Preparation of lignin/nanocellulose hybrid particles by co-precipitation method
As natural energy sources,cellulose and lignin are the most abundant renewable resources in nature.Inspired by the symbiotic and entangled structure of cellulose and lignin in natural wood,the research and exploration of lignin/cellulose hybrid particles aim at recombining multi-dimensional new materials based on the micro-nano elements of forest biomass,which is one of the effective means to enhance and expand the high-value utilization of forest biomass.Based on the dissolution-precipitation method,this study used two solvents,tetrahydrofuran,and anhydrous ethanol,to dissolve lignin sulfonate separately.Cellulose nanofiber(CNF)suspension was then instantly added to the solution,causing phase separation in the lignin solution,and achieving rapid preparation of lignin micro-nanospheres(LNS),while mixing with nano cellulose to prepare stable and uniformly dispersed LNS/CNF hybrid particles in one step.The effects of different solvents,different CNF concentration suspensions and different drop rates on the stability,particle morphology,size,surface tension and film formation properties of LNS/CNF hybrid particle suspensions were discussed.The characterization of LNS/CNF hybrid particles and the obtained films included following procedures:the size and microstructure of LNS and CNF were observed by atomic force microscopy(AFM),20 samples were selected from the AFM diagram of LNS and CNF,respectively,and their sizes were measured and analyzed manually.The LNS/CNF suspension prepared with tetrahydrofuran(CNF mass ratio was 0.5％)was diluted to 1/10 000,and the solution of uranyl acetate was added for staining.After the ultrasound treatment,the suspension was added to carbon net for drying,and then characterized by the transmission electron microscopy(TEM).Scanning electron microscopy(SEM)was used to observe and verify the microstructure of LNS/CNF hybrid particles and the obtained films.The surface tension of LNS/CNF hybrid particle suspensions prepared by different methods was measured by an optical contact angle measuring instrument.The results showed that the difference of the dissolution behavior of lignin sulfonate in different solvents,the concentration and drop rate of CNF suspension would affect the stability,morphology and size of the hybrid particles,and the size and morphology of the LNS/CNF hybrid particles treated with tetrahydrofuran were more uniform,the optimum CNF mass ratio of the reaction was 0.5％,and the size of the LNS/CNF hybrid particles was the most uniform.By controlling the dripping speed,the particle size can be effectively controlled and the controllable preparation of LNS can be realized.When maintaining a constant concentration of CNF,it was observed that a faster drop rate corresponded to improved properties of the LNS/CNF hybrid particles and thin films.
万方数据
维普
