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1、A Reference number ISO 15038:1999(E) INTERNATIONAL STANDARD ISO 15038 First edition 1999-06-01 Plastics Organic-perester crosslinking agents for unsaturated-polyester thermosetting materials Determination of active-oxygen content Plastiques Agents de rticulation base de peresters organiques pour mat
2、riaux thermodurcissables base de polyesters non saturs Dtermination de la teneur en oxygne actif Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/24/2007 22:06:57 MDTNo reproduction or ne
3、tworking permitted without license from IHS -,-,- ISO 15038:1999(E) ISO 1999 All 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 w
4、riting from the publisher. International Organization for Standardization Case postale 56 CH-1211 Genve 20 Switzerland Internetisoiso.ch Printed in Switzerland ii Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodi
5、es). 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 represented on that committee. International organizations, governmental and
6、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. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, P
7、art 3. 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 15038 was prepared by Technical Committ
8、ee ISO/TC 61, Plastics, Subcommittee SC 12, Thermosetting materials. Annex A forms a normative part of this International Standard. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/24/200
9、7 22:06:57 MDTNo reproduction or networking permitted without license from IHS -,-,- INTERNATIONAL STANDARD ISOISO 15038:1999(E) 1 Plastics Organic-perester crosslinking agents for unsaturated-polyester thermosetting materials Determination of active-oxygen content WARNING This International Standar
10、d involves the handling of dangerous products such as peroxides. The wearing of safety glasses is therefore essential throughout the test. 1 Scope This International Standard specifies a method of determining the total active-oxygen content of organic peresters. It applies to those peresters used to
11、 initiate crosslinking of unsaturated-polyester thermosets. The peresters most widely used in the crosslinking of unsaturated-polyester resins are given in Table 1. Table 1 Main types of organic perester PeresterMolecular mass tert-Butyl perbenzoate194,2 tert-Butyl 2-ethylperhexanoate216,3 iso-Propy
12、l tert-butylperoxy carbonate176,2 tert-Amyl 2-ethylperhexanoate230,3 tert-Amyl perbenzoate208,3 tert-Butyl 3,5,5-trimethylperhexanoate230,4 Butyl peresters may contain traces of tert-butyl hydroperoxide (TBHP), the active oxygen in which can be determined separately from that in the perester itself
13、(see annex A). The active-oxygen content of the perester alone can then be obtained by subtraction. 2 Normative references The following normative documents contain provisions which, through reference in this text, constitute provisions of this International Standard. For dated references, subsequen
14、t amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the lat
15、est edition of the normative document referred to applies. Members of ISO and IEC maintain registers of currently valid International Standards. ISO 385-1:1984, Laboratory glassware Burettes Part 1: General requirements. ISO 648:1977, Laboratory glassware One-mark pipettes. ISO 3696:1987, Water for
16、analytical laboratory use Specification and test methods. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/24/2007 22:06:57 MDTNo reproduction or networking permitted without license from
17、 IHS -,-,- ISO 15038:1999(E) ISO 2 3 Terms and definitions For the purposes of this International Standard, the following definitions apply: 3.1 active oxygen of an organic perester oxygen, liberated by an organic perester, capable of initiating crosslinking of organic compounds which have a C=C dou
18、ble bond such as unsaturated-polyester resins 3.2 perester a peroxide obtained by the reaction of an acid chloride with a hydroperoxide in accordance with the following equation using tert-butyl hydroperoxide (TBHP) as an example: NOTE The compound obtained has the properties of a peroxide group O O
19、 and those of an organic-acid group 4 Principle A test portion of the perester is reacted with potassium iodide in a propanol/acetic acid medium in the presence of copper(II) chloride. The iodine released is then determined quantitatively using a standardized sodium thiosulfate solution. 5 Reagents
20、5.1 Water, grade 3 as defined in ISO 3936, for use in preparing all the solutions listed below and in all other operations. 5.2 Sodium thiosulfate, standardized solution, c(Na2S2O3) = 0,1 mol/l. 5.3 Glacial acetic acid. 5.4 Isopropanol, analytical grade. 5.5 Copper(II) chloride, 10 g/l aqueous solut
21、ion (shelf life 6 months). 5.6 Potassium iodide, saturated solution freshly prepared from 100 g of KI and 100 ml of water (shelf life 1 day). 5.7 Nitrogen or carbon dioxide, purity 99,9 %. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA T
22、echnical Standards 1/9972545001 Not for Resale, 04/24/2007 22:06:57 MDTNo reproduction or networking permitted without license from IHS -,-,- ISOISO 15038:1999(E) 3 6 Apparatus 6.1 Conical flask, capacity 200 ml, with a 29/32 ground-glass neck and stopper. 6.2 Analytical balance, accurate to 0,1 mg.
23、 6.3 Weighing tube, glass dish or tared syringe. 6.4 One-mark pipettes, capacity 1 ml and 5 ml, as specified in ISO 648. 6.5 Burette, capacity 50 ml, as specified in ISO 385-1. 6.6 Graduated test tubes, capacity 50 ml and 20 ml. 6.7 Magnetic stirrer. 7 Procedure Pour 40 ml of isopropanol (5.4) and 1
24、5 ml of acetic acid (5.3) into the conical flask (6.1). Pass a gentle flow (approximately 150 ml/min) of nitrogen or carbon dioxide (5.7) through the flask above the surface of the liquid. Maintain this gas flow until the conical flask is stoppered (see below). Using a pipette (6.4), add exactly 1 m
25、l of copper chloride solution (5.5). Stir gently on the magnetic stirrer (6.7) to homogenize. Using a weighing tube, dish or tared syringe (6.3), weigh, to the nearest 0,1 mg, approximately 2 mmol of the perester to be analysed. Place the test portion in the conical flask, stopper the flask and stir
26、 until the test portion is dissolved. Using a pipette (6.4), add 4 ml of potassium iodide solution (5.6). Re-stopper the conical flask and stir again. Allow to stand away from light for 30 min at ambient temperature (for certain peresters, this length of time is not necessary, and a shorter time may
27、 be used provided it can be demonstrated that the results are not affected). Add 50 ml of water (5.1) and titrate with sodium thiosulfate solution (5.2) until the solution becomes completely colourless. Carry out a blank determination under the same conditions but omitting the test portion. Repeat t
28、he procedure on a second test portion. 8 Expression of results 8.1 Total active-oxygen content The total active-oxygen content (AO)T, in mass %, is calculated using the equation (AO) ()0,8 T = VVc m 12 Copyright International Organization for Standardization Provided by IHS under license with ISO Li
29、censee=NASA Technical Standards 1/9972545001 Not for Resale, 04/24/2007 22:06:57 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 15038:1999(E) ISO 4 where V1is the volume, in millilitres, of sodium thiosulfate solution (5.2) used to titrate the test portion; V2is the vo
30、lume, in millilitres, of the sodium thiosulfate solution used to titrate the blank; cis the concentration, in moles/litre, of the sodium thiosulfate solution; mis the mass, in grams, of the test portion. 8.2 Perester content In the absence of any traces of tert-butyl hydroperoxide (TBHP), the perest
31、er content, in mass %, of the sample is calculated from the active-oxygen content (AO)T by simple proportion, using the molecular mass of the perester concerned. Perester content = (AO)T M 16 where M is the molecular mass of the perester. In the case of a diperester, the ratio M/16 is replaced by M/
32、32. 8.3 Correction for TBHP If there are traces of TBHP, the active-oxygen content of the TBHP alone, (AO)TBHP, can be determined by the method given in annex A. The active-oxygen content of the perester alone, (AO)PER, is obtained by subtraction: (AO)PER = (AO)T (AO)TBHP The perester content of the
33、 sample is then calculated as in 8.2, using (AO)PER instead of (AO)T. 9 Precision Following a round-robin test organized in France involving four laboratories, each of which carried out five determinations on the same perester sample, the precision of this method has been determined to be as follows
34、: For an active-oxygen content of 10 %, sr = 0,017, r = 0,05, sR = 0,035 and R = 0,1 where sris the within-laboratory standard deviation; sRis the between-laboratory standard deviation; ris the repeatability, i.e. the value below which the difference between two results, each the mean of duplicates,
35、 obtained on identical material by the same operator in the same laboratory within a short interval of time using the standardized test method would be expected to lie; Ris the reproducibility, i.e. the value below which the difference between two results, each the mean of duplicates, obtained on id
36、entical material by operators in different laboratories within a short interval of time using the standardized test method would be expected to lie. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for
37、Resale, 04/24/2007 22:06:57 MDTNo reproduction or networking permitted without license from IHS -,-,- ISOISO 15038:1999(E) 5 10 Test report The test report shall include the following information: a) a reference to this International Standard; b) all details necessary for complete identification of
38、the material tested (type, origin, trade designation, etc.); c) the individual results and their average; d) the date of the determination; e) details of any operation not mentioned in this International Standard, as well as details of any incident likely to have had an effect on the results. Copyri
39、ght International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/24/2007 22:06:57 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 15038:1999(E) ISO 6 Annex A (normative) Active-ox
40、ygen content of tert-butyl hydroperoxide A.1 Scope This annex specifies a method for the determination of the active-oxygen content of tert-butyl hydroperoxide (TBHP) in a tert-butyl perester. The method is not aplicable if the product also contains other hydroperoxides, peracids or ketone peroxides
41、. A.2 Principle The TBHP is reduced in a toluene-methanol medium using SO2 dissolved in a pyridine-methanol mixture. The excess SO2 is titrated with iodine solution. A.3 Reagents A.3.1 Water, grade 3 as defined in ISO 3696, for use in preparing all the solutions listed below and in all other operati
42、ons. A.3.2 Toluene, analytical grade. A.3.3 Iodine, aqueous solution, c(I2) 0,05 mol/l (shelf life 1 month). Dissolve approximately 12,7 g of iodine in 40 g of 500 g/l potassium iodide solution and make up to 1000 ml with water (A.3.1). A.3.4 Methanol, analytical grade. A.3.5 Pyridine, analytical gr
43、ade. WARNING Pyridine is toxic. Avoid inhalation of vapour. Prevent contact with skin and eyes. Work under a fume hood or in a well ventilated area. A.3.6 Sulfur dioxide (SO2), 0,05 mol/l solution in a 10:1 methanol-pyridine mixture (shelf life 2 weeks). There are two possible ways of preparing this
44、 solution: Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/24/2007 22:06:57 MDTNo reproduction or networking permitted without license from IHS -,-,- ISOISO 15038:1999(E) 7 Method 1: car
45、efully add 1,5 ml of liquid SO2 to a mixture of 500 ml of methanol (A.3.4) and 50 ml of pyridine (A.3.5) with continuous stirring. Method 2: pour 25 ml of commercial Karl Fischer A solution into a 1000 ml volumetric flask and make up to the mark with a 10:1 mixture of methanol (A.3.4) and pyridine (
46、A.3.5). A.4 Apparatus In addition to the apparatus specified in clause 6, the following is required: A.4.1 Conical flask, capacity 200 ml. A.4.2 One-mark pipette, capacity 10 ml. A.4.3 Volumetric flask, capacity 1000 ml. A.4.4 Graduated test tubes, capacity 25 ml and 50 ml. A.4.5 Burette, capacity 2
47、5 ml, graduated at 0,05 ml intervals. A.5 Procedure Weigh, to the nearest 0,1 mg, approximately 3 g of the perester to be analysed into the conical flask (A.4.1) (choose the size of the test portion so that at least half the SO2 used for the reduction is subsequently titrated by the iodine solution)
48、. Add 20 ml of toluene (A.3.2) and homogenize by gentle stirring. Using the pipette (A.4.2), add 10 ml of 0,05 mol/l SO2 solution (A.3.6) and stir well. Add 50 ml of methanol (A.3.4), and then titrate with 0,05 mol/l iodine solution (A.3.3). Carry out a blank determination under the same conditions but omitting the test portion. A.6 Expression of results The active-oxygen content of the TBHP, (AO)TBHP, in mass %, is calculated using the equation (AO) ()1,6 TBHP = VVc m 4