| Cellulose is the most abundant polysaccharide in nature and has become a research hotspot.However,cellulose is mainly derived from wood,which is not only costly and ecologically damaging.Therefore,in this study,corn straw was used as a raw material to purify cellulose and cellulose was dissolved using a system of lithium chloride?LiCl?/N,N-dimethylacetamide?DMAc?to obtain a regenerated cellulose membrane.The morphology and structure of the plain film were characterized.The effect of the binding state of water and water on the molecular dynamics of cellulose and cellulose membrane was studied.The application of cellulose membrane in the preservation of tea was explored.And get the following conclusions:1.The main components of corn stalk were measured experimentally,in which cellulose content was the highest,reaching 49.23%,lignin and hemicellulose content were 26.01%and 22.76%,respectively.2.The corn straw was treated with 5%potassium hydroxide solution and acidifiedsodium chlorite solution at acetic acid at 75°C respectively,and the obtained cellulose had a purity of 90.46%and a crystallization index of 40.66%.The use of saturated salt solution to control the relative humidity obtained by the relative humidity of cellulose,and to study the effect of water content on the dielectric relaxation of cellulose.It is found that the change of the moisture content of cellulose has a nonlinear relationship with the change of humidity,of which more than 90.00%of the water exists in the form of bound states,in which tightly bound water directly participates in the movement of partial segments of cellulose,which makes?relaxation.Relaxation time changes significantly,and loosely bound water can not only affect the segmental movement of macromolecules,but also can significantly affect the behavior of?wet relaxation.3.Cellulose solution was prepared by dissolving cellulose with LiCl/DMAc system.The prepared cellulose film was dense,with good light transmittance and low crystallinity.Membrane drying process was used to obtain cellulose membrane samples with different water content,and the influence of water content change on the dielectric relaxation was studied.The water content of the cellulose film was found to be linear with the drying time.The water binding state and the effect on the dielectric relaxation of the fiber membrane are similar to those of water on cellulose.4.Within one week after storage,the preservation effect of cellulose film on tea leaveswas not significantly different from that of commercially available tea bags,and afterstorage for 60 days,the tea polyphenol content of tea leaves packed with cellulose film was lower than that of tea.The tea packaged bag had a high rate of 22.89%,while the DPPH clearance rate was 6.09%higher.The refreshment of cellulose film was significantly better than the tea bag. |
PDF Full Text Request