Code of Federal Regulations Title 21. Food and Drugs § 21.177.1480 Nitrile rubber modified acrylonitrile-methyl acrylate copolymers

(i) Nitrogen content is in the range 16.5–19 percent as determined by Kjeldahl analysis.

(ii) Intrinsic viscosity in acetonitrile at 25° C is not less than 0.29 deciliter per gram as determined by ASTM method D1243–79, “Standard Test Method for Dilute Solution Viscosity of Vinyl Chloride Polymers,” which is incorporated by reference. Copies may be obtained from the American Society for Testing Materials, 100 Barr Harbor Dr., West Conshohocken, Philadelphia, PA 19428-2959, or may be examined at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202–741–6030, or go to:  http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

(iii) Residual acrylonitrile monomer content is not more than 11 parts per million as determined by gas chromatography.

(iv) Acetonitrile-soluble fraction after refluxing the base polymer in acetonitrile for 1 hour is not greater than 95 percent by weight of the basic copolymers.

(i) Extracted copolymer not to exceed 2.0 parts per million in aqueous extract obtained when a 100–gram sample of the basic copolymers is extracted with 250 milliliters of demineralized (deionized) water at reflux temperature for 2 hours.

(ii) Extracted copolymer not to exceed 0.5 part per million in n-heptane extract obtained when a 100–gram sample of the basic copolymers is extracted with 250 milliliters of reagent grade n-heptane at reflux temperature for 2 hours.