Ju Wei

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.

Simplified Model for Predicting Fabric Thermal Resistance According to its Microstructural Parameters

This paper presents a modified model to calculate the thermal resistance of woven and knitted fabrics according to the microstructural parameters. The model was established by analysing the heat transfer process in the simplified basic unit of the fabrics. The model was modified and checked by experimental values of various fabric samples. Pearson cor relation coefficients between the thermal resistance and fabric structural parameters were calculated. Results indicate that fabric thermal resistance can be predicted by the modified equation satisfactorily. The Pearson correlation coefficient from high to low follows such a sequence: fabric thickness, fabric volume density, fabric structural parameter a, fibre volume density, and fibre thermal conductivity.

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.

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).

Visualization Technology of Supercritical Fluid Dyeing

A visualization technology of supercritical CO2 dyeing and automatic control system was proposed, and 3D MAX software was developed to simulate kettle structure diagram for visualization in supercritical CO2 dyeing device. Meanwhile, the internal structure and function of the reactor were researched and supercritical CO2 fluid flow and the change process of the dye in the dyeing kettle and dye make-up kettle were analyzed. The staining mechanism of high temperature and pressure in the reactor was identified to provide a reference for visualization techniques of the supercritical CO2 dyeing.

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%.

Linear Regression Analysis on Dyeing of Feather Fibers with Acid Dyes

Feather fibers dyed with the weak acid dyes in ultrasonic conditions. Influence of different dyeing time and dyeing temperature on dye uptake and the formaldehyde content was discussed through the multiple linear regression analysis method, respectively. This paper discussed the correlation between dye uptake, the formaldehyde content and dyeing time, dyeing temperature, and established linear regression equation of dye uptake, the formaldehyde content with different dyeing process conditions, respectively. The best dyeing time was 45min and the best dyeing temperature was 80°C, according to the linear regression equation. The experimental results showed that dye uptake could achieve 92.1% and the highest value of the formaldehyde content was 33.09 mg/kg. The linear regression of dye uptake and the formaldehyde content had a high fitting precision and a good predicting ability, which can be of guiding significance to the actual production.

Study on the Supercritical CO2 Art of Dyeing

A new water-free dyeing process – Supercritical CO2 art of dyeing was proposed according to the high consumption of water and energy and serious environmental pollution problems. The results indicated that the effects of temperature, pressure and reaction time on dyeing deepness (K/S value) were investigated and the key factor is temperature. The PET fabrics dyed with disperse dyes in Supercritical CO2 were determined and the results showed that the dyeing protects with high dyeing rate and good characteristics, which can meet the requirements of the people on the dyed fabrics pattern and other visual art.