Down fiber is the villus growing in the stomach of goose and duck. The surface of down fiber is a layer of membrane. Membrane layer is protein composing a major component of down fiber. Down fiber is densely covered thousands of tiny pores which change with the temperature to expansion and contraction. It has the temperature adjustment function and can absorb the flow of heat of human body sending out to isolate from the outside cold air invasion. Analysis from the volume testing, down fiber is higher than silk, cotton and heat preservation material. So down fiber simply as a heat preservation material, its economic value is much higher than other heat preservation material.

 

Scientists have studied the wettability, fluffy and stability of down fiber, but the study on the flame-retardant properties of down fiber is very little. With the continuous development of science and technology, countries around the world are increasingly demanding on the flame-retardant properties of textiles. Therefore, modification of down fiber flame-retardant is imperative. Sodium tungstate, potassium floutitanate and their mixed system has achieved good effect of improving the flame- retardant properties of down fiber. The experiment can be divided into the following steps: 

1. Firstly start the down fiber flame-retardant treatment: Take proper drying of down fiber to scatter in distilled water. Adding suitable amount of citric acid to adjust pH value, add flame retardant. Reaction should be in a certain temperature of water bath. After the reaction completed, wash, filter, and dry until fluffy.

2. Use the limit oxygen index apparatus to measure the scope of limit oxygen index.

3. According to thermo-gravimetric curve of thermal weightlessness rate and the fastest thermal weight loss rate to analyze thermal stability. The thermal degradation process of down fiber is divided into three stages: the first stage is the dehydration reaction of down fiber. The second stage is a series of pure chemical reaction. The third stage is exothermic process.

4. Using whiteness instrument to test the whiteness of down fiber to show and process the yellowing degree of down fiber.

 

Following conclusions can be drawn through experiments: From the thermo-gravimetric curve, sodium tungstate mainly reduces the second stage weightlessness and potassium floutitanate mainly reduces the third stage weightlessness. They can respectively reduce the fastest thermal weight loss rate to increase down fiber thermal stability. Rate of residual carbon increases and hinders its burning. Sodium tungstate and potassium floutitanate can improve the flame- retardant properties of down fiber of different levels, but their mixed system has a better flame-retardant effect.

There’s not big influence on surface structure and whiteness of the down fiber.