Study On The Preparation And Application Of Lignin-based Polyvinyl Acetate Polymer

In this paper,lignin-based polyvinyl acetate is prepared by copolymerization of modified lignin and vinyl acetate,which is used as a bio-based coating in paper packaging materials.An electrostatic spinning method and a hot pressing process are utilized to prepare a composite fiber membrane of lignin-based polyvinyl acetate and polyvinyl chloride blending with N,N-dimethylacetamide(DMAc)as a solvent.Its physical properties and the electrochemical performance were checked and compared with the commercial polypropylene separator(PP)and PVC film.First of all,in order to replace other polymers and vinyl acetate to prepare polyvinyl acetate,the biomass resource sodium lignosulfonate was modified.In order to increase its chemical activity,it is aminated with diethyltriamine,and vinyl chloride acetate is utilized.The VAc was grafted onto aminated lignin with vinyl chloroacetate,and the grafting temperature,time and p H were discussed,and the best grafting conditions were discovered.The suspension copolymerization method was used to prepare copolymers of LVAc and VAc with different mass ratios,and the elements Analysis,HNMR,XPS,FTIR,GPC,DSC and TGAwere used to study the chemical structure and thermal properties of the synthesized copolymer.Next,the prepared P(VAc/LVAc)was applied as a bio-based coating to paper packaging materials,and the effect of lignin addition on the properties of coated paper was studied.Then,prepared P(VAc/LVAc)and PVC are blended,the P(VAc/LVAc)/PVC composite film is written by the electrostatic spinning method,and the spinning optimal process parameters are explored.Finally,the P(VAc/LVAc)/PVC composite diaphragm was hot-pressed at 16 MPa,100°C,assembled into a lithium-ion battery in an argon glove box,and its electrochemical properties such as cycle life and rate were studied after standing 24 h.Concluded as following:1.During the process of aminated lignin,the grafting rate can up to 47%.The best grafting time is 6 h,the best p H is 9,and the best reaction temperature is 40°C.The content of lignin in P(VAc/LVAc)has a significant effect on Mw(increased to 190000g/mol),which will affect other properties of P(VAc/LVAc).The research results show that TGA shows that P(VAc/LVAc)still has good thermal stability up to 367°C,while PVAc has the greatest degradation at 290°C.The results prove that high thermal stability Sexual P(VAc/LVAc)copolymer was synthesized successfully.2.The paper coated with P(VAc/LVAc)copolymer,when the addition of LVAc reaches 10%,the tensile index and break-resistance index reached the maximum value,reaching 81.60 N.m/g and 5.29 k Pa.m~2/g,respectively.The results show that it can improve the hydrophobic properties of the paper,and the coating of the copolymer improves the air barrier properties of the paper.And because of the addition of lignin,it also improves its UV absorption capacity.3.Electroscope P(VAc/LVAc)/PVC composite diaphragm,the average fiber diameter is 320 nm,the experimental environment temperature is controlled at 20-35°C,and the humidity is controlled between 30%-50%.The best spinning parameters are:voltage is 26 KV,feed rate is 0.8 m L/h,receiving distance is 15 cm,collecting drum speed is 1000 rpm/min4.The P(VAc/LVAc)/PVCcomposite diaphragm is hot-pressed at 100°C.The fibers are bonded together,showing a good three-dimensional network structure,which is mounted into a lithium ion battery,showing excellent liquid absorption performance,high porosity and good electrochemical performance.Its porosity can reach 60.56%,and the liquid absorption rate can reach 326.67%,which is three times that of PP film.5.After 100 cycles at a current density of 0.2 C,the discharge capacity retention rate of the lithium-ion battery is 91%,indicating that the battery has excellent electrochemical performance.On the other hand,the P(VAc/LVAc)/PVC composite diaphragm compared with PVC film and PP film,the dimensional thermal stability of the P(VAc/LVAc)/PVC composite film is obviously improved.