B: Transfer 1.3 g of Microcrystalline Cellulose, accurately weighed to 0.1 mg, to a 125-mL conical flask. Add 25.0 mL of water and 25.0 mL of 1.0 M cupriethylenediamine hydroxide solution. Immediately purge the solution with nitrogen, insert the stopper, and shake on a wrist action shaker, or other suitable mechanical shaker, until completely dissolved. Transfer an appropriate volume of the solution to a calibrated number 150 Cannon-Fenske, or equivalent, viscosimeter. Allow the solution to equilibrate at 25 ± 0.1 for not less than 5 minutes. Time the flow between the two marks on the viscosimeter, and record the flow time, t1, in seconds. Calculate the kinematic viscosity, (KV)1, of the Microcrystalline Cellulose taken by the formula:
t1(k1)
in which k1 is the viscosimeter constant (see Viscosity 911 ). Obtain the flow time, t2, for a 0.5 M cupriethylenediamine hydroxide solution using a number 100 Cannon-Fenske, or equivalent, viscosimeter. Calculate the kinematic viscosity, (KV)2, of the solvent by the formula:
t2(k2)
in which k2 is the viscosimeter constant. Determine the relative viscosity, rel, of the Microcrystalline Cellulose specimen taken by the formula:
(KV)1 / (KV)2
Determine the intrinsic viscosity, [ ]c, by interpolation, using the Intrinsic Viscosity Table in the Reference Tables section. Calculate the degree of polymerization, P, by the formula:
(95)[ ]c /WS[(l00 – %LOD)/100]
in which WS is the weight, in g, of the Microcrystalline Cellulose taken; and %LOD is the value obtained from the test for Loss on drying. The degree of polymerization is not greater than 350.
B: 取微晶纤维素1.3 g,准确称量到 0.1 mg,置于125-mL 锥形瓶中,加 25.0 mL 水和 25.0 mL 1.0 M的氢氧化铜乙二胺溶液。立即通氮气,盖上盖子,用手摇或其它的方式摇动使样品完全溶解,将7.0 mL 上述溶液转到一个已校正过的150号Cannon-Fenske粘度计或类似的粘度计中。在25 ± 0.1°平衡不少于5分钟,让液体流过粘度计上的两记号, 记录时间, t 1 , 单位秒. 按下式计算动力粘度, (KV)1:
t 1 ( k 1 ),
k 1-粘度计常数(see Viscosity <911> ). 记录0.5 M氢氧化铜乙二胺溶液流出100号Cannon-Fenske粘度计或类似粘度计的时间, t 2 . 按下式计算溶剂的动力粘度, (KV)2,:
t 2 ( k 2 ),
k 2 -粘度计常数. 按下式计算样品的相对粘度, rel,:
(KV)1 / (KV)2.
使用参照表部分的特性粘度表,通过加补法计算特性粘度, [ ]c,. 按下式计算聚合度, P,:
(95)[ ]c / WS [(l00 – %LOD)/100],
WS为所取样品重量, g, %LOD为测得的干燥失重值。聚合度不大于350。