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1、A Reference number ISO 10398:1998(E) INTERNATIONAL STANDARD ISO 10398 First edition 1998-07-01 Rubber Identification of accelerators in cured and uncured compounds Caoutchouc Identification des acclrateurs dans les mlanges vulcaniss ou non Copyright International Organization for Standardization Pro
2、vided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/22/2007 20:05:30 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 10398:1998(E) ISO 1998 All rights reserved. Unless otherwise specified, no part of this publication may
3、 be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the publisher. International Organization for Standardization Case postale 56 CH-1211 Genve 20 Switzerland Internetcentraliso.ch X.400c=ch; a=400
4、net; p=iso; o=isocs; s=central Printed in Switzerland ii Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committee
5、s. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the Inter
6、national Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member b
7、odies casting a vote. International Standard ISO 10398 was prepared by Technical Committee ISO/TC 45, Rubber and rubber products. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/22/2007
8、20:05:30 MDTNo reproduction or networking permitted without license from IHS -,-,- INTERNATIONAL STANDARD ISOISO 10398:1998(E) 1 Rubber Identification of accelerators in cured and uncured compounds WARNING Persons using this International Standard should be familiar with normal laboratory practice.
9、This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user to establish appropriate safety and health practices and to ensure compliance with any national regulatory conditions. 1 Scope 1.1 This International Standard s
10、pecifies methods using gas chromatography (GC) and thin layer chromatography (TLC) for the separation and identification of the following classes of accelerators in vulcanized and unvulcanized compounds: thiazoles sulfenamides thiurams and dithiocarbamates guanidines dithiodimorpholine 1.2 When 2-me
11、rcaptobenzothiazole (MBT) is identified and no sulfenamides are present, it is not possible to establish if the original accelerator was MBT and/or its salts or 2,2-dibenzothiazoledisulfide (MBTS) as each of these accelerators may be produced from the others during the vulcanization process. 1.3 Whe
12、n sulfenamides are identified, it is not possible to establish if MBT and/or its salts and MBTS are present as these accelerators may be produced from 2-mercaptobenzothiazole sulfenamides during the vulcanization process. 1.4 The methods do not distinguish thiurams and dithiocarbamates derived from
13、the same amines. 1.5 From the morpholine identification it is not possible to determine if the initial accelerator is 2-morpholinothio- benzothiazole (MBS) or dithiomorpholine as morpholine may be formed from MBS and dithiodimorpholine during the vulcanization process. 1.6 The separation of accelera
14、tor compounds from unvulcanized compounds is relatively straightforward whereas separation from vulcanized compounds is difficult due to the lesser ability of solvents to penetrate the vulcanized matrix. 1.7 Some compounding ingredients may interfere with method B. In such cases methods A or C shall
15、 be used. 2 Principle 2.1 Method A Identification of amines via GC and thiazoles via TLC 2.1.1 A portion of the sample compound is refluxed with hydrochloric acid (HCl) to hydrolyze sulfenamides, thiurams and dithiocarbamates. The resulting amine hydrochlorides are separated and purified. After puri
16、fication, the amines are separated by GC as their trifluoroacetamide derivatives. Identification may also be effected by comparison of GC retention times of sample and standard trifluoroacetamides, prepared and analyzed under the same analysis conditions. Copyright International Organization for Sta
17、ndardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/22/2007 20:05:30 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 10398:1998(E) ISO 2 2.1.2 The HCl reflux solubles and insolubles, remaining after amine
18、s are separated by distillation, are combined and refluxed with sodium hydroxide (NaOH). The resultant sodium salts of the thiazoles formed from free thiazoles and from MBT produced during the HCl reflux of sulfenamides and other MBT derivatives are separated by extraction and purified. After purifi
19、cation, the thiazoles are separated by TLC and qualitatively detected by comparison of Rf and colours of the sample TLC spots with Rf and colours of standard thiazole spots prepared and analyzed under the same analysis conditions. 2.2 Method B Identification of amines, guanidines, thiazoles and dith
20、iocarbamates via TLC 2.2.1 Accelerators are extracted from the sample with suitable solvents. 2.2.2 A portion of the extract is hydrolyzed with HCl and the resultant amines separated and qualitatively detected by TLC through comparison of Rf and colours of sample TLC spots with standard TLC spots pr
21、epared and analyzed under the same analysis conditions. 2.2.3 A second portion of the extract is hydrolyzed with ammonium hydroxide (NH4OH) and the ammonium salts of the thiazoles, dithiocarbamates and sulfenamides are separated and qualitatively detected by TLC through comparison of Rf and colours
22、of sample TLC spots with standard TLC spots prepared and analyzed under the same analysis conditions. 2.3 Method C Identification of thiurams, thiazoles, sulfenamides and guanidines via TLC 2.3.1 Accelerators are extracted from the sample with suitable solvents. 2.3.2 The extracted accelerators are
23、separated and qualitatively detected by TLC through comparison of Rf and colours of sample TLC spots with standard TLC spots prepared and analyzed under the same analysis conditions. 3 Method A Identification of amines via GC and thiazoles via TLC 3.1 Apparatus Ordinary laboratory apparatus and 3.1.
24、1 Several GC column types and operating conditions may be used providing column type and operating conditions are chosen which give good separation of the trifluoroacetamides from other eluting components. An example of trifluoroacetamide separation is given in figure 1 together with column type and
25、 GC operating conditions. 3.1.2 TLC plates covered with a silica gel layer. NOTE TLC plates HPTLC Kieselgel 60, 10 cm x 10 cm, supplied by Merck, have been found to be suitable. Other plates with similar qualities may be used. 3.1.3 Desiccator for storing activated TLC plates. 3.1.4 Developing tanks
26、 for TLC. 3.1.5 Sprayers for spraying the spray reagents. 3.1.6 Microsyringe for GC, capacity 10 mm 3 (l). 3.1.7 Microinjector or micropipettes for TLC, capacity 0,01 cm 3 3.1.8 Filter paper, fast flowing. 3.2 Reagents 3.2.1 Mixture of isopropanol, hydrochloric acid and water, 50:25:25 (V/V/V). Copy
27、right International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/22/2007 20:05:30 MDTNo reproduction or networking permitted without license from IHS -,-,- ISOISO 10398:1998(E) 3 Trifluoroacetamides of:Colum
28、n:Capillary, IIP-5 (cross-linked 5 % phenyl silicon) (1)dimethyl-amine25 m x 0,2 mm (0,33 mm film) (2)diethyl-amine (3)morpholineCarrier:Helium, 10 kPa (4)piperidine (5)cyclohexyl-amineInjection:1 mm 3 (l), on-column (6)aniline (7)dibutyl-amineDetector:Mass selective (8)ethyl-phenyl-amine Oven progr
29、amme: isothermal 1: 35 C, 4 min ramp 1: 6 C/min isothermal 2: 200 C, 0,5 min ramp 2: 15 C, 15 min isothermal 3: 300 C, 15 min Figure 1 Separation of trifluoroacetamides Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1
30、/9972545001 Not for Resale, 04/22/2007 20:05:30 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 10398:1998(E) ISO 4 3.2.2 Isopropanol. 3.2.3 Sodium hydroxide pellets. 3.2.4 Hydrochloric acid solution, prepared by diluting 1 volume of concentrated hydrochloric acid with
31、1 volume of water. 3.2.5 Trifluoracetic anhydride. 3.2.6 Methylene chloride. 3.2.7 Sodium sulfate, anhydrous. 3.2.8 Sodium hydroxide solution, 40 g/dm 3. 3.2.9 n-heptane. 3.2.10 Eluent A: mixture of n-hexane55 parts in volume methylene chloride35 parts in volume ethyl ether35 parts in volume methano
32、l15 parts in volume acetic acid15 parts in volume 3.2.11 Spray reagent B: 1 % solution of 2,6-dichloroquinone-4-chlorimide in ethanol. 3.2.12 Toluene. 3.2.13 n-butanol. 3.2.14 Spray reagent F: 5 % bismuth nitrate solution in 0,5 mol/dm 3 nitric acid. 3.3 Procedure 3.3.1 Identification of the amines
33、3.3.1.1 Cut 2 g to 10 g of a representative sample into small pieces or thinly sheet about 10 g of a representative sample on a laboratory mill to about 0,25 mm to 0,5 mm thickness. Maintain the sample at the lowest possible temperature during the milling in order to avoid thermal degradation of the
34、 accelerators. 3.3.1.2 Reflux the small pieces or thinly sheeted test portion for 2 h with 100 cm 3 of the mixture of isopropanol, hydrochloric acid and water (3.2.1). 3.3.1.3 Filter the boiling solution through fast flowing filter paper (3.1.8) into a conical flask. Wash the reactor vessel and the
35、insoluble portion in the filter with 20 cm 3 of boiling isopropanol (3.2.2) into the same conical flask. 3.3.1.4 Save the washed insoluble portion in the filter. 3.3.1.5 Adjust the solution to a volume of about 10 cm 3 and cool at room temperature. 3.3.1.6 Make the solution strongly alkaline by addi
36、ng sodium hydroxide pellets (3.2.3). 3.3.1.7 Distil the solution under a slow flow of nitrogen and recover the distillate by bubbling through a few cm 3 of the hydrochloric acid solution (3.2.4) into a conical flask. Copyright International Organization for Standardization Provided by IHS under lice
37、nse with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/22/2007 20:05:30 MDTNo reproduction or networking permitted without license from IHS -,-,- ISOISO 10398:1998(E) 5 3.3.1.8 Stop the distillation when 2 cm 3 to 3 cm3 of solution remains in the distillation flask. 3.3.1.9 A
38、dd to the distillation residue the washed insoluble portion (3.3.1.4) and save the mixture. 3.3.1.10 Concentrate the distilled solution to a volume of 2 cm 3 to 3 cm3. 3.3.1.11 Transfer the concentrated solution into a 10 cm 3 distillation vessel and heat in a sand bath until only a few drops of sol
39、ution remain in the vessel, then evaporate the solution to dryness by heating in an oven at 80 C overnight. 3.3.1.12 Cool the dry residue at room temperature, pour 2 cm 3 of trifluoroacetic anhydride (3.2.5) into the vessel and immediately connect to a reflux condenser. In order to prevent moisture
40、from entering the vessel, connect the upper end of the reflux condenser with a tube filled with calcium chloride. 3.3.1.13 Reflux for 1 h in an oil bath at 80 C to 90 C, disconnect the reflux condenser, concentrate the solution at a volume of about 0,5 cm 3 and cool to room temperature. 3.3.1.14 Add
41、 drop by drop 10 cm 3 of water and transfer the solution to a separating funnel. 3.3.1.15 Add 5 cm 3 of methylene chloride (3.2.6), shake, allow the two layers to separate and recover the layer of methylene chloride. Repeat the extraction two times with methylene chloride. Discard the aqueous layer.
42、 3.3.1.16 Wash the methylene chloride extract with water to pH 7 to ensure that all the trifluoroacetic acid has been removed. 3.3.1.17 Add about 0,1 g of anhydrous sodium sulfate (3.2.7) to the methylene chloride extract and shake to eliminate any trace of water, filter through filter paper and con
43、centrate the solution to a volume of about 0,5 cm 3. 3.3.1.18 Inject a suitable amount of the solution into the injection port of the gas chromatograph (3.1.1) and record the chromatogram. 3.3.1.19 Compare the retention times of the peaks obtained from the sample solution with the retention times of
44、 the peaks obtained from solutions containing known amides under the same gas chromatographic operating conditions. NOTE If the trifluoroacetamides of the amines to be identified are not available, it is possible to prepare them by carrying out the procedure described using the pure accelerators to
45、produce the amines to be identified. These standard solutions can be stored at 5 C for at least 1 year. 3.3.2 Preparation of the TLC plates 3.3.2.1 Activate the TLC plates (3.1.2) by heating in an oven at 105 C for 2 h or at 80 C overnight. 3.3.2.2 Cool the activated plates in the desiccator (3.1.3)
46、. NOTE The activated plates can be stored in the desiccator for 10 days without further activation. 3.3.2.3 Just before use, inscribe a start line on the activated plate 15 mm to 20 mm from the edge of the plate. 3.3.2.4 Different solutions may be applied on the same plate, along the start line. The
47、 distance between the two spots shall be at least 25 mm. 3.3.3 Procedure 3.3.3.1 Pour 50 cm 3 of isopropanol (3.2.2) and 50 cm3 of the sodium hydroxide solution (3.2.8) into the vessel containing the mixture 3.3.1.9 and reflux for 2 h. 3.3.3.2 Filter the boiling solution through filter paper and was
48、h the reaction vessel and the filter with a few cm 3 of boiling isopropanol. Quantitatively transfer the filtered solution and washings into a separating funnel. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/22/2007 20:05:30 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 10398:1998(E) ISO 6 3.3.3.3 Extract this