Purified Rayon
»Purified Rayon is a fibrous form of bleached,regenerated cellulose.
Alkalinity or acidity— Immerse about 10g in 100mLof recently boiled and cooled water,and decant 25-mLportions of the water,with the aid of a glass rod,into each of two dishes.To one portion add 3drops of phenolphthalein TS,and to the other portion add 1drop of methyl orange TS:neither portion appears pink when viewed against a white background.
Residue on ignition á281ñ: 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 25mLof 3Nhydrochloric acid,and boil for 5minutes.Collect the insoluble matter on a tared filtering crucible,wash with hot water,ignite,and weigh:the residue weighs not more than 63.0mg (1.25%).
Water-soluble substances— Proceed as directed in the test for Water-soluble substancesunder Purified Cotton:the residue weighs not more than 100mg (1.0%).
Fiber length and absorbency— Remove it from its wrappings,and condition it for not less than 4hours in a standard atmosphere of 65±2%relative humidity at 21±1.1.Determine the Fiber lengthand Absorbencyas follows.
Fiber length— Determine the fiber length of Purified Rayon as directed for Fiber Lengthunder Cotton á691ñ:not less than 70.0%,by weight,of the fibers are 19mm or greater in length,and not more than 5.0%,by weight,of the fibers are 6.3mm or less in length.
Absorbency— Proceed as directed for the Absorbency Testunder Cotton á691ñ:submersion is complete in 5seconds,and the rayon retains not less than 16times its weight of water.
Other requirements— It meets the requirements of the tests for Dyesand Other foreign matterunder Purified Cotton.
Auxiliary Information— Staff Liaison:Radhakrishna S Tirumalai,Scientist
Expert Committee:(GTB)General Toxicology and Biocompatibility
USP28–NF23Page 1708
Phone Number:1-301-816-8339