ASTM D5400-15(R2021) pdf free download

ASTM D5400-15(R2021) pdf free download.Standard Test Methods for Hydroxypropylcellulose
31. Significance and Use
31.1 This test method determines the amount of substituent groups added to the cellulose backbone. The level can affect solution properties, rheology, solubility parameters, and film properties. 31.2 Gas chromatographic procedures involving cleavage of side groups with hydriodic acid (see Test Method D3876) are not applicable for highly substituted hydroxypropylcellulose because the amount of hydriodic acid and the temperature required to achieve complete reaction lead to side reactions that render the method non-quantitative.
32. Apparatus
32.1 Chromic Acid Oxidation Apparatus, as illustrated in Fig. 3. The inlet for nitrogen and water in the reaction flask is a 1-mm capillary tip. 32.2 Oil Bath, equipped with an electrical heating device so the bath can be maintained at 155°C. 32.3 Analytical Balance, capable of weighing to 0.0001 g.
33. Reagents
33.1 Chromium Trioxide Solution (30 %)—Dissolve 30 g of chromic trioxide (CrO 3 ) in 70 ml of water. 33.2 Nitrogen—Use a nitrogen cylinder with suitable reduc- ing valve. 33.3 Potassium Iodide (KI). 33.4 Sodium Bicarbonate (NaHCO 3 ), powder. 33.5 Sodium Hydroxide Standard Solution (0.02 N), carbon dioxide free. 33.6 Sodium Thiosulfate Standard Solution (0.02 N). 33.7 Sulfuric Acid Solution (10 %)—Carefully add 60 mL of concentrated sulfuric acid to 940 mL of water, slowly while stirring. 33.8 Phenolphthalein Indicator Solution, 1 %. 33.9 Starch Indicator Solution.
34. Procedure
34.1 Weigh to the nearest 0.0001 g, 70 to 80 mg of hydroxypropylcellulose, previously dried at 105°C for 1 h, into the reaction flask. Add 10 mL of water and swirl gently for 5 min. Then add 10 mL of chromium trioxide solution and assemble the apparatus as shown in Fig. 2. 34.2 Immerse the reaction flask in the oil bath slightly above the level ofthe chromium trioxide solution. Start the condenser cooling water, and pass nitrogen gas through the flask at a rate of 70 to 75 mL/minute. Raise the temperature of the oil bath to 155°C over a 30-min time period, and maintain it at that temperature throughout the determination. Too rapid an initial rise in temperature results in high blanks. 34.3 Monitor the temperature of the reaction mixture using a thermocouple or thermometer in a well as shown in Fig. 2. When the temperature of the reaction mixture reaches 101 to 103°C, add water through the water inlet until the temperature drops to 96 to 98°C. Continue this cycle until 100 mL of distillate has been collected. Detach the condenser from the distillation head and wash with water, collecting the washings in the flask containing the distillate. 34.4 Add 2 or 3 drops of phenolphthalein indicator solution to the distillate and titrate with 0.02 N sodium hydroxide solution until a pink color persists momentarily. Place the flask on a hot plate, boil for one minute, cool, and continue the titration to a pink color which persists for 10 s. Record the total volume of sodium hydroxide solution used, A. 34.5 Add 0.5 g of sodium bicarbonate to the flask and swirl to mix. Then add 10 mL of sulfuric acid solution (10 %), swirl, and allow to stand until carbon dioxide evolution ceases. Add 1 g of potassium iodide, stopper, and mix well to dissolve. Allow the solution to stand in the dark for 5 min. Titrate the liberated iodine with 0.02 N sodium thiosulfate solution,adding starch indicator near the end point. Record the total volume of sodium thiosulfate solution used, B. 34.6 Empirical Factor, K—The empirical factor, K, for each apparatus is obtained by running a blank determination in which the hydroxypropylcellulose is omitted.