ISO INTERNATIONAL STANDARD 9702 First edition 1996-12-01 Plastics Amine epoxide hardeners Determination of primary, secondary and tertiary amine group nitrogen content PlastiquesDurcisseurs pourreésines époxyDétermination dela teneur en azote des groupes amine primaire, secondaire, tertiaire This material is reproduced from Iso documents under International Organization for Standardization (IsO) Copyright License number IHS/icc/1996. Not for resale. No part of these ISo documents may be reproduced in any form, electronic retrieval system or otherwise, except as aliowed in the copyright law of the country of use, or with the prior written consent of IsO (Case postale 56, 1211 Geneva 20, Switzerland, Fax +41 22 7341079),IHsortheIsoLicensor'smembers. ISO Reference number ISO 9702:1996(E) No reproduction c Not for Resale IS0 9702:1996(E) 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 committees. Each member body interested in a subject for which a technical committee has been established has the right to be 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. 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 bodies casting a vote international Standard iSO 9702 was prepared by Technical Committee IsO/TC 61, Plastics, Subcommittee Sc 12, Thermosetting materials. CISO1996 Alt rights reserved. Unless otherwise specified, no part of this publication may 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 OrganizationforStandardization CasePostale56·CH-1211Geneve20·Switzerland Printed in Switzerland i ense from IHS Not for Resale INTERNATIONAL STANDARD ISO ISO9702:1996(E) Plastics - Amine epoxide hardeners - Determination of primary, secondary and tertiary amine group nitrogen content 1 Scope RNH2 + (CH3CO)2O →) This International Standard specifies a method for the RNHCOCH3 + CH3COOH determination of the primary, secondary and tertiary amine group nitrogen content of aliphatic or aromatic (RR')NH + (CH3CO)2O - amine hardeners for epoxy resins. (RR')NCOCH3 + CH3COOH 2 Principle The tertiary amine group alkalinity is determined by potentiometric titration against hydrobromic or per- 2.1 Aliphatic amines chloric acid in glacial acetic acid/acetic anhydride, as described by the following reaction: 2.1.1 Determination of total amine group nitrogen content (XT) (RR'R")NH + H+ →(RR'R")NH+ The total alkalinity is determined by potentiometric The results are expressed as percentage nitrogen. titration against hydrobromic or perchloric acid in glacial acetic acid, as described by the following reactions: 2.1.3 Determination of primary amine group nitrogen content (XL1) RNH2 + H+ -→ RNH3+ (RR'NH + H+→(RR')NH2+ The primary amine groups are reacted with a measured excess of 2,4-pentanedione (acetylacetone) (RR'R")N + H+ -→ (RR'R")NH+ in N,N-di-methylformamide to form imines, as described by the following reaction: The results are expressed as percentage nitrogen. RNH2 + CH3COCH2COCH3 -→ NOTE 1 Perchloric acid is not suitable for use with amine hardeners such as N-aminoethylpiperazine. CH3CNRCH2COCH3 + H20 2.1.2 Determination of tertiary amine group The excess acetylacetone is determined by poten nitrogen content (X3) tiometric titration against potassium hydroxide (the reaction products of acetylacetone and primary amine The primary and secondary amine groups are groups are neutral under these conditions). converted into amide groups