50mL of hydroxypropyl methyl fiber, remove the condensate tube from the separation column, rinse with water, wash and add 3 drops of phenolphthalic indicator liquid into the collection liquid, titrate to pH 6.9 ~ 7.1 (measured with an acidity meter), write down the volume V1 (mL) consumed, and then add 0.5 g of sodium bicarbonate and 10 mL of dilute sulfuric acid, let stand until carbon dioxide is no longer produced, iodized Potassium 1.0 g, dense, shake well, set Leave in the dark for 5 minutes, add 1mL of starch indicator, titrate to the end point with sodium thiosulfate titrator (0.02mol/L), and write down the volume V2 (mL) consumed. In another blank test, the volumes Va and Vb (mL) of the sodium hydroxide titrant (0.02 mol/L) and the sodium thiosulfate titration (0.02 mol/L) consumed were recorded respectively. Calculate the hydroxypropoxy content. Note: “Precision Weighing” means that the weight taken should be accurate to one thousandth of the weight being weighed. 10 Safety 0202 Health hazards: This product is safe and non-toxic, can be used as a food additive, no heat, and no irritation to skin and mucous membranes. Generally considered safe (FDA1985), the allowable daily intake is 25mg/kg (FAO/WHO 1985), and protective equipment should be worn during operation. Environmental impact: Avoid air pollution caused by dust flying by random dusting. Physical and chemical hazards: Avoid contact with fire sources. Avoid forming a large amount of dust in a confined environment to prevent explosive hazards. Storage matters: Pay attention to sunscreen, rain and moisture protection, avoid direct sunlight, and store in a dry place. Safety term S24/25Avoid contact with skin and eyes. Avoid contact with skin and eyes. Ceramics manufacturing uses: It is widely used as an adhesive in the production of ceramic products. Plastics: used as molding release agents, softeners, lubricants, etc.