Preparation And Function Of Composite Of Nanocellulose,Chitosan And Silk Fibroin

As a green environmental protection material,biomass fiber has many advantages,such as wide sources,biodegradability and good biocompatibility.At present,the research groups have developed a variety of methods to obtain the biomass nanofibers,including the cellulose nanofibers,silk nanofibers and chitin nanofibers,and has realized the functional modification of these nanofibers,making the biomass nanofibers and their derivatives materials.It has been applied in many popular fields.In this paper,the nanofibers obtained from wood were used as raw materials,and based on the structure and functional characteristics of nanofibers,a nanoscale hydrogel membrane was prepared by a fast method.The low-cost filter membrane had a stable filtration effect.Secondly,the nanocellulose/chitosan composite aerogel materials were prepared,and the composite aerogel materials were systematically presented.The oil-water separation efficiency was characterized and tested.Then a kind of nanocellulose/nano silk fiber composite membrane with dense structure was prepared with the aid of the micro structure of nano silk fiber.Finally,a double-layer composite membrane material with double stimulus response was prepared by combining nanocellulose with a functional recombinant silk protein polymer.The main work of this paper is as follows:(1)By utilizing using nanocellulose as the main raw material,nanocellulose hydrogel membrane with three-dimensional network structure was quickly prepared by simple vacuum filtration method,which was used for filtration and separation of nanoparticles in solution.The nanofibers hydrogel membrane has the characteristics of super hydrophilicity and unique multilayer high porosity structure,and its water can pass quickly.The nanocellulose membrane has a certain pressure resistance,and can maintain a stable water flux and high particle interception efficiency in the filtration process of high concentration and large volume of 20 nm TiO2 particle aqueous solution.At the same time,the diameter and size of Au and Ag nanoparticles which can be effectively intercepted and filtered by the membrane were evaluated.In this study,the nanofiltration hydrogel membrane was compared with the other 18 kinds of membrane which had been reported in raw materials and filtration efficiency.(2)A freeze drying method was used to prepare nano cellulose/chitosan composite aerogels with high porosity and three-dimensional network structure,using nano cellulose and chitosan as raw materials.Among them,nanoscale cellulose,as a skeleton structure unit of composite aerogels,can be combined with chitosan through hydrogen bonding force,giving good mechanical compressive properties of composite aerogels.By adjusting the mass fraction of nano cellulose/chitosan composite aerogels and the content of nano cellulose,the mechanical properties of the composite aerogels were evaluated,and the compress modulus of the aerogels was compared with those of other materials reported.In addition,the morphology,thermal stability,water and oil separation efficiency,pressure bearing capacity and biocompatibility of the composite aerogels were characterized and tested.(3)An uniform and stable nano silk fiber solution was prepared by the self-assembly method of ethanol induced regeneration of silk protein,and it was mixed with nano cellulose solution in a certain proportion.The nano cellulose/nano silk protein fiber composite membrane was prepared by vacuum filtration.The thickness of the composite membrane can be adjusted by adjusting the volume of the composite solution used in the preparation process.When the volume of nano cellulose/nano silk protein fiber composite solution increases,the thickness of the composite membrane increases,which can effectively improve the filtration performance of the composite membrane for small size dyes.The composite membrane with negative charge on the surface has a certain adsorption effect on the dye with negative charge,so as to improve the filtration and interception effect on the dye with positive charge.In addition,the biocompatibility and biodegradability of the composite membranes were characterized and tested.(4)The recombinant silk elastin protein like polymer recombinant protein with environmental stimuli responsive properties was prepared by genetic engineering technology.Recombinant protein hydrogels were prepared by enzyme linked reaction.The volume of the recombinant protein hydrogel can shrink in response to changes in external temperature and salt ion concentration,and has a stable recovery property.A double layer hydrogel composite membrane system was prepared by combining the recombinant protein hydrogel with the nano cellulose membrane prepared by vacuum filtration.The response of the double-layer composite membrane to the temperature and the concentration of salt ion was also analyzed.The double-layer composite membrane can respond sensitively to the changes of temperature and salt ion concentration,and with rapid deformation.By adjusting the volume of the recombinant protein hydrogel and rationally constructing the shape of nano cellulose thin,the deformation direction of the bilayer film system can be controlled to achieve more complex and controllable braking behavior.