How to detect the viscosity of hydroxypropyl methyl cellulose

Extract 2.0g of hydroxypropyl methylcellulose HPMC sample dried to constant weight into a beaker, add 98ml of 80~90℃ hot water to make a 2.0% (g/g) solution, stir for about 20min, then put in ice Cool in the bath for 50min, continue to mix during the cooling process, remove air bubbles, and adjust the weight on the tray balance or electronic balance until the required amount; put the solution in a constant temperature bath, so that the temperature is 20 ℃ ± 0.1 ℃; Use NDJ-1 type rotary viscometer or B type viscometer to measure its viscosity, measure three times and take the average value


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