Preparation And Characterization Of Nano Titanium Dioxide/Ramie Fiber Functional Composite Materials

Ramie, also called China Grass, has been grown in China for manycenturies. Ramie fiber is a nascent bast fiber and has the characteristic of high Young'smodulus, high degree of polymerization, high intensity of single fiber and so on.Therefore, it bears the advantages of the cool, stiff and neat, high air pervious, moistureabsorptive, antimildew, good antibacterial and mothproof properties etc. Ramie fiber,which is widely regarded as the king of natural fiber, is one of the age-old and gracefultextile materials and is suitable for weaving many kinds of healthy products with theexcellent wearability. Ramie textile has the natural style and accords with thepsychology of the regressing nature. Therefore, ramie textile is received more and morefavors in recent years. In our country, the ramie production about 90% has beenexported to the western countries. At present, the global carbon dioxide emissionincreases sharply and the ozonosphere in air becomes more and more slightly rarefied asthe industrialization process accelerates. These results in the increase of solar ultravioletintensity year after year, as a result, the amount of people suffered from various skindiseases increased awfully. Moreover, environment deterioration, climate warming andair pollution lead to the increase of bacterial propagation and infectious diseases.Therefore, great attentions have been paid to the ultraviolet rays protection in recentyears and how to solve ultraviolet rays harm has been turned into a most urgent problem.Then, developing and preparing functional materials and textiles with good antibacterialand mothproof properties is an effectual solution to above problems. The furtherfunctional exploitation and utilization of the ramie fiber was received more and moreattention in recent years due to the decrease of the reserves of energy and resource andthe increase of the attention and recognition of the environment problems.So it can be expected to obtain better materials with high antibacterial andantibacterial performance from the ramie fiber and titanium dioxide. In this thesis, ourresearch is mainly focused on the following three parts:1. A highly dispersed nanocrystalline rutile powder (NRP) having ultrafine andnarrow distributed diameters was successfully prepared via an improved conventionalliquid one-step method with introducing dioctyl sulfosuccinate sodium salt (AOT)surfactant in the reaction anaphase. The average grain size of the product is 10-20 nm. The effects of titanium tetrabutoxide (Ti(OBu)₄) to ethanol volumetric ratio,precipitation temperature, peptization temperature and presence of dioctylsulfosuccinate sodium salt (AOT) on the properties of NRP were studied. A newprocedure for synthesizing NRP is proposed, and the optimum conditions for preparingNRP were obtained. The TEM, XRD, SEM and FT-IR results were also investigated inthis work. The optimum conditions for preparing nano rutile titania crystals arevolumetric ratio of Ti(OBu)₄ to ethanol of 1:4, the precipitation temperature of 20℃,the peptization temperature of 90℃, and a small quantity of AOT added in the reactionanaphase.The improved liquid one-step method not only has many excellent characters, such assimple process, low reaction temperature, non-strict requirement to the technology andequipment, less energy consumption, but also resolves the problem of dispersivity ofnano particles readily. The NRP with highly dispersed and narrow distributed diametersis obtained.2. A nano titanium dioxide/ ramie fiber multifunctional composite materials wassuccessfully prepared by the manner of physical adsorption. The SEM and UV-Visresults were also investigated in this work. The composite materials bear high anti-ultraviolet and antibacterial performance with a wider range absorbing ultravioletradiation of 410 nm. The procedure has many excellent characters, such as simpleprocess, less energy consumption and pollution and easy to industrialization.3. A nano titanium dioxide/ramie fiber multifunctional composite material combinedwith chemical bonds was successfully synthesized via modification of carboxymethylreaction of ramie fiber. The influencing factors of preparing carboxymethyl cellulosewere investigated in detail. The optimum conditions for preparing carboxymethylcellulose were obtained. The multifunctional composite materials were prepared by theslow hydrolysis reaction of the carboxymethyl cellulose and the titanium tetrabutoxide.According to the studies, the composite materials bear high antiultraviolet andantibacterial performance. The effects of the titanium tetrabutoxide (Ti(OBu)₄)concentration, the moisture content and the degree of substitution of the carboxymethylcellulose were studied. The new composite materials have many advantages, such ashighly dispersity, large content, narrow distributed diameters and firm active force withramie fiber. Many advantages, such as small content and weak active force with ramiefiber can be solved by this procedure. Furthermore, this new method provides a new mode and groundwork of the functional composite materials preparation by the mannerof chemical bond.