Study On The Structure And Properties Of Cellulose-laponite Composite

Cellulose is one of the richest macromolecules in nature.It can be made into materials directly,and particularly processed into excellent products after dissolution.Cellulose owns regular molecular structure,and have plenty of reactive hydroxyl groups,which made cellulose an excellent polymer compared to other man-made ones.Therefore,cellulose can be regarded as a fundamental resource instead of a part of petroleum.Cellulose is eco-friendly and biodegradable,which made it be a hot study.However,cellulose is difficult to process in solution or as a melt because of its large proportion of intra-and inter-molecular hydrogen bonds,which brings about large difficulties for fabrication of fiber-,film-,and bulk-based cellulose materials by regeneration method.Therefore,a variety of systems have been exploited and found for dissolution of cellulose,such as Cuprammouium solution system,N,N-dimethylacetamide(DMAc)/LiCl,N-methylmorpholine N-oxide(NMMO)/water,ionic liquid and carbamate systems.However,there are many problems including cost,environment,and recycle.Recently,the dissolution of cellulose in pre-cooling NaOH/urea aqueous system has been paid attention.A certain concentration of NaOH/urea aqueous solution precooled below-10 oC can dissolve cellulose in five minutes,gaining a uniform and transparent cellulose solution.Based on the dissolution of cellulose,it has become an important topic to prepare high-powered cellulose materials.This thesis studied the composite of dissolved cellulose and laponite.The rheology of the cellulose hybrid solutions was clarified,and the behavior and mechanism of sol-gel transition affected by concentration and temperature were disclosed.Using a coagulation bath,cellulose-laponite composite films were prepared,which is characterized in structure and properties.These research results are expected to provide theoretical proof for preparation of high-powered regenerated cellulose materials.