Study On Floss Silk Modified By Teos

Silk is regarded as the queen of fiber for its excellent quality and profound culture.Nowadays, as the living standard improves, more and more people attach importance toecological protection and health care. Thus due to having satisfied the consumptiondemand of the market, natural silk products, especially the floss silk products are verypopular with the consumers. However, the floss silk products are easy to entangle andadhere, or to be yellow over time, which makes a negative impact on the usage. Therefore,it is crucial to promote the performance and function by improving the productiontechnology, strengthening research abilities and increasing both intrinsic value andadditional values of the products, thus to enhance their market competitiveness.This issue compared the reaction mechanism and effect of different catalysts throughTEOS sol-gel method aiming at improving the compressive properties and warmthretention property of floss silk, followed by an exploration of the influence on weight gainof floss silk made by every process conditions, and finally summed up an optimizingmodified process via orthogonal experiment which made a combined effects on theexperimental factor levels. To further enhance the effect of modified floss silk by TEOSsol-gel method under the NH4OH catalysis, a micro-soluble pretreated could do in the first.Then, tested and analyzed the change of micro-morphology, aggregation structure andmechanical properties between floss silk and its modified one by scanning electronmicroscopy, fourier transform infrared spectroscopy and single fiber tensile strength tester.The results showed that:（1） It could improve the compressive properties and warmth retention property offloss silk and kept a good moisture adsorption/desorption performance of humidity by theTEOS sol-gel method modification. And selecting HCl as catalyst could have a bettereffect than NH4OH as a catalyst. In the former modification process, water consumptionleft a significant impact on the compression ratio and resilience compression ratio of flosssilk under the high humidity, the ultrasonic treatment time has a smaller influence, and the impact of the concentration of the HCl and alcohol is the smallest. The concentration ofHCl also can effect moisture adsorption/desorption performance of humidity seriously;（2） The reaction mechanism of modifying floss silk by TEOS sol-gel method underthe different catalysts was different. When the catalyst was HCl, the SiO₂hydrolyzed andpolymerized by TEOS was a three-dimensional network structure, and it coated on thesurface of the silk fibers as a film, with an obvious weight gain of the modified floss silk.When the catalyst was NH4OH, micro SiO₂was so granular and low in molecular weightthat it could fill into the microporous in silk under the ultrasonication;（3） After being modified by TEOS sol-gel method, some internal structures of thefloss silk fiber transformed from the random conformation to β-sheet conformation, andnew hydrogen bonds, covalent bonds formed among the silk molecules and the peptidechain. So the molecular structure became more close, the degree of molecular orientation,crystallinity, the strength and the initial modulus of fiber all increased, and the curve ofcreep and stress relaxation became moderate. The differences of these phenomena werequite obvious among different types of TEOS sol-gel process if the catalyst was NH4OH,and the increase of fiber strength and the initial modulus had a positive correlationrelationship with the increment of SiO₂. Therefore, increasing the amount of SiO₂on thesilk fiber when the catalyst was NH4OH could further improve the modification effect;（4） An appropriate micro-soluble pretreatment made before modifying floss silk byTEOS sol-gel method contributed to improving the modification effect under the NH4OHcatalysis, which was related to the increase of microporous number and size caused bymicro-soluble treatment.