| Polymeric Ionic Liquids(PILs) is polymerized by the ILs containing double bond or otherpolymerizable group and has a long chain polymer. PILs inherits many excellent properties fromILs after polymerization and the stability of ILs has effectively improved during the liquid to solidphase transition. PILs has some unique physicochemical properties, such as negligible vaporpressure, higher thermal stability than ILs and wide electrochemical window, also the ionicconductivity will have a significant change when PILs absorbing vapour and organic solvent or gas,thus PILs is expected to be applied in the development of the novel gas-sensitives.Bacterial Cellulose(BC) is a kind of biomass cellulose with excellent mechanical propertiesand flexibility. Because of its hyper-fine3D network structure, high BET specific surface area andthe abundant active hydroxyl group, when compositing with other polymers, it can synthesis nano-functional composite materials with specific morphology through template effect and hydroxylguiding. Also BC can be used as an excellent base material to obtain functional composite materialwith outstanding integrated performance.In this paper, we use radical polymerization of ILs,1-vinyl-3-Ethyl imidazole bromide (VEIM-Br), which containing unsaturated bond to obtain PILs, and used BC’s3D network as thepolymerization template to get the PILs/BC membrane and studied the influence of the complexmethod, monomer concentration, initiator concentration on the structure and properties of theprepared membrane. We also did further research on the composite membrane’s conductiveproperties, response to ammonia gas sensing performance, and explored its application.BC/PVEIM-BF4composite film has been successfully prepared by ion exchange. We also studiedon its water absorption and conductive properties. Specific studies are as follows:(1) PVEIM-Br were prepared via free radical polymerization. The effects of different reaction conditions, such as initiator species and concentration, reaction temperature, reaction time, on thewater-absorbing quality, thermal properties of PVEIM-Br were investigated in this paper. And theoptimal polymerization process of PVEIM-Br was obtained after discussion.(2) Based on the optimal polymerization process of PVEIM-Br, the PVEIM-Br/BC compositemembranes were prepared via in situ polymerization, dip coating and pulp blend. And the surfacemorphology, mechanical properties of PVEIM-Br/BC composite membranes were investigated anddiscussed. The PVEIM-Br/BC composite membranes obtained via in situ polymerization show thebest mechanical properties in the above mentioned three methods. When the monomer concentrationis0.5mol/L, the breaking strength of PVEIM-Br/BC is15.4MPa, breaking elongation is3.22%,specific surface area is17.9m2/g. The electrical resistivity of the composite film is around5.8×103Ω·cm. It has a rapid response in ammonia environment. The resistivity of PVEIM-Br/BC canachieve equilibrium in about60s and remain stable. The composite film has a good reproducibility.However composite film can be greatly influenced by humidity. To solve this problem, we preparedthe PVEIM-BF4/BC composite films through ion exchange. The water absorbing was studied. Afterion exchange, PVEIM-BF4/BC film’s24h water absorption is1.64%. The environmental stabilityof the film increases a lot due to humidity. |
PDF Full Text Request