Preparation Of Functionalized Composite Films By Modifying Plant Fibers In Ionic Liquids

Plant fiber is a type of renewable biomass,with the characteristics of biodegradation,biocompatibility and good mechanical properties.But it is insoluble in water and general organic solvents and complex fibrous structure,resulting in a certain degree of difficulty in plant development and utilization.Due to the above problems,we used physical and chemical methods to modify the plant fiber in ionic liquid media,and prepared the functional composite fiber film and other materials.In this work,Four kinds of ionic liquids were prepared using one-step method such as 1-ethyl-3-methylimidazolium phosphate([EMIM][DEP]),and the dissolution performance of the microcrystalline cellulose was measured.The results showed that [EMIM][DEP] had the good solubility to cellulose with 100% the dissolution rate at 90 ? for 1.5 h.For the first time,the method of ultrasonic assisted NaOH solution swelling was utilized to extract cellulose from biomass.The results showed that the weight loss rate of plant straw after ultrasonic expansion and NaOH solution swelling was 15.8% higher than that of pure NaOH,and the cellulose content as high as 89.5%.The dissolution rate of plant fiber could be 100% in [EMIM][DEP] with the solid-liquid ratio of 1: 30 at 90 ? for 2 h.For the first time,in the ionic liquid plant fiber and silk fiber(SF)was modified by carboxylation and graft copolymerization.In a short time to improve the carboxyl content and grafting rate,the carboxyl content of carboxy mulberry fiber(CMF)was 12.3% at 90 ? for 2 h,and the grafting rate of CMF and SF was 28.9% at 60 ? for 2 h.We prepared biomass film using drooling method such as CMF / SF composite film and mulberry fiber / bamboo fiber(MF / BF)composite film.Physical and chemical properties,such as water absorption,swelling rate and tensile strength of the material were measured.Morphology of biomass films were observed by SEM,and the biomass films were characterized by FTIR,XRD and TGA.The results showed that the CMF / SF composite film has strong water absorption and swelling ability,and the water absorption and swelling rate are 485% and 252% respectively.MF/BF composite film has good thermal stability and mechanical properties,the pyrolysis temperature is 269 ?,the tensile strength is 33.2 MPa;Plant fiber prepared by ionic liquid dissolution and regeneration,resulting variation from type I cellulose to type II cellulose;CMF / SF composite film and MF / SF composite film surface is relatively smooth,high integration,with good material compatibility,and could be used in the field of food,medical and other fields for its potential application.