Gelatin, colorless to light yellow solid, in the form of powder, tablet or block. Glossy, odorless and tasteless. The molecular weight is about 50,000 ~ 100,000. The relative density is 1.3 ~ 1.4. Insoluble in water, but when immersed in water, it can absorb 5 ~ 10 times of water and swell and soften. If heated, it will dissolve into colloid, and then it will become gel after cooling to below 35 ~ 40ºC. If the aqueous solution is boiled for a long time, its properties will change due to its decomposition, and no gel will be formed after cooling. Insoluble in ethanol, ether and chloroform, soluble in hot water, glycerin, propylene glycol, acetic acid, salicylic acid, phthalic acid, urea, thiourea, thiocyanate and potassium bromide, etc. When the concentration of this product is below 5%, it does not coagulate, and it usually forms gel with 10% ~ 15% solution. The gelation temperature varies with concentration, coexisting salts and pH value. The viscosity and gel strength vary with the distribution of relative molecular weight, and are affected by pH, temperature and electrolyte. If the solution meets formaldehyde, it will become irreversible gel insoluble in water.
Complaint
