(1) appearance: color because of different varieties of silkworm cocoon and raw silk, common are white and yellow. Pigment contains within the sericin, the come unglued after into white. Raw silk luster is soft, feel smooth, soft and elastic, mutual friction will produce a unique sound pleasing to the ear, called silk. (2) physical properties: the proportion of raw silk is 1.33 ~ 1.45, the specific gravity of 1.25 ~ 1.25 after degumming, similar to wool, cotton, linen small. Silk moisture absorption is strong, the standard return rate was 11%, the maximum moisture regain 36 ~ 39%, water quantity is 80 ~ 90% commonly, up to 101%, after degumming water quantity decreased. Raw silk length 1.3 ~ 1.6% after suction, cross sectional area increase by about 19%. Raw silk with good strength and elongation, 21 denier silk of the relative intensity of 3.4 ~ 4.3 g force/denier, elongation of 18 ~ 23%. Absolute strength and elongation decrease after silk scouring, raw silk moisture content increase the elongation increases with the strength reduced. Raw silk has good elasticity, torsional performance is good, but the plasticity after moisture absorption. Such as 21 denier GanSi raw silk is less than 15 g forces, elongation deformation can fully recover, and the wet silk by 5 gram force can produce plastic deformation. But better wearability of raw silk, silk 颣 section number less, sericin content, uneven distribution of sericin, smooth degree, poor combination between cocoon silk, closely will affect the wear resistance of raw silk. Raw silk has good heat resistance, short time heated to 110 ℃ quality without damage. Raw silk flammable, but burning slowly. Washing temperature of raw silk is 30 ~ 40 ℃. Raw silk also has good insulation, resistance with the increase of temperature, moisture regain and sericin content increase and decrease. Dry raw silk by friction with electrostatic, generally for a positive charge, the surface can be avoided by antistatic agent or increase the raw silk moisture regain. Raw silk light resistance is poor, easy embrittlement by sunlight yellow, intensity is reduced, the sun 200 hours, the strength loss of about 50%. (3) chemical properties: silk easy bibulous, usually dissolved sericin swelling, fibroin swelling only and does not dissolve in water. If the raw silk in the water boil for a long time, can cause mild hydrolysis, lose luster, damage the softness and feel, in pressure situations, 120 ℃ after 12 hours boil, fibroin will dissolve loss of 1/3180 ℃ dissolve all the. Raw silk to weak acid function stability, but in strong acid solution hydrolysis, when high temperature effect. Raw silk on the stability of weak alkali, under the influence of alkali hydrolysis significantly. With weak weak base of fibroin, but the concentrated solution can make fibroin hydrolysis, when high temperature effect is stronger. Raw silk does not dissolve in solvents, but soluble in copper ammonia solution and alkaline copper glycerol solution. Lithium, strontium, barium, calcium, zinc chloride, bromide, iodide, nitrate and sulfur content and salt solution of solvent and raw silk. Raw silk available direct dyes, acid dyes, basic dyes, reactive dyes, VAT dyes and various mordant dyes, but alkaline used protective agent. Raw silk can bleaching with reducing agent, oxidant, but antioxidant, especially chlorine oxidant damage silk.