Preparation And Properties Of Natural Plant Nano-cellulose And The Films From Wood And Apocynum Venetum Fibers

Plant cellulose,as one of the natural polymer materials,is rich in natural resources with environmentally friendly,renewable and biodegradable properties.With the global issues such as mass oil consumption and environmental pollution etc.arising,the application and development on natural plant cellulose have been regaining popularity.However,the intrinsic disadvantages of cellulose such as low chemical corrosion resistance and limited strength limit its application scope.However,in the nano-scale range,obtaining nano-cellulose with high aspect ratio and surface area could provide better properties and wider application range,which is now becoming research hotpot.In this thesis,wood powder,as raw materials was first explored for preparation of nanocellulose.Based on the forementioned experience,the preparation and characterization of nanocellulose were done by using apocynum venetum fibers collected from Xinjiang as the raw materials.After that,two types of nano-cellulose suspension above were prepared into films with different thicknesses.For these films,the possibilities of using them as lithium ion battery separators were discussed by testing and analyzing their properties.The detailed research contents are listed as follows:For the first part,the preparation method of nano-cellulose was explored by using chemical and mechanical treatments for the wood powder.Based on the experiences,the apocynum venetum natural fibers as raw materials were prepared into nano-cellulose as well,which has not been reported in literature.The diameters of most fibrils in the nano-cellulose prepared from the above two kinds of raw materials are focused on 10-100 nm,however the diameter distributions showed slight differences.Apocynum venetum nano-cellulose had finer diameters and more average diameter distribution compared with the wood nano-cellulose.After that,the nanocellulose suspension was freezed and the surface morphology was observed by FESEM,and the change in elements was analyzed by FTIR.In the second part,the apocynum venetum nano-cellulose suspension was prepared into nano-cellulose films by using the mold method.Different thicknesses(15?20?30?45?70?m)were obtained by controlling the amount of suspension.In addition,the wood nano-cellulose film with the thickness of 20?m was used for comparison.The tensile and light transmittance properties were tested to explore the influence of film preparation method and thickness.Based on the apocynum venetum nano-cellulose film with the thickness of 20?m,the possibilities as the lithium ion battery separator were explored.The results showed that the Apocynum Venetum nano-cellulose film has better heat resistance and liquid absorption rate compared with the commercial Celgard2400 separator.However,the ion conductivity and interface impedance are required to be improved,which could be improved by increasing the porosity.In summary,the preparation of nano-cellulose and nano-cellulose films has been discussed and the corresponding films have also been prepared and the properties were tested.And the possibilities for the Apocynum Venetum nano-cellulose as lithium ion battery separator were discussed.The success of preparation of Apocynum Venetum nano-cellulose provides more choices for the nano-cellulose raw materials.Then,the corresponding preparation parameters and experimental results provide some data support for this kind of research and application.In addition,the application of lithium ion battery separator can help to broaden the application scope of the Apocynum Venetum nano-cellulose.