optimal values when the proportion of PCC in the coating was 8%. Thermogravimetry (TG) and differential thermogravimetry (DTG) analysis indicated that the main thermal pyrolysis stage occurred in the range of 200–400 °C, similar to cellulosic components. The Coats–Redfern equation was used to analyze the thermal pyrolysis mechanism. The fitting results showed that, in the range of 200–280 °C, the best fit model for RTS with 4 or 8% PCC was diffusion-controlled reaction (D1) with fitting correlation coefficient (r 2) of 0.9630 and 0.9576, respectively. Meanwhile, in the range of 280–400 °C, the most reliable fitting model for RTS with 4% PCC was chemical reaction (F2) with r 2 = 0.9681. One reaction model could not describe the thermal pyrolysis of RTS with 12% PCC in the main decomposition stage. The thermal kinetic parameters suggested that addition of PCC to RTS coatings could modify the thermal pyrolysis mechanism, but did not change the peak temperatures in the main thermal decomposition stage. This study demonstrates that addition of PCC to RTS coating is a promising method to improve its quality.

Effect of potassium organic and inorganic salts on thermal decomposition of reconstituted tobacco sheet

In order to deeply investigate the role of potassium in modifying thermal behavior and burning characteristics of reconstituted tobacco sheet (RTS), electrodialysis (ED) technology was employed at first to remove the main ions in the tobacco extract to reduce interference of endogenous ions. Characterization on thermal behavior of RTS treated with three organic (acetate, malate and citrate) potassium salts and three inorganic (chloride, sulfate and phosphate) potassium salts was then performed using thermogravimetric analyzer coupled with Fourier transforms infrared spectrometer (TG-FTIR) at the heating rate of 20 °C min−1. TG results illustrated that potassium decreased the peak temperature of carbohydrate pyrolysis, retarded the thermal degradation of the major components of RTS and meanwhile promoted the formation of stable char firmly depending on its chemical state. The organic potassium salts had a more significant effect on the process of char oxidation than inorganic ones with a new peak at around 570 °C. Analyses of evolved gaseous products distribution demonstrated a significant reduction of CO and CO2 during carbohydrates pyrolysis in the presence of potassium, especially organic potassium salts. Moreover, the maximum firecone temperature was also measured by Infrared thermography, and it had been found that the burning cone temperature of ED-modified RTS was averagely 13.27 °C higher than that of organic potassium treated RTS but averagely 16.57 °C lower than that of inorganic ones.

Process for coating of reconstituted tobacco sheet with citrates

The combustion property and thermal pyrolysis behavior of reconstituted tobacco sheet (RTS) with combustion improvers added to the RTS coatings were studied. The RTS coatings comprised of water-soluble extracts from tobacco stems and leaves, carboxymethyl cellulose and sodium citrate/potassium citrate. The coating was mixed and stirred by a high-speed dispersion machine for 40min, and then coated on the RTS base paper by papermaking method. Effects of citrates on the properties of RTS, such as major chemical compositions, surface microstructure, tar and carbon monoxide (CO) release per cigarette were investigated. The results showed that adding sodium citrate and potassium citrate in the coatings did not affect the main chemical contents and surface microstructure of RTS. With the ratio of potassium citrate increasing in the coating, the amount of tar and CO release per cigarette decreased significantly. Thermogravimetric (TG) analysis and the corresponding derivative thermogravimetric analysis (DTG) indicated that, compared to sodium citrated, potassium citrate accelerated the thermal degradation of RTS between 200 and 400°C, and decreased the activation energy (E) according to the kinetic analysis results of Coats–Redfern model. Therefore, potassium citrate may become a potential burning additive controlling CO and tar release in mainstream smoke of RTS.

TGA/FTIR study of the pyrolysis of diammonium hydrogen phosphate–tobacco mixtures

Diammonium hydrogen phosphate (DAP) is commonly used as a flavor ingredient of commercial cigarettes. In addition, among its other uses, it is employed to expand the tobacco volume, to manufacture reconstituted tobacco sheet, and to denicotinize tobacco. However, the use of DAP as a cigarette ingredient is a controversial issue. Some authors have stated that ammonium compounds added to tobacco increase smoke ammonia and “smoke pH”, resulting in more free nicotine available in the smoke. On the other hand, other researchers have reported that the larger ammonium content of a cigarette blend due to the presence of DAP was not reflected in increased smoke ammonia. In this work, the thermal behavior of DAP, tobacco and DAP-tobacco mixtures has been studied by TGA/FTIR. The chemical processes involved in the different pyrolysis steps of DAP have been suggested. Marked changes in the pyrolytic behavior of both, tobacco and DAP have been detected when analyzing the behavior of the mixtures. A displacement of the decomposition steps mainly related to the glycerol and lignin from tobacco toward lower temperatures has been observed, whereas that associated with cellulose is displaced toward higher temperature. Additionally, no peak corresponding to the phosphorous oxides decomposition has been detected in the curves relating to the DAP-tobacco mixtures. All these features are indicative of the strong interactions between DAP and tobacco. The FTIR spectra show no significant qualitative differences between the qualitative overall composition of the gases evolved from the pyrolysis of tobacco in the absence and in the presence of DAP. Nevertheless, depending on the temperature considered, the addition of DAP contributes to a decrease in the generation of hydrocarbons and an increase in the formation of CO, CO2 and oxygenated compounds in terms of amount generated per mass of pyrolysed tobacco.

Effects of common ammonium salt on the thermal behavior of reconstituted tobacco sheet

Understanding the role of chemical burn additives on modifying the toxic gaseous constituents and thermal behavior of reconstituted tobacco sheet (RTS) has recently taken center stage through a number of initiatives. In this current study, the effects of ammonium chloride (AC), ammonium sulfate, diammonium phosphate, and monoammonium phosphate on the formation of evolved gaseous products, specifically carbonyl compounds and thermal behavior were investigated. Results on cigarette smoking tests revealed that ammonium salt was a potential burn additive to reduce carbonyl compounds delivery in the cigarette mainstream smoke of RTS. The yield per puff of carbonyl compounds of pure RTS was decreased from 247.8 µg to 133.30 µg with the incorporation of AC. Thermogravimetric analysis (TG) and differential scanning calorimetry (DSC) were used to investigate the thermal decomposition of RTS. TG results revealed that the incorporation of ammonium salt into RTS could improve the thermal stability of RTS. The DSC results showed that the maximum exothermic peak was drastically decreased with the addition of ammonium salt, for example, from 14.8 mW mg−1 of pure RTS to 10.27 mW mg−1 of AC-RTS. Results on Fourier transform infrared spectrometer (FTIR) which was employed to investigate the generation of evolved volatile products showed that these four ammonium salts as burn additives were efficiently high enough to decrease the formation of gaseous products. From our findings, compared with the virgin RTS and other three modified RTS, AC-RTS could significantly decrease the yields of nicotine and phenolic compounds in the cigarette mainstream smoke of RTS.

Diversity analysis of the bacterial community in tobacco waste extract during reconstituted tobacco process.

Reconstituted tobacco sheet process has been developed to treat and reuse tobacco wastes in the industry. During this process, microorganisms in original and concentrated tobacco waste extract (TWE) might play important roles in the final quality of the reconstituted tobacco. However, microbial communities in TWE remain largely unknown. In the present study, the Roche 454bar-coded pyrosequencing was applied to analyze the bacterial community structure in samples. Comparison based on 16S rRNA gene sequences showed that the original and concentrated solutions of TWE harbored abundant bacteria probably resistant to the acid, high nicotine concentration, and high osmotic pressure environment. The dominant phyla were Firmicutes and Proteobacteria. Lactobacillus and Lysinibacillus were the dominant genera of Firmicutes. The most interesting genus of Proteobacteria was Pseudomonas. It is the first time to reveal the bacterial diversities on the TWE samples from the process of reconstituted tobacco sheets.

Rheological property of reconstituted tobacco coatings

Reconstituted tobacco sheets are widely used in the tobacco industries to reduce the harm of cigarettes and considered as a comprehensive utilization method for tobacco wastes. Reconstituted tobacco coating is one of the core technologies determining the reconstituted tobacco sheet quality. The main component of reconstituted tobacco coating is water extracts from tobacco wastes. The effects of different dosages (0.1%, 0.3% and 0.5%) of carboxymethyl cellulose (CMC) and cationic guar gum (CGG) on the properties of coatings were studied. Reconstituted tobacco coating exhibited a prominent shear-thinning property at the condition of low–medium and high shear rates. Classical flow models Herschel–Bulkley (H–B), Power-law and Cross models were used to analyze the coating rheological properties. At the condition of low–medium and high shear rates, H–B and Power-law model were more satisfactory to describe the flow behavior than Cross model. SEM analysis showed that when the dosage of rheological agent (CMC) was 0.1%, reconstituted tobacco sheet obtained good coating surface structure.

Effect of exogenous softwood on thermal decomposition of reconstituted tobacco sheet

In recent years, reconstituted tobacco sheet (RTS) has played an increasingly vital role in reducing tumorigenicity for tobacco industry. In this paper, two plant fibers of tobacco pulp (TP) and softwood pulp (SP) were added independently as strengthening agents during the paper-making process to manufacture RTS (TP-RTS and SP-RTS). The effects of exogenous SP on the CO yield in cigarette mainstream smoke, thermal behavior, and gaseous products evolution properties of RTS were evaluated and compared with TP. The CO yield in cigarette mainstream smoke was studied using smoking machine and CO analyzer. The thermal behavior of two RTS was studied by thermogravimetric (TG) analysis, and the gaseous products were investigated by Fourier transform infrared spectrometer (FTIR). CO yield in cigarette mainstream smoke results demonstrated that SP-RTS (3.16 mg per puff) presented higher CO yield per puff than TP-RTS (2.83 mg per puff). TG analysis results demonstrated that the maximum mass loss rate of SP-RTS (23.3 % min−1) was drastically higher than that of TP-RTS (15.8 % min−1). FTIR results illustrated that SP-RTS presented stronger absorbance intensity associated with generation of more gaseous products than TP-RTS. In the thermal decomposition stage, the maximum mass loss rate of SP (78.6 % min−1) was clearly higher than that of TP (38.4 % min−1), and SP increased the generation of gaseous products compared to TP.