Study On Synthesis Of Bacterial Cellulose From Tobacco Waste And Its Application In Flexible Conductive Materials

Bacterial cellulose（bacterial cellulose,BC）has excellent tensile strength and three dimensional nano-scale porous network structure.Flexible and highly conductive nanocomposites synthesized on BC substrate have the advantages of light weight,high flexibility and electrical conductivity,and have broad application prospects in electronic devices.In this study,tobacco waste was used as substrate to produce BC.Then,the low-cost BC-based flexible and highly conductive nanocomposites were synthesized through a simple method.The electrochemical and structural characterization results showed that the as-synthesized composites have good electrochemical and physical properties.Results of this study provide a way to obtain low-cost BC-based flexible and highly conductive nanocomposites.The main research contents are as follows:（1）Tobacco waste was extracted by using different concentration of acetic acid.In order to obtain the ideal substrate for BC production,the total sugar content,nicotine and furfural in the tobacco extract were detected.After optimizing the extract condition,2%acetic acid,120℃and 90 min are the optimal conditions for the hydrolysis of tobacco waste extract.Meanwhile,when 6%activated carbon was added to the extract,the concentration of nicotine and furfural reached the lowest which was beneficial to increase the BC yield.The fermentation conditions were optimized by response surface analysis and orthogonal experiments.The results showed that the BC yield reached highest（8.35 g/L）when the temperature was 32℃,p H 6.0 with 3%inoculation amount.A method for producing BC from tobacco waste hydrolysate was established.（2）The BC-Sn O₂was firstly synthesized by spraying Sn O₂on BC films when growing in the media,Then the BC-PPy and BC-Sn O₂-PPy were prepared by impregnation on BC or BC-Sn O₂films.The structure of these composites was characterized by FTIR、XRD、TGA and FE-SEM.It was found that large number of Sn O₂particles were uniformly distributed in three dimensional reticular porous structure of bacterial cellulose in the as-synthesized BC-Sn O₂and BC-Sn O₂-PPy membranes.The PPy were also uniformly coated onto the BC fibers in the BC-PPy and BC-Sn O₂-PPy membranes.The thermal stability of all as-synthesized composites was improved compared to that of pure BC films.The electrochemical performance and conductivity were evaluated by cyclic voltammetry,AC impedance and four-probe tests.For these composites,conductivity,specific capacity and conductivity of resistance were detected.For pure BC film,no conductivity was observed,the specific capacity is 7.47 F/g,and the conductivity of resistance is 692.1Ω.The conductivity increased to 0.077 S/cm for BC-Sn O₂,1.152 S/cm for BC-PPy,and 7.246 S/cm for BC-Sn O₂-PPy.The specific capacity increased to 179.55 F/g for BC-PPy,66.02 F/g for BC-Sn O₂,and 484.21 F/g for BC-Sn O₂-PPy.The conductivity of resistance were decreased to 273.5Ωfor BC-Sn O₂,57.9Ωfor BC-PPy and 40.4Ωfor BC-Sn O₂-PPy.At the same time,the shapes of CV curves of all composites remain stable under different bending deformations,indicating that these nanocomposites have excellent elasticity and recoverable conductance properties.The above results show that BC-based flexible conductive materials were synthesized by adding Sn O₂or polypyrrole particles onto the BC films.Among the as-synthesized nanocomposites,BC-Sn O₂-PPy owns best electrochemical properties,is supposed to be applied in the field of flexible electronic devices.（3）In order to obtain more excellent flexible conductive materials,the nanocomposite film were prepared by replacing tin oxide with antimony oxide（ATO）.The BC-ATO and BC-ATO-PPy were prepared.Similarly,the as-synthesized nanocomposites were characterized by FTIR、XRD、TGA and FE-SEM.The electrochemical properties of these composites were also investigated.Results showed that the conductivity of BC-ATO film material increased to 10.236 S/cm,the specific capacity increased to 563.90 F/g,and the resistance decreased to 83.6Ω;BC-ATO-PPy films’conductivity increased to 16.532 S/cm,specific capacity increased to 681.30 F/g,resistance decreased to 32.4Ω.Meanwhile,the shape of the CV curves also kept stable under different bending deformation,indicating those composites have excellent flexibility.The above results suggested that the conductivity of the BC-ATO-PPy film is significantly higher than that of the BC-Sn O₂-PPy film,and a better flexible conductive material is obtained.