Synthesis Of Biosorbitol Polycarbonate And Conductive Performance Of Copolymer

Bisphenol A（BPA）is one of the synthetic materials of polycarbonate（PC）,while it has toxicity and estrogen effects and comes from non-renewable petroleum,thus causing great adverse effects on human health and the environment of earth.At present,biomass isosorbide（IS）was used to replace BPA,and synthesize biobased poly（isosorbide carbonate）（PIC）with diphenyl carbonate（DPC）.PIC was considered as the most likely alternative to traditional PC because of its excellent mechanical strength,optical characteristics,and resistance to wear and heat.In order to reach the level of PC industrial application,the molecular weight of PIC must be high enough and the production process must be simple and low cost.Due to the rigidity of IS in PIC structure unit and the high viscosity of PIC melt,it is not easy to process finished products and the application field is limited.Therefore,it is necessary to modify PIC to expand its application range.In view of the above deficiencies,it was found that the high efficiency catalyst can be used to prepare high molecular weight PIC in this paper and industrial grade PIC production,and polyether-type polycarbonate was prepared as polymer electrolyte by using ether-oxygen group in IS and other diols.The main contents were as follows.In second chapter,we designed four lithium salt catalysts and compared the effects of catalysts with different anionic on the efficiency of PIC synthesized by melting polycondensation of IS and DPC.It was found that lithium lactate（Li LAc）as catalyst had the best catalytic efficiency.The optimal polymerization conditions were selected by comparing different melting and polycondensation reaction conditions,PIC with M_w of105.0 k Da can be prepared for 1.5 h,the transmittance of PIC film is 90%and the tensile strength is 42.5 MPa.Finally,the mechanism of the catalyst on the substrate and the structure of the intermediate were analyzed by means of nuclear magnetic resonance,intermediate capture and DFT simulation.It was found that the synergistic effect of hydrogen bond formation between IS and Li LAc,as well as the electrostatic interaction between catalysts,enables Li LAc to efficiently catalyze PIC synthesis.In the third chapter,we designed 5 kinds of aliphatic monomers and controlled the proportion of the monomers to synthesize different poly（aliphatic isosorbide carbonate）s（PAICs）.It was found that the straight chain copolymerization unit had better flexibility than the ring structure.The reduction of IS content was beneficial to the increase of molecular weight of PAICs,and the T_g control of copolymerized polycarbonate could be realized.Introducing tetraethylene glycol（TTEG）for copolymerization to obtain polyether polycarbonate（PTTIC）,reducing the T_g of PTTIC and adding Li TFSI can significantly improve the conductivity.The conductivity of Li TFSI with 30 mol%in PTTIC is up to 1.0×10^-3 S·cm^-1 at room temperature,which can be used as a polyelectrolyte.