Purified Rayon
» Purified Rayon is a fibrous form of bleached, regenerated cellulose.
Alkalinity or acidity—
Immerse about 10 g in 100 mL of recently boiled and cooled water, and decant 25-mL portions of the water, with the aid of a glass rod, into each of two dishes. To one portion add 3 drops of phenolphthalein TS, and to the other portion add 1 drop of methyl orange TS: neither portion appears pink when viewed against a white background.
Residue on ignition 
281
:
not more than 1.50%, determined on a 5.0-g test specimen.
281:
not more than 1.50%, determined on a 5.0-g test specimen.
Acid-insoluble ash—
To the residue obtained in the test for Residue on ignition, add 25 mL of 3 N hydrochloric acid, and boil for 5 minutes. Collect the insoluble matter on a tared filtering crucible, wash with hot water, ignite, and weigh: the residue weighs not more than 63.0 mg (1.25%).
Water-soluble substances—
Proceed as directed in the test for Water-soluble substances under Purified Cotton: the residue weighs not more than 100 mg (1.0%).
Fiber length and absorbency—
Remove it from its wrappings, and condition it for not less than 4 hours in a standard atmosphere of 65 ± 2% relative humidity at 21 ± 1.1
. Determine the Fiber length and Absorbency as follows.
. Determine the Fiber length and Absorbency as follows.
Fiber length—
Determine the fiber length of Purified Rayon as directed for Fiber Length under Cotton 691: not less than 70.0%, by weight, of the fibers are 19 mm or greater in length, and not more than 5.0%, by weight, of the fibers are 6.3 mm or less in length.
691: not less than 70.0%, by weight, of the fibers are 19 mm or greater in length, and not more than 5.0%, by weight, of the fibers are 6.3 mm or less in length.
Absorbency—
Proceed as directed for the Absorbency Test under Cotton 691: submersion is complete in 5 seconds, and the rayon retains not less than 16 times its weight of water.
691: submersion is complete in 5 seconds, and the rayon retains not less than 16 times its weight of water.
Other requirements—
It meets the requirements of the tests for Dyes and Other foreign matter under Purified Cotton.
Auxiliary Information—
Please check for your question in the FAQs before contacting USP.
| Topic/Question | Contact | Expert Committee |
| Monograph | Radhakrishna S Tirumalai, Ph.D.
Senior Scientist 1-301-816-8339 |
(GTMDB05) General Toxicology and Medical Device Biocompatibility |
USP32–NF27 Page 3482