The Extraction Of Natural Plants' Antibacterial Components And Their Application To Silk

Natural plants were non-toxic and innoxious, with good decomposability and friendlyto the environment. The application had a long history, and the source was abundant. Mostof them were available to antimicrobial, diminish inflammation, detoxification, skin-care,anti-ultraviolet, etc.. Scutellaria baicalensis Georgi was selected from 15 plants in thepresent study as a kind of antibacterial agent applied to silk. The main Potent antibacterialagent owed to the presence of Baicalin, and the single factor influences of extractants werediscussed in the views of obtaining ratio and purity of Baicalin. The purified Baicalin wasanalyzed by the UV and TLC, and was tested if the Baicalin has antimicrobial activity bybacteriostatic-loop of filter paper. Pre-chelated the silk fabric with aluminium ion, and thenfinished by Baicalin, in the antibacterial finishing process. Whether dosages of Baicalinand aluminium ion, pH of finishing solution, temperature, time, different kinds ofpre-chelated metal ions, and solarization could make a difference on the antibacterial silkfabric against Bacillus subtilis, Escherichia coli and Staphylococcus aureus were discussedrespectively. After finished by the optimal process, some tests such as breaking strength,gas permeability were carried out on the silk fabrics, what's more, the structure andthermal stability of treated fabrics were determined through TG test and WAXD, etc..Finally, the dyeing kinetics and thermodynamics absorption model of Baicalin werediscussed on the silk fabric. The following results showed were based on the experiments:1,In the process of extracting, water extracting was better than alkali ion functionwater method, the optimal impurities removing of water extracting conditions were: pH 1,heat 30 min at about 70℃. Water extracting conditions were: extracted twice at about 100℃, the first time kept going on 40 minutes, the second cost 20 minutes, the quantity ofwater was about 8 times as that of Scutellaria baicalensis Georgi, the obtaining ratio andpurity of Baicalin were 8.5% and 86.9% respectively, moreover, the extractants andstandard sample had definite inhibited activity against Staphylococcus aureus,Escherichiacoli,Bacillus subtilis. The purified Baicalin had the same UV-spectrum as standard sample.2,The optimal conditions of antibacterial finishing carried out at the amount of KAlSO₄.12H₂O 5%owf, pH 4 approximately, finishing 20～40 minutes at 70℃. WhenBaicalin's concentration was at 0.5g/L, the inhibition ratios of Staphylococcus aureus,Escherichia coli,Bacillus subtilis were 85%～95%,92%～99%,95.35% respectively,UPF was over 34, after 25 times wash, the influence on Staphylococcus aureus was slim,the inhibit ratio amounted to 79.04%, UPF was more than 26, after 15 times wash, therewas no inhibited activity for Escherichia coli and Bacillus subtilis. According to AATCCTM 16-2003 method, After solarizing for 25 hours, the treated samples affirmed thatsolarization had no effect on inhibit activity against the three bacillus, and got a higheranti-ultraviolet performance.3,The Breaking strength and gas permeability of the finished silk were little declined.Thermal stability developed through TG. From the figures of WAXD of treated anduntreated fibers, it was shown that crystal structures of finished fabrics were hardlychanged.4,The kinetics process of Baicalin dyeing silk showed that, dyeing velocity and diffusecoefficient are both increased along with temperature, whether they were mordanted byaluminium or not. The equilibrium adsorption capacity of silk non-mordanted byaluminium decreased along with the temperature, which was opposite to the mordantedsamples, moreover, the equilibrium adsorption capacity of mordanted silk was 3 to 10times larger than that of non-mordanted.5,After simulating, regularity windage and simulation coefficient affirmed thatBaicalin's adsorption on silk was suit for Langmuir model, the dyeing process wasdecalescent, the dyeing heat A H was 2.3034 kJ/mol, the dyeing entropy A S was 6J/mol,the dyeing affinity and saturation absorption capacity increased as the temperatureincreased.