ASTM D3876-96(R2021) pdf free download

ASTM D3876-96(R2021) pdf free download.Standard Test Method for Methoxyl and Hydroxypropyl Substitution in Cellulose Ether Products by Gas Chromatography
1. Scope
1.1 This test method is applicable to the determination of methoxyl and hydroxypropyl substitution content in cellulose ether products by a Zeisel-gas chromatographic technique. 1.2 This test method is not suitable for use for the analysis of hydroxypropyl-cellulose due to its very high substitution level. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appro- priate safety, health, and environmental practices and deter- mine the applicability of regulatory limitations prior to use. For specific hazard statements, see Section 2, 11.1.4, and 11.1.7. 1.4 This international standard was developed in accor- dance with internationally recognized principles on standard- ization established in the Decision on Principles for the Development of International Standards, Guides and Recom- mendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Summary of Test Method
2.1 When methyl cellulose or hydroxypropyl methyl cellu- lose is reacted with hydriodic acid, 1 mol of methyl iodide and 1 mol of isopropyl iodide are liberated for each mole of methoxyl and hydroxypropoxyl that is substituted on the cellulose chain. The methyl iodide and isopropyl iodide are extracted in situ with o-xylene and quantitated by gas chroma- tography using an internal standard technique.
3. Significance and Use
3.1 This test method determines the methoxyl and hydroxy- propoxyl content of cellulose ethers by a Zeisel-gas chromato- graphic technique. 3.2 Substitution levels affect solution properties, rheology, viscosity, and many other properties of the polymer.
4. Apparatus
4.1 Gas Chromatograph, 2 with thermal conductivity detec- tor and heated injection port. 4.2 Electronic Integrator. 3 4.3 Stainless Steel Tubing, 4 9.5 mm in outside diameter and 1981 mm in length, packed with reagent in 5.8. 4.4 Syringes, 10 and 100 µL. 4.5 Reaction Vials, Caps, and Heating Block. 5
5. Reagents
5.1 Purity of Reagents—Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the Commit- tee on Analytical Reagents of the American Chemical Society, where such specifications are available. 6 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination.