Study On Grafting Of β-cyclodextrin Onto Cotton Fabric And Its Deodorizing Function

β-cyclodextrin (β-CD) , which has special cylinder-shaped hydrophobic cavity, can form inclusion with some appropriate molecules such as perfume, odors. As a result, the physical and chemical properties of these molecules were changed. In this paper, β-cyclodextrin was permanently grafted onto cotton fabric by chemical methods. The inclusive properties of β-CD were assigned to the grafted fabric. And the application of the fabric in deodorizing was studied carefully.Two kinds of chemical grafting methods-crosslinking by polycarboxylic acids, and binding onto cotton directly with monochlorotrazinyl-β-cyclodextrin (MCT-β-CD) -were investigated. The factors affecting the β-cyclodextrin content and the physical properties of the grafted fabric were researched. The optimal grafting process of the β-cyclodextrin onto cotton fabrics were formulated by rhombic experiment. Compared with the ungrafted fiber, some starchy cover on the surface of the grafted fiber can be observed obviously under scanning electron microscope. The grafted fabric had good wash fastness because it had low rate of weight loss after 10 times of rinsing.For the disadvantages of the two kinds of grafting process discussed above, CA-β-cyclodextrin (CA-β-CD) derivative was synthesized by indirected esterification and then grafted onto the cotton fabric. Two parts were included in the reaction. Firstly, the citric acid anhydride was synthesized. Secondly, CA-β-CD was prepared with the citric acid anhydride and p-cyclodextrin under the mild condition. The factors affecting the average degree of substitution of CA-β-CD were discussed. The optimal synthesizing process of CA-β-CD was formulated by rhombic experiment. Compared with the grafting process in which CA was used as crosslinking agents for grafting β-cyclodextrin onto cotton, the fabric grafted with CA-β-CD had high rate of grafting onto cotton and breaking strength.A new method for quantitatively measuring p-cyclodextrin on fabric was developed, based on the phenolphthalein indicator method which was normally used. β-cyclodextrin of the grafted fabric was hydrolyzed completely when the fabric was immersed in dilute alkali solution. Then the content of β-cyclodextrin in thehydrolytic solution was measured by spectroscopic method with phenolphthalein indicator. The improved method was more accurate than other normal methods because it can eliminate the influence of the fabric itself and other finishing agents on it.The CS-Chemoffice software was used to study the mechanism of forming inclusion between cyclodextrin and the guest molecular. The forming of inclusion was affected by space structure of cyclodextrin and the guest molecular, relevant acting force and reactive conditions.The volatility of perfumes was decreased because of the forming inclusion between perfume and P-cyclodextrin on the grafted fabric. So the fragrance on the fabric can last for a long time, and the deodorizing effect was enhanced. In addition, P-cyclodextrin can also absorb or adsorb some odor molecules. The double deodorizing functions of P-cyclodextrin make the deodorizing application in room wider.