Packaging and storage—
Preserve in tight containers, at a temperature not exceeding 30
. Protect from freezing.
Labeling—
The label indicates the name and amount of any substance added as a surface-active agent.
Identification—
A: Infrared Absorption 
197K
—
Proceed as directed, except to use the residue obtained in the
Loss on drying test as the test specimen.
B:
Mix 10 g of it with 0.3 g of triethyl citrate, pour onto a glass slide, and allow the water to evaporate: a clear film is formed.
Viscosity 911—
Equip a suitable rotational viscosimeter with an adapter system consisting of a measuring cylinder and a spindle. The measuring cylinder has an internal diameter of 2.762 cm and a depth of 13.50 cm; the spindle is 2.515 cm in diameter and 9.074 cm in height, and has a shaft that is 0.40 cm in diameter. Mix the Dispersion, pipet 16 mL of it into the measuring cylinder, and adjust the temperature of the dispersion and the adapter to 20 ± 0.1
. With the spindle rotating at 30 rpm, immediately observe and record the scale reading. Convert the scale reading to centipoises by multiplying the reading by the constant for the viscosimeter, the adapter system, and the speed employed. The viscosity is not more than 15 centipoises.
Loss on drying 731—
Dry it at 110
for 6 hours: it loses between 68.5% and 71.5% of its weight.
Residue on ignition 281—
Using mild heating conditions (e.g., steam bath, sand bath) to avoid loss of material, evaporate the Dispersion to dryness prior to ignition: not more than 0.2% residue is obtained, calculated on the undried Dispersion basis.
Heavy metals, Method II 231—
Using mild heating conditions (e.g., steam bath, sand bath) to avoid loss of material, evaporate the Dispersion to dryness prior to wetting with sulfuric acid and ignition: the color of the solution from the
Test Preparation is not darker than that of the solution from the
Standard Preparation (0.002%).
Limit of monomers—
pH 2.0 Phosphate buffer, fortieth-molar; Mobile phase; and Chromatographic system—
Prepare as directed in the test for
Limit of monomers under
Methacrylic Acid Copolymer.
Standard solution—
Prepare a solution in methanol having a known concentration of about 2 µg per mL each of methacrylic acid and ethyl acrylate. To 50.0 mL of this solution add 25.0 mL of water, and mix.
Test solution—
Dissolve 1.0 g of the Dispersion in 50.0 mL of methanol, add 25.0 mL of water, and mix.
Procedure—
Proceed as directed in the test for
Limit of monomers under
Methacrylic Acid Copolymer. The total amount of monomers found is not more than 0.01%, based on the weight of the Dispersion taken.
Coagulum content—
Accurately weigh a stainless steel sieve having 90-µm openings, and filter 100 g of the Dispersion through it. Wash the sieve with distilled water until a clear filtrate is obtained, and dry the sieve to constant weight at 110
: the weight of the residue does not exceed 1000 mg (1%).
Assay—
Using about 2.5 g of the Dispersion, accurately weighed, proceed as directed in the
Assay under
Methacrylic Acid Copolymer. Calculate, on the dried basis, the percentage of methacrylic acid units in the portion of Dispersion taken by the formula:
860.9[
VN/
W(100
L)],
in which
V is the volume, in mL, of titrant consumed;
N is the normality of the titrant;
W is the weight, in g, of Dispersion taken for the
Assay; and
L is the percentage of the loss on drying value for the Dispersion.
