Lai Jiu Zheng

Study on Dyeing of the Plasma Modification Silk Fabric in Supercritical Carbon Dioxide

A study has been conducted into the dyeing of silk fabric in supercritical carbon dioxide. In order to reach better dyeing effect, plasma modifying is used to silk. Plasma modifying can decompose disulfide bond of the protein fiber, change the state of scale layer and break silk gum of fiber so that dyestuff could infiltrate. Factors of plasma modifying are fixed, including pH value, processing time. And they affect the values of fabric colour feature and fabric strength. In this work, C.I. Disperse Blue-77 and C.I. Disperse Yellow E-3G are used by combining orthogonal experiment and single factor analysis. During dyeing process, temperature and pressure have a great impact on the result. Modification process and dyeing process are optimized, and the best process is determined. The results presented in this study show dyestuff can infiltrate through modified fabric easily. Through the testing, the washing fastness and rubbing fastness of silk fabric after being modified are improved. The changes between before and after dyeing are analyzed by scanning electron microscope and infrared spectrometer. It is showed that modified fabric obtains a better effect.

Extraction and Characterization of Silk Fibroin from Waste Silk

Waste silk fibers were dissolved in calcium chloride aqueous solution. Effect of calcium chloride concentration on silk solubility was studied. Dialysis method was used to purify the dissolved silk fibroin. The purified silk fibroin was characterized by FTIR and thermoanalysis technique. Results showed that the purified silk fibroin mainly had irregular curly conformation. The glass transition temperature of the regenerated silk fibroin reached 90.6°C-135°C, higher than 78.9°C-135°C before purification. Thermal weight loss temperature by 50% was 490.3°C differing from 429.7°C before purification.

Preparation and Characterization of Regenerated Wool Protein PAN Blended Fibers

Wasted wool fibers were dissolved by reductive method. The dissolved wool protein was extracted by the membrane technology and blended with the Polyacrylonitrile (PAN) polymer to prepare regenerated fiber. Effects of pH value and dissolution assisting agent type on dissolution percentage of the wasted wool fibers in sodium pyrosulfite reductive system were investigated. Effects of the drawing times on properties of the fibers were also studied. Results indicated that the dissolution percentage rose with the increase of pH value of the reductive solution. Metallic salts have better dissolution assisting effect than urea. Breakage percentage of the as-spun fiber and tenacity of the regenerated protein fiber rose with the increase of the drawing times.

Electrospinning of Pullulan Nanofibers for Food Package Materials

Electrospinning is a process that fabricates continuous fibers with diameters in the nanoto micron range. Pullulan with different concentrations were successfully electrospun into nanofibers with water as solvent in this study. We have evaluated the effects of solution concentration on the morphology of the fibers. The morphologies of the nanofibrous mats were examined by Scanning Electron Microscopy (SEM). With increasing the solution concentration, the electrospun nanofibers changed from beaded nanofibers to smooth nanofibers, meanwhile, the average diameters of electrospun pullulan nanofibers increased from 44nm, 89nm, 136nm, 172nm to 219nm when the solution concentration changed from 12, 15, 20, 25 to 30 wt%. The distribution of electrospun fibers is normal distribution. The electrospun nanofibrous mats will be a promising food package material.

The Dyeing Research of Wool Fibers Based on Reactive Disperse Dyes in Supercritical Carbon Dioxide

This paper adopts reactive disperse bright-red KR-2B to dye wool skeins in supercritical CO2 dyeing equipment. The influencing factors are analyzed by measuring the surface depth of dyed wool skeins, including time, temperature and pressure, and the optimal dyeing parameters are as following: time 60min, temperature 120°C, pressure 24 MPa. Then we adopt the scanning electron microscope (SEM) and the infrared spectrum (FTIR) to observe the apparent shape and structure before dyeing and after dyeing. The results indicate that the global dye structure divide and the dyestuffs have good fixation on the wool skeins.

Supercritical CO2 Anhydrous Dyeing Equipment and the Static Stress Analysis of Key Components

In anhydrous dyeing research process, a set of self-developed supercritical CO2 fluid dyeing equipment was manufactured. With computer control system, temperature and pressure was controlled accurately in dyeing process. As key components of the supercritical dyeing equipment, the coloring matter kettle and the segregator had a close relationship with the dyeing process. The finite element analysis software ANSYS was used to analyze the static stress of supercritical dyeing equipment. The model of the coloring matter kettle and the segregator were established, and the static stress analysis result of the coloring matter kettle and the segregator were obtained. These models not only confirmed the safety of the dyeing equipment, but also offered related parameters and provided the methods for improving the efficiency of dyeing equipment design.

Study on Alizarin Dyes on Polyester-Cotton Knitted Fabrics Dyeing in Supercritical CO2

Using natural alizarin dyes to dye polyester - cotton65/35 knitted fabric in supercritical CO2 dyeing equipment, and analysis the influencing parameters including dyeing temperature, time and pressure. The parameters are optimized as following: dyeing temperature 115.21°C, dyeing time 71.42 min and dyeing pressure 26.22 Mpa. Adopting alizarin dyes to dye polyester-cotton65/35 knitted fabrics in supercritical CO2 could obtain a good dyeing effect, and the color fastness to rubbing and color fastness to washing of dyed fabrics meet The National Standard (GB18401-2003).

Supercritical CO2 Dyeing on Wool Hank

Reactive disperse blue R was adopted for supercritical CO2 dyeing on modified wool hank by protease in self-made supercritical CO2 dyeing device. The optimal process of dyeing was optimized by Box-Behnken Design experiment as following: dyeing temperature 103.60°C, dyeing pressure 24.23 MPa and dyeing time 62.03 min. Compared with the unmodified wool hank, the rubbing fastness and the washing fastness of modified wool hank by protease were better, and its color fastness met The National Standard (GB18401-2003).

Influences of Coagulation Bath on Properties of Thermal Regulating PAN Fibers

Physical properties of thermal regulating polyacrylonitrile (PAN) fibers prepared at different concentration of coagulation bath were tested to investigate influences of coagulation bath on properties of the fibers. Results indicated that linear density of the fibers increased, breaking strength, thermal shrinkage and boil water shrinkage decreased while elongation first increased and then decreased with the increasing of mass fraction of sodium thiocyanate (NaSCN) in coagulation bath. The optimum NaSCN concentration in coagulation bath should be 10%. Fibers prepared under the above NaSCN concentration showed good mechanical and thermal properties, and the breaking strength was 1.35 cN/dtex, the enthalpy was 26.0 J/g and the thermal efficiency was 78.4%.

Mixed Reactive Disperse Dyes on Wool Yarn Dyeing in Supercritical CO2

Mixed reactive disperse dyes is adopted to dye wool yarn by supercritical CO2 dyeing equipment, and the influencing factors on the wool yarn uptake are analyzed including dyeing temperature, dyeing time, dyeing pressure. The results reveal the interaction relationship between single dyes dyeing on the wool yarn: the total uptake of mixed reactive disperse dyes and the uptake of single reactive disperse dyes increase with the increasing of temperature and pressure, it also increase by the extension of time. In the same conditions, the total uptake of mixed reactive disperse dyes is more than the uptake of single reactive disperse dyes. The uptake of single reactive disperse dyes in the mixed dyes is less than the uptake of single reactive disperse dyes. In the dyeing process of mixed dyes, the wool yarn dyeing of two dyes has selective and competitive. Both color fastness to rubbing and color fastness to washing of dyed wool yarn are in line with national institute of standards.