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 7.0 mL 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
, of the Microcrystalline Cellulose taken by the formula:
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
, of the solvent by the formula:
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, [
by interpolation, using the Intrinsic Viscosity Table
in the Reference Tables
section. Calculate the degree of polymerization, P,
by the formula:
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.