Applicstions Of β-Cyclodextrin In Textile Finishing

Cyclodextrins (CDs), which are cyclic oligosaccharides having more than six glucose units linked byα-(1,4)-glycosidic bonds. CDs can be obtained through the enzymatic degradation of starch by Bacillus maceran. Their toroidal shape and the presence of internal hydrophobic hollow cavity produce the extraordinary capability to include a wide variety of different molecules which fit into their cone-shaped hydrophobic cavity and to form stable inclusion compounds. According to the number of glucose units in the CD ring, we distinguishα-CD,β-CD andγ-CD, which contians six, seven, and eight glucopyranose units, respectively.β-CD is commercially most interesting because of its simple production, availability, cavity diameter, and price.β-CD and its derivatives are successfully exploited in different fields, such as food manufacturing, cosmetics, pharmaceuticals, and analytical and organic chemistry. In recent years, thanks to its benign toxicological and ecological properties,β-CD has become important as auxiliaies for textile finishing.In this paperβ-CD was fixed on the fabric by three methods, namely cross-linking grafting, sol-gel and chemical modification. It can bring some special factions to fabrics shch as fragrance, antibacterial and uvioresistant properties. Glyoxal and citric acid (CA) were used as cross linking agents. The nano-TiO2 and nano-ZnO sol were studied in the sol-gel method.β-CD was modified by sulfonation, carboxymethylation and prepolymerization. Contents and conclusions of the studies are mainly as follows.β-CD was grafted onto cotton fabric using 30% of glyoxal solution as a cross-linking agent by pad-dry-cure and cold pad-batch process. The effects of glyoxal,β-CD, catalyst dosage, curing temperature on the grafting yield ofβ-CD were studied. The optimum pad-dry-cure process was determined by orthogonal experiments: 70g/L ofβ-CD,50g/L of glyoxal,2g/L of CA and cured at 140℃for 3min. The results showed that the fragrance inclusion and reservation property of grafted cotton fabric was improved, the wrinkle recovery angle was markedly increased, the breaking strength retention was over 75%, and the whiteness was slightly decreased. The optimum cold pad-batch process was determined by orthogonal experiments:35g/L ofβ-CD,15g/L of glyoxal,17g/L MgCI2·6H2O,2g/L of CA. Compared the pad-dry-cure process with cold pad-batch process, It was found that the fabric treated by pad-dry-cure process had higher content of fragrance and wrinkle recovery angle, lower whiteness. In cold pad-batch process less dosage of glyoxal andβ-CD were used to treat the fabric, It can save energy.(3-CD was grafted onto wool and silk fabric using CA as a cross-linking agent and sodium hypophosphite (SHP) as a catalyst by pad-dry-cure process. The effects of the concentration of (3-CD, CA, and SHP, cured temperature and time on the properties of finished fabric were studied. The difference of wool and silk in treating process and property was found. The optimum conditions for silk were as follows:β-CD 80g/L, CA 80g/L, SHP 40g/L, cured at 160℃for 2min. The results indicated that the addition of (3-CD can increase weight gain of fabrics and improve the ability to include fragrance markedly. The wrinkle recovery angle, whiteness and breaking strength were also improved slightly. The optimum conditions for wool were as follows:β-CD 80g/L, CA 80g/L, cured at 160℃for 3min. The results indicated that the addition ofβ-CD can increase weight gain of fabrics and improve the ability to include fragrance markedly. The whiteness was also improved slightly, but the wrinkle recovery angle and breaking strength were slightly decreased.Nano-TiO2 and nano-ZnO sol solution were prepared with Ti(OC4H9)4 and Zn(Ac)2·2H2O as raw material, respectively. Nano-TiO2/β-CD nano-ZnO andβ-CD were loaded on the cotton fabrics by sol-gel method. The properties of treated fabrics were studied. The optimum synthesis process of Nano-TiO2 sol was established as the molar ratio of Ti(OC4H9)4:HN(CH2CH2OH)2 CH3CH2OH:H2O was 1:0.8:20:0.6, reacted 80℃for 1h and then reflux reacted for another 1h. The average particle size of the sol was 14.3 nm. The optimum synthesis process of Nano-ZnO sol was established as the molar ratio of Zn(Ac)2·2H2O:HN(CH2CH2OH)2:NaOH:C2H5OH was 1:1.5:1:114, reacted at 80℃for 45min. The average particle size of the sol was 73.7nm.β-CD was added into the sol, and cotton fabric treaded with the sol by pad-dry-cure technique. Based on the tests of anti-UV, photocatalysis, antibacterial and weight gain rate after adsorbing essence, the results showed that the treated cotton fabrics added withβ-CD had better adsorbability to essence, anti-bacterial activity, photocatalytic degradation to formaldehyde and excellent anti-UV property. However, the fixation fastness of the nano-ZnO sol on the fabric was bad, it can be improved by adding the adhesives.The inclusion complexes of benzoic acid withβ-CD and vanillin withβ-CD were prepared by the coprecipitation method. The effects of the molar ratio of guest compound to host compound, dosage of solvent, inclusion temperature and time on the properties of inclusion complexes were studied. The inclusion complex was grafted onto cotton fabric by CA as a cross-linking agent and SHP as a catalyst. The optimum inclusion-forming condition of vanillin withβ-CD was established as the molar ratio ofβ-CD to vanillin was 1:1, with the inclusion temperature at 50℃for 2h. The optimum grafting process of vanillin inclusion complex was CA 80 g/L, the inclusion complex 60 g/L, SHP 40g/L, cured at 160℃for 3min. The optimum inclusion-forming condition of benzoic acid withβ-cyclodextrin was established as the molar ratio ofβ-CD to benzoic acid was 1:2, the volume ratio of water to absolute ethanol was 80:20, with the inclusion temperature at 50℃for 2h. The optimum grafting process of benzoic acid inclusion complex was CA 80 g/L, the inclusion complex 60 g/L, SHP 40g/L, cured at 160℃for 4min. The inclusion ratio ofβ-CD to benzoic acid was higher than that to vanillin because of the difference on their molecular structure.The sulfonated and carboxymethylβ-CD derivatives were prepared with concentrated sulphuric acid and monochloroacetic acid, respectively. They could form ionic bonds directly with wool and silk fabric without adding cross-linking agent. Their applications in perfume finishing on wool and silk fabrics were discussed. The results indicated that fabrics finished withβ-CD derivatives could include more perfume and release it slowly, and fabrics finished with perfume complexes ofβ-CD derivatives had more perfume than that finished with P-CD derivatives. However, the fixation fastness needs to be raised.In order to improved the grafting rate ofβ-CD on cotton fabric, solubleβ-CD prepolymer (β-CDP) which was prepared with epichlorohydrin as cross-linking agent in an alkaline medium was grafted onto cotton fiber using CA as a cross-linking agent and SHP as a catalysts by the pad-dry-cure technique. The effects of the concentration of CA,β-CDP and SHP, curing temperature and time on the properties of finished fabric were studied. The optimum grafting conditions were as follows:β-CDP 30g/L, CA 50g/L, SHP 30g/L, cured at 180℃for 2.5min. The results showed thatβ-CDP kept the ability ofβ-CD to inclusion, slow release and had good mechanical strength, stability and chemical adjustable. The property of the fabric grafted with P-CDP was better than that withβ-CD. The P-CDP grafted fabric has improved fragrance absorption and controlled release ability, with whiteness, breaking strength and wrinkle recovery angle enhanced slightly.In order to impart multifunctions to cotton fabric,β-CD and chitosan (CTS) were finished on cotton fabric. The results indicated that the maximum adsorption of finished fabrics was obtained when the dosage of CTS was 2g/L andβ-CD was 30g/L. The fabric finished with chitosan of higher molecular weights had better adsorption ability and lower antibiotic activity. The adsorption of washed fabric could be improved by using cross-linking agent. In order to improve the properties of the finished fabric, chitosan grafted withβ-CD (CD-CTS) was prepared, which was applied to the durable press finishing of cotton fabric finished with CA as a crosslinker and SHP as a catalyst. The results showed that the effect of treatment of CD-CTS was superior to that of CTS and CTS blended withβ-CD. The optimum process was determined by orthogonal experiments as follows:CA 80g/L, SHP 50g/L, CD-CTS 3g/L, cured at 180℃for 3 min. The wrinkle recovery angle of finished fabric increased by 105°, the store perfume properties increased to over 2.5 times. The finished fabric had the inhibition to Staphylococcus aureus and Escherichia coli and its breaking strength and whiteness were also improved.It is summarized that the fabrics grafted withβ-CD have wide perspective and practicability on the development of multfunctional fabrics.