Qualitative And Quantiative Analysis Of Silkworm Pupa Protein Viscose Fiber

Silkworm pupa protein viscose fiber, a kind of regenerated protein fiber getting the favor of people with its excellent physical performance, comfortable performance and environment friendly features, has a good market prospects. Currently, there is less research on qualitative and quantitative methods of silkworm pupa protein viscose fiber at home. So established the qualitative and quantitative method of the pupa protein viscose fiber is important to regulate the market and protect the consumer right.First of all, the qualitative identification characteristics of silkworm pupa protein viscose fiber were studied in this issue. Through the burning method, the combustion characteristics of silkworm pupa protein viscose fiber were similar with cellulose fiber. At the same time it showed weak combustion characteristics of protein; Through the microscope and scanning electron microscope, the vertical and horizontal cross section characteristics of silkworm pupa protein viscose fiber were nearly with viscose fiber,but cotton, linen, wool, polyester, polyamide and acrylic, etc. It was found that it was sensitive to acid and could be damaged by alkali by studying the dissolving properties of silkworm pupa protein viscose fiber in certain chemical reagent. The conventional methods, such as combustion, microscope and dissolve method, could be used for differentiating silkworm pupa protein fiber from cotton, linen, wool, polyester, polyamide and acrylic, etc. Through the nitrogen color reaction and protein content of the components of silkworm pupa protein viscose fiber, it was found that it contained nitrogen, as retaining the silkworm chrysalis protein components. The percentage of protein of silkworm pupa protein viscose was obtained. Through the infrared spectrogram analysis of the silkworm pupa protein viscose fiber, it was found that the silkworm pupa protein viscose fiber was composed of protein and fiber. There was absorption peak in the 1550 cm- 1 caused by amide groups- CO- NH – due to the existence of protein in the silkworm pupa protein viscose fiber. However the viscose fiber had not such characteristic which could be used to distinguish between silkworm pupa protein viscose fiber and viscose fiber in qualitative analysis. There were modified protein fibers such as soybean protein fiber and milk protein modified polyacrylonitrile fiber in the market, so the thermal properties of these three kinds of protein fibers were further studied, which could be used as auxiliary means for qualitative. By thermo gravimetric(TG) and differential thermal analysis, these three kinds of fibers exhibited different thermals which were conducive to fiber identification. Finally, the amino acid composition of silkworm pupa protein viscose fiber was studied by high performance liquid chromatography(HPLC). The result showed that it contained several kinds of amino acids necessary for the human body. Due to the kinds of amino acids indifferent protein containing a certain differences, this method could be used for qualitative analysis of protein fibers. At the same time, this method could be also used to identify counterfeit silkworm pupa protein viscose fiber by finishing. The qualitative method was finally established by a variety of methods of analysis and comparison.On the basis of qualitative analysis method which had been established, the chemical quantitative analysis methods were established when the silkworm pupa protein viscose fiber was blended with other fibers. When silkworm pupa protein viscose fiber was blended with polyester fiber or wool, 75% sulfuric acid method was used for quantitative analysis; When blended with cotton, ramie or flax, the formic acid /zinc chloride method was used; When blended with natural protein fibers such as wool or silk, the alkaline sodium hypochlorite method was used 80% formic acid and 20% hydrochloric acid method could be also used for quantitative analysis on the blended product of silkworm pupa protein viscose fiber and polyamide fiber; When blended with acrylic or spandex, dimethylformamide method was used; When blended with soybean protein fiber, sodium hypochlorite /hydrochloric acid method was used; When blended with milk protein modified polyacrylonitrile fiber, sodium hypochlorite/potassium thiocyanate method was used; While determining the quantitative analysis method, the correction coefficient of the residual fiber quality in the process were obtained. The quantitative analysis methods were accurate and reliable through a variety of verification tests of blended samples. However, due to the low level of protein in silkworm pupa protein viscose fiber, the accuracy of the quantitative analysis of 0.3 mol/L sodium hypochlorite solution needed to be further improved when the silkworm pupa protein viscose fiber was blended with viscose fiber.