By rotating method, the cellulose ether samples of specified quality were added to 250 ml glass beaker, then 250 g hot water of about 90 degrees Celsius was added. The cellulose ether was fully stirred with glass rod to form a uniform dispersion system in hot water. At the same time, the beaker was cooled in air. When the solution was in the critical viscosity range, the temperature of cellulose ether was increased. Stop mixing; when the solution is cooled in the air to uniform color, place the beaker in the constant temperature water bath pot, and keep the temperature to the specified temperature (e.g. 20 degrees Celsius), with an error of (+0.1 degrees Celsius); after 2 hours (from the time of contact between cellulose ether and hot water), use a thermometer to measure the temperature of the solution center, if the temperature has reached the specified temperature. The rotator of the rotary viscometer is inserted into the solution to a specified depth. After standing for 5 minutes, the basic viscosity is determined. |
