Study On Extraction Of Peanut Skin Dye And Its Application In Textiles

As an agricultural by-product,peanut skins are produced worldwide every year and are usually regarded as waste.This subject studied the dyeing properties and functional potential of peanut skin extracts as a natural dye to dye linen,wool,nylon fabrics,and the linen fabric,which was difficult to dye with natural dyes,was pretreated with chitosan to improve its dyeing performance and functionality.This topic is of great significance for waste utilization and the development of environmentally friendly natural dyes and their dyeing functional textiles.This topic uses ethanol aqueous solution as the solvent.The ethanol concentration,temperature and solid-liquid ratio were optimized,and the extraction parameters were obtained by analyzing the extraction rate and absorbance of the extraction liquid,and the extraction rate of peanut skin dye can reach 29.22%.A large number of polyphenols and flavonoids are present in peanut skin extract,and the peanut skin extract dyed on the fabric contains such components as catechin,quercetin,proanthocyanidin,tannin,rutin and so on by liquid mass spectrometry comparative database analysis.Fourier transform infrared spectroscopy（FTIR）was used to determine the groups in the extract,and thermogravimetric analyzer was used to determine the thermal stability of peanut skin extract.The functional test of peanut skin extract showed that it had good fluorescence properties and DPPH free radical scavenging ability.The peanut skin dye was used to treat the flax fabric by direct dyeing and pre-dyeing.In the selected process range,the fabric dyeing depth was the deepest under the following conditions:direct dyeing p H=7,temperature 120℃;Fe²⁺pre-dyeing p H=10,temperature110℃;Al³⁺pre-dyeing p H=5,temperature 120℃.The pretreatment conditions of chitosan were as follows:the dosage of chitosan was 5%,and the pretreatment temperature was 70℃.The dyeing process of chitosan pretreated dyed fabric was p H=3 and dyeing temperature 120℃.In terms of dyeing effect,dyeing p H value has a great influence on the hue of peanut skin dyed fabrics,while temperature has a great influence on the color depth of peanut skin dyed fabrics.Compared with direct dyeing,the K/S value of chitosan pretreatment was higher than that of direct dyeing at the same dye dosage and temperature,especially when the dyeing temperature was low.With the increase of temperature,the color depth between them gradually approached.Through the SEM,EDS and infrared tests,the chitosan was successfully finished on the fabric.and the chitosan,fabric and peanut skin were combined by ionic bond and hydrogen bond.The color fastness of the fabrics obtained by different dyeing methods was above grade3,and the pre-mordant dyeing and chitosan pretreatment could improve the color fastness of dyed flax fabric.The mechanical performance test shows that the high temperature（100-120℃）dyed linen fabric,with the increase of temperature,the breaking strength decreases slightly,and the breaking elongation increases.It was found that the thermal degradation process of chitosan pretreatment and dyeing linen fabric was similar to that of untreated linen fabric and its thermal stability was similar.Compared with KES of untreated and directly dyed flax fabric,it was found that the surface of the flax fabric dyed with chitosan pretreatment was rough,and the comprehensive feel effect was less,which was in the middle of the two.The functional effects of chitosan pretreatment and dyeing on the fabric were studied.It was proved that chitosan pretreatment and dyeing of linen fabric can effectively improve the UV protection and oxidation resistance of the fabric,but the fluorescence intensity decreased.It was found that the dyeing properties of fabrics such as wool and nylon were excellent,and the color fastness of the dyed fabrics was above grade 3.The UV protection and fluorescence properties of the dyed fabrics were greatly improved.This study shows that peanut skin dyes have a good dyeing effect on flax,wool and nylon fabrics,and chitosan pretreatment can effectively promote peanut skin dyes to dye linen fabrics.Peanut skin dyes and chitosan impart and improve the special characteristics of the fabric.This research has certain reference value for the application of peanut skin dyes in textiles.