Surface Modification Of Silk Fabric By Solid-State UV Laser

The irradiation of UV laser is one of physical methods for surface modification of polymers, which is friendly to the environment.The thesis was aimed to study the surface morphology and physical & chemical properties of silk irradiated by UV laser with a wavelength of 266nm.The dyeing property of the irradiated silk fabric was also studied.Scanning electron microscope（SEM） observation revealed the morphological modification of the silk fiber irradiated by UV laser with the formation of ripple and pore structure.XPS results showed that the N/C ratio of the irradiated silk fabric decreased,while the O/C ratio increased.In addition,the number carboxyl on laser treated fabric surface increased.Whiteness,tensile strength of the irradiated silk fabric decreased adversely.The properties of whiteness and tensile strength were related with laser parameters including laser power,pulse frequency,space between filling lines,valid vector step size,and time delay between valid vector steps etc.The influence of Na₂SO₄ concentration,Na₂CO₃ concentration,dyeing temperature and dyestuff amount on the dyeing properties of laser-irradiated silk fabric dyed with medium-energy reactive dye were studied respectively.The results revealed the Na₂CO₃ concentration,which was most suitable for dyeing,was not changed due to laser treatment.To obtain the same dyeing shade, dyeing of laser-treated silk fabric could save about 10-40g/L of sodium sulfate,according to the type of dye.The laser-treated silk fabric could be dyed with medium-energy reactive dye at the temperature of 40- 50℃,which is 10-20℃lower than normal temperature.What was more,to get the same K/S value,dyeing of the laser-treated silk could save the amount of dyestuff 0.5-1%（o.w.f）.The dye uptake of laser-treated silk fabric was improved,that is,to achieve the same dye uptake,the time required for laser-treated silk fabric was shortened.Compared with color fastness of the untreated silk fabric,color fastness to washing of the UV laser-irradiated silk fabric dyed with reactive dyestuff changed little,while color fastness to rubbing reduced.When dyeing temperature dropped from 60℃to 45℃.compared with color fastness of the untreated silk fabric dyed at normal temperature,the color fastness to washing of the UV laser-irradiated silk fabric dyed with reactive dyestuff was invariable,while the color fastness to rubbing declined a little.To solve this problem,further research needs to be done.