1、BSI Standards PublicationBS ISO 2028:2015Synthetic rubber latex Preparation of dry polymerBS ISO 2028:2015 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 2028:2015. It supersedes BS ISO 2028:1999 which is withdrawn.The UK participation in its preparation was e
2、ntrusted to Technical Committee PRI/50, Rubber - Raw, natural and synthetic, including latex and carbon black.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Use
3、rs are responsible for its correct application. The British Standards Institution 2015.Published by BSI Standards Limited 2015ISBN 978 0 580 89094 9ICS 83.040.10Compliance with a British Standard cannot confer immunity from legal obligations.This British Standard was published under the authority of
4、 the Standards Policy and Strategy Committee on 30 June 2015.Amendments/corrigenda issued since publicationDate T e x t a f f e c t e dBS ISO 2028:2015 ISO 2015Synthetic rubber latex Preparation of dry polymerLatex de caoutchouc synthtique Prparation du polymre secINTERNATIONAL STANDARDISO2028Fifth
5、edition2015-06-01Reference numberISO 2028:2015(E)BS ISO 2028:2015ISO 2028:2015(E)ii ISO 2015 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2015, Published in SwitzerlandAll rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any f
6、orm or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISOs member body in the country of the requester.ISO copyright officeCh. de Blandonn
7、et 8 CP 401CH-1214 Vernier, Geneva, SwitzerlandTel. +41 22 749 01 11Fax +41 22 749 09 47copyrightiso.orgwww.iso.orgBS ISO 2028:2015ISO 2028:2015(E)Foreword iv1 Scope . 12 Normative references 13 Principle 14 Reagents 15 Apparatus . 26 Procedure. 36.1 General . 36.2 Styrene-butadiene (SBR) latices (o
8、f less than 55 % solids content) 36.3 Carboxylated (X-SBR and X-NBR) latices 36.4 Nitrile (NBR) latices . 46.5 Concentrated latices (more than 55 % solids content) . 47 Report 4 ISO 2015 All rights reserved iiiContents PageBS ISO 2028:2015ISO 2028:2015(E)ForewordISO (the International Organization f
9、or 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 committees. Each member body interested in a subject for which a technical committee has been established has th
10、e 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 International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.The proce
11、dures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editoria
12、l rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any patent rights i
13、dentified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents).Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement.For an explanati
14、on on the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the WTO principles in the Technical Barriers to Trade (TBT), see the following URL: Foreword Supplementary information .The committee responsible for this document
15、 is ISO/TC 45, Rubber and rubber products, Subcommittee SC 3, Raw materials (including latex) for use in the rubber industry.This fifth edition cancels and replaces the fourth edition (ISO 2028:1999), which has been technically revised with the following modifications. Clause 2 “Normative references
16、” has been updated. In 4.1, the note giving information on which company may provide polyamine polyelectrolytes, has been deleted.iv ISO 2015 All rights reservedBS ISO 2028:2015Synthetic rubber latex Preparation of dry polymerWARNING Persons using this International Standard should be familiar with
17、normal laboratory practice. This International 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.
18、1 ScopeThis International Standard specifies four methods for the isolation of dry polymer from synthetic polymer latices containing anionic surfactants, for the purpose of subsequent testing. Tests to be performed include the determination of the Mooney viscosity, the bound-styrene or acrylonitrile
19、 content in the polymer chain or the mill shrinkage.Because of the wide variety of surfactants and stabilizers used in the manufacture of synthetic rubber latices, there is not one method suitable for all latices. The methods given in this International Standard are suitable for a wide variety of la
20、tices, but their applicability is to be confirmed for individual types. Latices containing non-ionic stabilizers, in particular, may be resistant to coagulation.These methods are not necessarily suitable, without modification, for latices containing polymers having high tack.The dry polymer as isola
21、ted may contain residual organic acids or their aluminium salts which may affect the properties of the polymer and which are to be taken into account when performing analytical tests.2 Normative referencesThe following documents, in whole or in part, are normatively referenced in this document and a
22、re indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 123, Rubber latex SamplingISO 124, Latex, rubber Determination of total solids content3 PrincipleTh
23、e latex is coagulated in the presence of an antioxidant, using different procedures depending on the type of latex. The resultant crumb is washed with water and dried in a ventilated oven at 70 C to constant mass.NOTE Freezing is also a suitable method for the isolation of some latices; sufficient d
24、etails of the method are not available for inclusion in this edition of ISO 2028.4 ReagentsDuring the preparation of the reagent solutions and the isolation of the polymer, use only distilled water or water of equivalent purity.INTERNATIONAL STANDARD ISO 2028:2015(E) ISO 2015 All rights reserved 1BS
25、 ISO 2028:2015ISO 2028:2015(E)4.1 Coagulant ACoagulant A is an aqueous solution of a polyamine polyelectrolyte, prepared by dissolving 2,5 g of polyamine polyelectrolyte in 1 dm3of hot, 50 C water and then diluting the resultant solution to 10 dm3.NOTE Any residues of polyamine electrolyte left in t
26、he polymer following isolation are likely to interfere in the determination of bound acrylonitrile.4.2 Coagulant BCoagulant B is a solution of aluminium sulfate in dilute sulfuric acid. Prepare dilute sulfuric acid by slowly and cautiously adding 82 cm3of concentrated sulfuric acid to 1 dm3of water
27、and cooling. Separately, prepare a solution of aluminium sulfate by adding 200 cm3of 500 g/dm3aluminium sulfate solution to 200 cm3of water and straining through a piece of gauze. Add the diluted aluminium sulfate solution to the diluted sulfuric acid and adjust the volume to 1,5 dm3with water.4.3 A
28、ntioxidant, for example trinonyl phenyl phosphite (TNPP).Prepare an aqueous emulsion of antioxidant containing 25 g of antioxidant in 100 cm3of emulsion.The antioxidant chosen should preferably be one known to be suitable for use with the polymer to be isolated.4.4 Aluminium sulfate solution, prepar
29、ed by dissolving 4 g of aluminium sulfate in water and diluting the resultant solution to100 cm3.4.5 Ethanol, minimum purity 99 %.5 ApparatusStandard laboratory equipment plus the following.5.1 Stainless-steel beaker, 5 dm3capacity.5.2 Graduated cylinders, 10 cm3, 500 cm3and 1 000 cm3capacity.5.3 El
30、ectric stirrer, with two propeller-type blades of approximately 35 mm diameter, mounted 50 mm apart at right angles to the shaft.5.4 Magnetic stirrer.5.5 Suitable device for injecting steam, fed from a low-pressure source.NOTE Steam is the most efficient method of heating liquids rapidly.5.6 Gauze f
31、ilter, e.g. cheese cloth.5.7 Drying pan, aluminium or enamel-lined pan with a suitable surface area (approximately 500 cm2) on which to spread out the crumb for drying. The pan should be relatively light in weight.5.8 Ventilated oven, capable of being maintained at 70 C 5 C.5.9 Balance, capable of b
32、eing read to 0,1 g.2 ISO 2015 All rights reservedBS ISO 2028:2015ISO 2028:2015(E)6 Procedure6.1 GeneralUse a test sample of the latex prepared by one of the methods described in ISO 123.If the solids content of the latex is not known, determine it in accordance with ISO 124.6.2 Styrene-butadiene (SB
33、R) latices (of less than 55 % solids content)6.2.1 If it is not known whether or not the latex contains an antioxidant, transfer a portion of the test sample containing approximately 100 g of dry polymer to a clean, dry beaker and add 10 cm3of the antioxidant emulsion (4.3). Stir well.6.2.2 Transfer
34、 2 dm3 50 cm3of coagulant A (4.1) to a 5 dm3stainless-steel beaker (5.1) and heat to 65 C 5 C by injecting steam (see 5.5).Introduce the electric stirrer and stir at approximately 105 rad/s (1 000 r/min) while adding, in a slow stream, a quantity of latex containing approximately 100 g of dry polyme
35、r with antioxidant (see 6.2.1).Continue stirring for 1 min to ensure uniform mixing, then slowly add 15 cm3of coagulant B (4.2) dropwise. If complete precipitation is not achieved with the formation of fine crumbs and a clear serum, add a further 1 cm3of coagulant B.6.2.3 Strain through a clean gauz
36、e (5.6) and wash the residue of precipitated rubber particles with water at 50 C 5 C for 120 s 15 s.Allow the gauze to drain, then wrap it around the precipitated rubber and transfer it to a beaker containing water at 40 C 5 C.Allow to soak for a further 120 s 15 s while holding the gauze under the
37、water and squeezing gently with the fingers.Remove the gauze containing the crumbs from the water and squeeze to eliminate as much water as is practical.6.2.4 Transfer the damp polymer crumbs to a suitable pan (5.7) lined with a double layer of clean gauze and ensure that they are well spread out ov
38、er the whole surface area.Dry in a ventilated oven (5.8) at 70 C 5 C for 5 h. Using a balance (5.9), weigh the container and dried crumbs. Record the mass to 0,1 g.Return the container to the oven for a further 1 h and re-weigh. Continue to dry in the oven for 1 h periods until the loss in mass betw
39、een successive weightings is less than 0,5 g.6.3 Carboxylated (X-SBR and X-NBR) latices6.3.1 If it is not known whether or not the latex contains an antioxidant, transfer a portion of the test sample containing approximately 100 g of dry polymer to a clean, dry beaker and add 10 cm3of the antioxidan
40、t emulsion (4.3). Stir well.6.3.2 Take a portion of latex containing approximately 100 g of dry polymer with antioxidant (see 6.3.1) in a 1 dm3beaker and add 500 cm3of water. Stir well. Proceed as described in 6.2.2, 6.2.3 and 6.2.4. ISO 2015 All rights reserved 3BS ISO 2028:2015ISO 2028:2015(E)6.4
41、Nitrile (NBR) latices6.4.1 If it is not known whether or not the latex contains an antioxidant, transfer a portion of the test sample containing approximately 100 g of dry polymer to a clean, dry beaker and add 10 cm3of the antioxidant emulsion (4.3). Stir well.6.4.2 Transfer 2 dm3of the diluted alu
42、minium sulfate solution (4.4) to a 5 dm3stainless-steel beaker (5.1) and raise the temperature to 65 C 5 C by passing in steam (see 5.5).Remove the steam injector and introduce the electric stirrer (5.3). Stir at approximately 105 rad/s (1 000 r/min) while adding, in a slow stream, a portion of the
43、latex containing approximately 100 g of dry polymer together with antioxidant (see 6.4.1).Continue stirring for a further 5 min, then proceed as described in 6.2.3 and 6.2.4.6.5 Concentrated latices (more than 55 % solids content)6.5.1 If it is not known whether or not the latex contains an antioxid
44、ant, transfer a 200 g portion of the test sample to a clean, dry beaker and add 10 cm3of the antioxidant emulsion (4.3). Stir until thoroughly mixed.6.5.2 Transfer 2 dm3of ethanol (4.5) into a 5 dm3stainless-steel beaker equipped with a magnetic stirrer (5.4). While stirring slowly, add, in a steady
45、 stream, 200 g 5 g of the latex containing antioxidant (see 6.5.1).Continue stirring until the latex has completely precipitated and the serum is clear. Continue as described in 6.2.3 and 6.2.4.7 ReportThe report shall include the following information:a) a reference to this International Standard,
46、i.e. ISO 2028;b) all details necessary for complete identification of the test sample;c) whether or not an antioxidant was added, and if so its identity;d) which method (i.e. 6.2, 6.3, 6.4 or 6.5) was used;e) any unusual features noted during the test;f) full details of any operation not included in
47、 this International Standard or in any of the International Standards to which reference is made, together with any operation regarded as optional;g) the date of the test.4 ISO 2015 All rights reservedBS ISO 2028:2015BS ISO 2028:2015ISO 2028:2015(E) ISO 2015 All rights reservedICS 83.040.10Price bas
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