ASTM_D_1303_-_55_1979e1_scan.pdf

AMERICAN NATIONAL STANOARDHV ASTM D 1303-55(Reapproved 1979)Standard Test Method for TOTAL CHLORINE IN VINYL CHLORIDE POLYMERS AND COPOLYMERS1 This standard is issued under the fixed designation D 1303;the number immediately following the designation indicates the year of original adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.NOTESections 3,4,and 8 were added editorially in October 1979.1.Scope 1.1 This method covers the determination of total chlorine in vinyl chloride polymers and copolymers.The method does not distinguish between poly(vinyl chloride)and poly(vi-nylidene chloride).2.Summary of Method 2.1 The organic matter is destroyed by hot sodium peroxide,and the chlorine is converted to chloride.The chloride is precipitated as silver chloride with an excess of standard silver ni-trate,and this excess is determined by titration with standard thiocyanate solution using ferric nitrate indicator and nitrobenzene to depress the solubility of the silver chloride.The amount of silver nitrate required to precipitate the chlo-ride is a measure of the total chlorine content of the sample.3.Significance 3.1 The purpose of this method is the accu-rate determination of the amount of chlorine present in vinyl chloride polymers and copol-ymers.This method can also be applied to other plastics that could contain chlorinated species.4.Interferences 4.1 Any species that contains chlorine,bro-mine,or iodine will interfere with this test method.5.Apparatus 5.1 Parr Peroxide Bomb,Series 2100,22-ml,gas fired.2 6.Purity of Reagents 6.1 Purity of ReagentsReagent grade chemicals shall be used in all tests.Unless otherwise indicated,it is intended that all re-agents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society,where such spec-ifications are available.3 Other grades may be used,provided it is first ascertained that the reagent is of sufficiently high purity to permit use without lessening the accuracy of the deter-mination.6.2 Purity of WaterUnless otherwise indi-cated,references to water shall be understood to mean distilled water or water of equal purity.7.Reagents and Materials 7.1 Powdered Sugar(preferably cp sucrose).7.2 Sodium Peroxide,cp,calorific grade,as-say 95%,min,as Na202.NOTE 1Keep Na202 in a tightly closed con-tainer,away from moisture.1 This method is under the jurisdiction of ASTM Com-mittee D-20 on Plastics and is the direct responsibility of Subcommittee D20.70 on Analytical Methods.Current edition approved Sept.12,1955.Originally issued 1953.2 The Parr Peroxide Bomb may be obtained from the Pan-Instrument Co.,Moline,111.Parr electrically fired bombs may be used in place of the gas fired peroxide bombs,provided tests of both apparatus have been conducted to demonstrate reproducible agreement of results.3 Reagent Chemicals,American Chemical Society Spec-ifications,Am.Chemical Soc.,Washington,D.C.For sug-gestions on the testing of reagents not listed by the American Chemical Society,see Reagent Chemicals and Standards,by Joseph Rosin,D.Van Nostrand Co.,Inc.,New York,N.Y.,and the United States Pharmacopeia.504 NOTICE:This standard has either been superseded and replaced by a new version or withdrawnContact ASTM International(www.astm.org)for the lastest informationD1303 7.3 Nitric Acid(sp gr 1.42)Concentrated nitric acid(HNO3).7.4 Silver Nitrate Solution(0.1 N)Prepare and standardize a 0.1N solution of silver nitrate(AgNOs).7.5 Ammonium or Potassium Thiocyanate Solution(0.1 N)Prepare and standardize a 0.1 N solution of either potassium thiocya-nate(KCNS)or ammonium thiocyanate(NH4CNS).7.6 Ferric Nitrate Solution(50 g Fe(N03)3/tore)Dissolve 50 g of ferric nitrate(Fe(N03)3)in water and dilute to 1 litre.7.7 Nitrobenzene,cp.8.Precautions 8.1 A careful reading of Parr Manual No.121 on the method and precautions used in this method is suggested.8.2 Caution:Nitrobenzene is toxic;avoid contact with the skin.9.Preparation of Sample 9.1 Dry the sample for 45 min in an oven at 100 lCinan atmosphere of CO2 or nitro-gen.Store in a desiccator.NOTE 2Moisture pick-up is a problem;the dried sample should be used promptly and should not be stored for prolonged periods.10.Procedure 10.1 To a clean dry 22-ml Parr bomb cup,add 0.200 to 0.225 g of finely powdered sample.Add 0.5 g of dry powdered sugar and a stand-ard measure(15 g)of Na202.Close the bomb tightly with the lid and the retaining rings,and shake vigorously to mix the contents.Tap the bomb lightly on the bench to dislodge particles sticking to the cap and to the upper portion of the bomb cup.Set the bomb over the hole in a steel housing supported on a tripod.A small steel chamber with an access door and a small sight hole built over the tripod is desirable for reasons of safety.10.2 Add 2 ml of water to the depression in the bomb cover.Apply a very hot bunsen flame to the bottom of the bomb.Adjust the air to the burner to give a cone