Study On Preparation And Properties Of Sodium Lignosulfonate-based Functional Materials

Lignin,a kind of renewable biomass materials with complex aromatic structure,is commonly found in plant.However,the complex and variable of functional groups and spatial structure have great influence on its properties,which limit the application areas of lignin.Therefore,lignin is treated as a waste produced from the paper and pulp industry.Today,the limited resources of fossil fuel and the environmental concerns caused by synthesized polymer materials.It should develope new functionally materials based on lignin and its derivatives ares going to continue to grow in importance.In this paper,the sodium lignosulfonate(LS)based material was prepared in order to enlarge its application fields,the preparation mechanism and material properties were investigated.The main thesis content and innovative achievements include the following parts:Chapter 1,the basic structure unit of lignin and its existing form in the plant body are introduced,the extraction methods from waste pulp in the paper industry are also reviewed.Then,the research progress of lignin functionalized materials is emphasized in the field of material application.Chapter 2,sodium lignosulfonate(LS)was grafted on to soy protein isolated(SPI),epoxy chloropropane(ECH)as crosslinking agent,and the sodium lignosulfonate-soy protein isolated placed material(LS-SPI)was prepared.The solubility of sodium lignosulfonate in different solvents and the effect of p H on solubility were measured.The structure of LS-SPI material was characterized by SEM and FT-IR,the formation mechanism of grafted biomass material was studied,and the drug release efficiency of LS-SPI material in different p H solutions was also simulated.The results indicated that the LS-SPI material had slow release speed and high release rate on the model drug rhodamine B(RB)and riboflavin,and the sustained release effect showed p H-sensitivity.Chapter 3,based on the three-dimensional network structure of sodium lignosulfonate,using acrylamide(AM)and hydroxyethyl methacrylate(HEMA)as monomers,N,N'-Methylenebisacrylamide(MBA)as crosslinking agent,the sodium lignosulfonate hydrogels(LS-P(AM-HEMA))was prepared in the presence of free radical initiator.The structure of hydrogel has been characterized by using SEM and FT-IR,and the forming mechanism of hydrogel was studied.The compressive ability,swelling properties in different solvents of hydrogel and the influence of salt concentration on swelling performance,deswelling kinetics,reswelling kinetics and water retention rate were investigated,with the slow release ability of the product discussed.The results show that the LS-P(AM-HEMA)hydrogel has excellent mechanical performance and flexibility,the different solvents have influence on swelling rate,and able to swelling again,and the hydrogel also can reduce moisture to evaporate.In different solution with different p H,the hydrogel showed different release properties and p H-sensitivity to RB and BSA.Chapter 4,using sodium lignosulfonate as stabilizer,methacrylic acid(MAA)and styrene(St)as monomers,the LS-based copolymer microsphere(LS-PMS)was prepared through the free radical polymerization.The LS-PMS microspheres were characterized by SEM and FTIR,and the formation mechanism of microspheres was discussed.Then the particle size distribution,emulsification performance and emulsion droplet size of microspheres were investigated.The results show that the copolymer microspheres particle size distribution is narrow,with the adding of LS,emulsion has better emulsifying performance,and the emulsion droplet size is smaller.In addition,the emulsion shows p H-sensitivity.Increasing the salt concentration play an active role in emulsifying performance.In conclusion,new sodium lignosulfonate based materials are prepared by using its structure characteristic,and the products have drug loading and slow-release properties,emulsifying properties,thus,the application scope of lignin are enlarged.This research achieves the goal of waste natural polymer reused,reduces environment pollution at the same time.