Study On The Structure And Properties Of Cellulose-laponite Composite

Cellulose is the most abundant natural polymer in the nature,which has regular structure and a lot of reactive hydroxyl.This makes it be comparable with any other synthetic polymers.Therefore,it is a research focus to use cellulose as basic chemical materials and to develope environmental friendly and biodegradable materials.However,strong intra-and inter-molecular hydrogen-bond interaction exists between cellulose,which makes cellulose be insoluble in water and common organic solvents.At present,besides the traditional viscose process,the systems of dissolving cellulose include: copper ammonia solution systems,amine oxide systems,lithium chloride/dimethylacetamide system,ionic liquid,and so on.But problems such as cost,environment,recycle still exist in these systems.Recently,cellulose dissolution at low temperature has been paid attention due to friendly environment and convenient process.It is an important topic to discuss the coagulation method and preparation of composite materials based on the technique.This thesis investigates the method of coagulation and regeneration of dissolved cellulose,and studies the influence of small molecular EDTA on cellulose solutions,structure and properties of regenerating cellulose.The mechanism of sol-gel transition in the cellulose system has been clarified.Composite films have been prepared based on acetone-water coagulating bath,and their mechanical and thermostability,and the relationship of structure-property has been discussed.We expect to provide theory information on further utilization of cellulose and widen the application range of cellulose.The main study content is as follows:(1)To study the sol-gel transition in cellulose-EDTA aqueous solutions.It is found that EDTA can promote the sol-gel process of cellulose solutions.Temperature and concentration has influence on sol-gel transition,which has been investigated through a rheology approach.(2)Cellulose-EDTA composite films are prepared in a coagulation bath.The microstructure of the composite films and the interaction between cellulose and EDTA has been discussed.The mechanical properties and thermostability of the composite films has been detected.And the relationship between microstructure and mechanical properties is put forward.