Surface Modification Of Nano Silica Sol And The Deepening Effects On Silk Fabrics

When the silk fabrics target dark color, reactive dyes are often selected in order to achievehigh color fastness. However, even if the dosage of dye is as high as6%(o.w.f.), the color depthcould not meet the requirements because of the poor permeability, while the color fastnessdecreases significantly and belows grade3. Considering this point, a novel deepening agentconsisting of nano silicon sol is designd, which is able to regulate light reflection and improvethe amount of light incident on the fibers. Then the color deepening properties of the agent andits effects on the wearability of silk fabric are investigated.SiNPs with varied diameters that are in the range between16nm and255nm are preparedfollowing St ber method. A deepening agent, namely MPS-SiNP, is prepared via modification ofsilica nanoparticle using a hydrophobic silane coupling agent (MPS,3-(Methacryloyloxy)propyltrimethoxysilan). Silk fabrics are finished with MPS-SiNP byimpregnation technology and technological parameter is investigated for deepening degree. As aresult of increasing dosage of MPS, reaction efficiency decreasing, the hydrophobic nature ofMPS-SiNP is enhanced and the particle size of the agent grows slightly. Deepening degree isreductive as the diameter increasing. The highest deepening efficiency is found for MPS-SiNPwith3.2%hydrophobic modification degree at pH=3. When the dosage is5%(o.w.f), deepeningdegree could be up to30%, enhancing with dosage of MPS-SiNP increasing. Deepening degreesis positively correlate with the adsorption capacity of MPS-SiNP onto the fabrics. The shade ofthe fabrics changes little after deepening finishing and capillary action was not deteriorated. Thewashing durability of the deepening effects is not long-lasting due to the absence of chemicallinkage between MPS-SiNP and fibers.Then, a reactive deepening agent was prepared, which contains sulfuricesterethylsulfonylgroups on the particle surface. The preparation technology, as well as its reactivity, isinvestigated. The observation of a high soaping fastness of the finished fabrics demonstrated theformation of chemical bonds between PAFSES-MPS-SiNP and fibers. The fastness could befurther improved with the increase in the density of sulfuricesterethylsulfonyl on the surface ofPAFSES-MPS-SiNP. Deepening degree reached36%when the sulfuricesterethylsulfonyldensity is7.1×10-3per square nanometers, dosage is5%(o.w.f.) at pH value is3and it could stillremain30%after soaping5times. The deepening agent is more efficient when it is engaged indeep-color fabric deepening finishing. The shade and breaking strength have little changed, whereas capillary action is slightly higher. After soft finishing, the style of finished fabric isclosed to original fabric.