Determination of blending ratio of Tencel/copper-ammonia blended product by UV-1800 spectrophotometry
Key words: spectrophotometry; US instrumentation ; UV-1100; UV-1800
![</p> Establish a spectrophotometric method for determining the blend ratio of Tencel/copper-ammonia blended products, ie, dissolve the Tencel, copper ammonia and Tencel/copper-ammonia blended products with 65% sulfuric acid, respectively, and measure the absorbance of the obtained solution. Value, according to the Lasbeli theorem to calculate the blending ratio of the blended product. The deviation between the test result and the actual ratio is -1.67%~1.80%, and the error is all within the tolerance range of the standard FZ/T01053-2007 "Textile fiber content mark", which is the quantification of TENCEL/copper-ammonia blended product. Analysis provides a method. Tencel and copper ammonia are regenerated cellulose fibers, which have the excellent characteristics of natural fibers and are favored by consumers. Various Tencel/copper-ammonia blended products have also been developed. Fiber quantification is an indispensable indicator for the processing of textiles in trade, trade and use. National regulations clearly require the identification of fiber content. Tencel and copper ammonia are very similar in appearance and chemical properties are very close. At present, there is no mature method for the identification of two kinds of fibers, especially the determination of the blending ratio of Tencel/copper-ammonia blended products is a technical problem. It has been suggested in the literature that the blending ratio of blended products can be determined by UV-visible spectrophotometry [1-3]. Therefore, the blending ratio of Tencel/copper-ammonia blended products was determined by UV-visible spectrophotometry. Explore the feasibility of this method. 2 Selection of test parameters 2.1 Selection of solvent Cellulose fiber can usually be dissolved by using formic acid/zinc chloride, sodium zincate, sulfuric acid or the like as a solvent [1-2]. The experimental results show that when using formic acid/zinc chloride and sodium zincate as solvents, the UV-visible absorption spectra of Tencel and Cu-Ammonia fibers are not much different, and when sulfuric acid is used as the solvent, the difference between the two is large, so the choice is Sulfuric acid is used as a solvent. The dissolution of cellulose by sulfuric acid is a continuous process, so its UV-visible absorption spectrum is less stable. Different concentrations of sulfuric acid have different solubility to cellulose. In this paper, the UV-visible absorption spectra of different concentrations of sulfuric acid were studied. It was found that the UV-visible absorption spectrum was stable with the decrease of sulfuric acid concentration. Increase in sex. When a 65% sulfuric acid solution is used, the UV-visible absorption spectrum is quite stable over a relatively long period of time. Therefore, 65% sulfuric acid was selected as a solvent for cellulose. 2.2 Pretreatment of the sample In order to ensure the stability of the absorbance value, the sample must be properly pretreated to loosen and remove non-fibrous materials. 2.3 Selection of water bath temperature and water bath time Cellulose fibers are simultaneously esterified and hydrolyzed in sulfuric acid, and cellulose is gradually hydrolyzed into smaller molecules until dissolved. In a relatively short period of time at room temperature, the hydrolyzate of cellulose tends to adhere more strongly to the surface of the fiber, causing only one layer of the fiber to dissolve. Oscillating heat treatment is usually necessary to completely dissolve the cellulose in sulfuric acid. At the same time, sulfuric acid is esterified with hydroxyl groups in cellulose, and the resulting hydrogen sulfate produces an ultraviolet absorption peak near 450 nm (the positions of the absorption peaks are slightly different for different kinds of cellulose fibers). It was found in the experiment that the intensity of the absorption peak near 450 nm rapidly increases as the temperature of the water bath increases. However, if the temperature is too high, the reaction is too intense and the absorbance of the solution is too large. Optimized, the final selected bath temperature was 70oC. It was also found in the experiment that after the water bath treatment for 30 minutes, the obtained solution was clear and transparent; when the treatment time was less than 30 min, suspended particles were present in some of the solutions, and the interference spectrum was determined. Therefore, the final choice of water bath treatment time is 30min 3 test 3.1 instrument and reagent UV-1800 UV-visible spectrophotometer"; SW22 digital constant temperature water bath oscillator; HG63 halogen moisture dryer. 65% sulfuric acid prepared by the laboratory itself. Silk G100 fiber is supplied by Lenzing Company (Austria) and copper ammonia fiber is supplied by Asahi Kasei Corporation (Japan) 3.2 Test conditions Ultra low speed scanning. Sampling interval: 0.1 nm, scanning wavelength range: 200~500 nm, slit width: 0.2 nm , source wavelength conversion wavelength: 300nm, absorption cell path length: 10mm. 3.3 Test method will be dried on a halogen moisture dryer to sample the sample placed in a 150mL grinding cone, add 50mL of 65% sulfuric acid, at 70 °C constant temperature water bath for 30min, then quickly cooled to room temperature with ice water mixture, immediately determine its UV-visible absorption spectrum. 4 Results and discussion Figure 1 is 65% sulfuric acid in the concentration of about 6mg / mL of Tencel G100 and copper ammonia A partial enlargement of the UV-visible absorption spectrum of the fiber, which all have an absorption peak near 450 nm, but the absorption peak position is slightly When the concentration is different, the peak position also changes slightly. The absorbance of these two absorption peaks is the largest at 444nm, and the difference is about 2 times. In this paper, the difference of absorbance is used to determine the Tencel G100/copper ammonia mixture according to Lasbeli's theorem. The blending ratio is therefore chosen to be 444 nm. Calculation of the 4.2a value In order to calculate the blending ratio of the unknown binary mixture, the a value of the mixture must first be determined. Considering the blending ratio of the usual binary blended product and the limitations of the method Sexuality, the binary mixture ratio designed in this paper is Tencel G100/copper ammonia=15/85~85/15, and a series of different proportions of Tencel G100/copper ammonia mixture are prepared to establish a training set, as shown in Table 2. Each sample was treated with 50 mL of 65% sulfuric acid, and the absorbance of the solution was measured at 444 nm. The absorbances of the solutions were calculated according to equations (4) and (5), and then calculated according to formula (2). The ai values ​​under the matching ratio are shown in Table 2. As can be seen from Table 2, the calculated ai value distribution range is narrow, ranging from 1.1095 to 1.2704, the average value is 1.2064, and the RSD is 3.38%. Can be used according to the equation ( 3) Calculate the blending ratio of the unknown ratio of Tencel G100/copper ammonia mixture. 4.3 Accuracy test This method is used to determine the known ratio of Tencel G100/copper ammonia binary mixture, according to the calculated day. The difference between the ratio of FM and the actual ratio FJ of silk G100 was used to judge the accuracy of the method. Weighing G100 fiber and copper ammonia fiber were respectively weighed, and a series of different proportions of Tencel G100/copper ammonia mixture were designed. After treatment with 50 mL of 65% sulfuric acid, the absorbance of the solution was measured at 444 nm, and the results are shown in Table 3. The absorbances of Tencel G100 and cuprammonium fibers at this concentration were calculated from the total concentration of the mixture and linear equations (4) and (5), respectively. Using the absorbance value, the ratio FM of the Tencel G100 is calculated according to the equation (3). Calculate the deviation of FM from the true ratio FJ. It can be seen from the data in Table 3 that the deviation between the analysis result and the actual ratio is -1.67 to 1.80. According to the FZ/T01053-2007 "Textile Fiber Content Marking", the textile composition analysis results should be within ± 5% tolerance. Therefore, spectrophotometry is used to quantitatively analyze the known ratio of the Tencel G/copper-ammonia two-component mixture, and the proportional errors of the actual measurement results are all within the standard tolerance range. 4.4 Precision Experiment This paper uses the percentage of the measured value FM and the actual ratio FJ as the basis for judging the precision of the method. In order to study the precision of the method, the proportions prepared in this paper are 30/70, 50/50, 70/30 respectively. Tencel G100/copper ammonia mixture, 9 parallel samples were determined for each ratio of mixture. The experimental results show that for the three ratios of Tencel G100/copper-ammonia mixture, the measured value and the actual ratio are very different, and the measured value is 96.13%~104.73% of the actual ratio, and the coefficient of variation is 3.06% and 2.39 respectively. % and 1.89%. It can be seen that the precision of the method is quite high. 5 Conclusion Tencel and copper ammonia fibers are very similar in appearance and chemical properties are quite close. At present, there is no mature method for the identification of these two fibers, especially the determination of the mixture ratio of Tencel/copper ammonia fiber mixture is a technology. problem. In this paper, we use the UV-visible absorption spectroscopy method to determine the Tencel G100/copper-ammonia mixture by using UV-visible absorption spectroscopy to establish the difference between the Tencel G100/copper-ammonia mixture. Spectrophotometry. The method uses 65% sulfuric acid to dissolve Tencel G100, copper ammonia and Tencel G100/copper ammonia mixture, and the ultraviolet-visible absorption spectrum of the obtained solution is measured. The a value of the Tencel G100/copper ammonia mixture was calculated. The a value and the absorbance value were used to calculate the blending ratio of the Tiansi G100/copper-ammonia blended product with unknown ratio, thereby solving the problem of quantitative analysis of the Tencel G100/copper-ammonia blended product. The accuracy and precision of the method meet the experimental requirements and have practical application significance. Keywords: spectrophotometry; US instrumentation ; UV-1100; UV-1800</p> </div> </div> <div class="tech-detail-share"> <!- - Baidu Button BEGIN --> <div class="bdsharebuttonbox"> <a href="#" class="bds_qzone" data-cmd="qzone" title="Share to QQ Space"></a> <a href ="#" class="bds_tsina" data-cmd="tsina" title="Share to Sina Weibo"></a> <a href="#" class="bds_weixin" data-cmd="weixin" title ="Share to WeChat"></a> <span>Share to:</span> </div> <script>window._bd_share_config = { "common": { "bdSnsKey": {}, "bdText": " ", "bdMini": "1", "bdMiniList": false, "bdPic": "", "bdStyle": "2", "bdSize": "16" }, "share": {} }; with ( Document) 0[(getElementsByTagName(](http://i.bosscdn.com/blog/nophoto.gif)
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