The Preparation And Modification Of Cellulose Aerogel Porous Materials

As cellulose is a natural existing renewable resource with the highest content, billion tons of cellulose could be manufactured from plant photosynthesis worldwide each year. It is a degradable polymer compound material with excellent performance in application and synthesis. It could also be decomposed into low molecular compounds in a short period of time through actions of microorganisms if expired. As for increasingly shortage of resources such as petroleum & coal and pollution of chemical raw materials in today’s world, it has very important long-term significance to produce with cellulose as raw material instead of traditional chemical raw materials under the complicated situation. In recent years, cellulose aerogel materials with structural characteristics such as high permeable & nano porous three-dimensional network structure, high porosity, low density and high specific surface area have shown significant function in fields such as optoelectronics, sensors and bio-medicine.In this thesis, we chosed different dissolution systems of cellulose based on sol-gel process of cellulose, prepared natural cellulose aerogel film materials and had corresponding modification and application. The main contents are as follows:Using NaOH/urea/water solvent system to form natural cellulose aerogel porous material (referred to as CAPM), and verified that it had formed aerogel film with three-dimensional network structure, high porosity, low density and high specific surface area through detection means such as SEM, FT-IR, XRD and BET. Meanwhile, results showed that the excellent thermal insulation and acoustic property of cellulose aerogel could play a role in fields such as military and medical treatment through analysis of mechanical property, thermal insulation, acoustic property, moisture transfer performance and thermal behavior. The study also found performance shortcoming of aerogel film, and confirmed that improving mechanical and flame retardant properties may be set as direction of structural optimization in future research.Cellulose-PANI material reported in previous literature of selection dissolved cellulose in traditional non acid system or prepared in heterogeneous system, while the paper selected phosphoric acid/poly phosphoric acid solvent to prepare cellulose-PANI conductive composites in liquid crystal system. Adopted H3PO4 and HCl respectively as dopant to dissolve aniline and form aniline salt ions, and tested the prepared composites with polarizing microscope, rotational rheometer, SEM, XRD, FT-IR, and conductivity characterization respectively. Test results showed that the solution in phosphoric acid/poly phosphoric acid system exhibited rainbow color caused by birefringence, which confirmed the formation of cellulose liquid crystal solution; in this solvent system, H3PO4 was a better dopant compared with HCl; cellulose-PANI doped with H3PO4 had higher conductivity, and the electrical conductivity was the best when ratio of aniline and cellulose was 2:1.Adopted cellulose to encapsulate essential oil of jasmine through epoxidation supporting of P-CD, prepared functional materials with substained release, and extended application of cellulose. Selected NaOH/urea/water solvent system to dissolve cellulose, cellulose crosslinked with crosslinking agent ECH in low-temperature alkaline environment, and supported β-CD on cellulose fiber after activation. The prepared cellulose/β-CD had good inclusion property and provided an effective way for development of functional fiber. In the experiment, set multi groups of different amount of P-CD in cellulose solution for comparison, measured sustained-release effect of materials prepared with different concentrations of P-CD, and determined the most appropriate reaction mass ratio of P-CD and cellulose. The material was verified to have sustained release function through FT-IR, SEM, XRD test and performance test of inclusion property and sustained release. As the main component of jasmine essential oil is linalool, it can be applied for clothing materials which have certain repellent effect for mosquito.