| The characterization of blended textile fibers plays an important role in fiber production industry,trade,criminal investigation and archaeology.Traditional analytic techniques used for fiber identification such as sensory,microscopy,combustion,dissolution and infrared absorption spectroscopy,usually required extensive sample-pretrement and a lot of solvents.Therefore,it is necessary to establish a fast,accurate and simple operational method.In this thesis,a Pyrolysis-Gas Chromatography/Mass(Py-GC/MS)method was applied for qualitative and quanlitative analysis of two components blended fabrics.At first,a pyrolysis gas chromatography/Mass(Py-GC/MS)method was applied for analysis of polyester and cotton fibers as well as polyester/cotton blending ratio.In order to weigh sample accurately,the type of dispersant and the ratio of samples and dispersant were optimized.The fiber samples were milled into homogeneous powder in the precence of quartz sand.Then,a few microgram samples(samples:quartz sand =0.02 g:4 g)were carefully weighed and injected into pyrolysis gas chromatography.The optimal pyrolysis temperature 550 ? was obtained by Evolved Gas Analysis(EGA).The pyrograms of speciments were got at 550 ?,by which fibers could be identified.The characteristic peak of vinyl benzoate thermally decomposed from polyester was selected to determine the blending ratio of polyester/cotton and quantitative analysis was carried out by the linear relationship between the peak area and the mass of polyester.At the mass range from 0.025 to 0.25 mg of polyester,the achieved calibration curves exhibited good linearity with the correlation coefficient R2 higher than 0.999.Real samples with different polyester/wool blending ratios were measured and the relative standard deviation(RSD)(%)was less then 3%with threes repeated measurements.The deviation of result was less then 5%compared with the traditional method.The recovery(94.4%)of the methd was examined by baby puff.Secondly,a pyrolysis gas chromatography/Mass(Py-GC/MS)method was applied for analysis of polyester and wool fibers as well as polyester/wool blending ratio.Fibers could be identified by their Evolved gas analysis(EGA)curves and pyrograms.The characteristic peak of diphenyl thermally decomposed from polyester was selected to quantitatively determinate the blending ratio.The optimum ratio of samples and quartz sand was 0.02 g:4 g.At the mass range from 0.025 to 0.25 mg of polyester the achieved calibration curves exhibited good linearity with the correlation coefficient R2 higher than 0.995.Real samples with different polyester/wool blending ratios were measured and the relative standard deviation(RSD)(%)of polyester mass ratio in blended fibers was less then 3%with threes repeated measurements.The deviation of result was less then 5%compared with those obtained by the traditional method.Lastly,a pyrolysis gas chromatography(Py-GC)method was applied for analysis of polyester and acrylic fibers as well as polyester/acrylic blending ratio.Two characteristic peaks decomposed from polyester and acrylic were selected as quantitative peaks.Quantitative analysis was carried out according to the linear relationship between the peak area ratio of the two peaks selected above and the blending ratios.At the blending ratios range from 20:80 to 80:20 of polyester/acrylic blended fibers the achieved calibration curves exhibited good linearity with the correlation coefficient R2 higher than 0.979.Two real samples with different polyester/acrylic blending ratios were measured and the relative standard deviation(RSD)(%)were 3.82%and 3.13%with threes repeated measurements.The deviation of result was less then 17%compared with the dissolution method.Py-GC/MS method is simple,fast,accurate and suitable for the analysis of polyester/cotton fibers,polyester/wool fibers,polyester/acrylic fibers and their blending ratios.The proposed method can be used for quality control of blend levels in blended fiber yarns with two components. |
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