1、BRITISH STANDARD Plastics - Organic-perester crosslinking agents for unsaturat ed-pol yest er thermosetting materials - Determination of active-oxygen content ICs 83.040.30 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGm LAW BS IS0 15038:1999 BS IS0 16038:1999 been prepared under t
2、he direction of the Sector Amd.No. Committee for Materials and Chemicals, was published under the authority of the Standards Committee and comes into effect on 15 September 1999 0 BSI 09-1999 National foreword Date Comments This British Standard reproduces verbatim IS0 15038:1999 and implements it a
3、s the K national standard. The UK participation in its preparation was entrusted to Technical Committee PRY42, Fibre reinforced thermosetting plastics and prepregs, which has the responsibility to: - aid enquirem to understand the text; - present to the responsible internationalEuropean committee an
4、y enquiries on the interpretation, or proposals for change, and keep the UK interests informed - monitor related international and European developments and promulgate them in the UK. A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references
5、The British Standards which implement international or European publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” faciiity of the BSI Standards Electronic Catalogue.
6、A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises
7、a front cover, an inside front cover, the IS0 title page, page ii, pages 1 to 7 and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued. ISBN O 680 32892 9 i NTERNATIONAL STAN DARD IS0 15038 First diion 1999-06-01 Plastics - Organic-perester
8、crosslinking agents for unsaturated-polyester thermosetting materials - Determination of active-oxygen content Plastiques -Agents de t6ticuation base de peresters organiques pour matriaux thermodurcissables base de polyesters non satuds - Dtemination de ia teneur en oxygne actif Reference number IS0
9、 15038: 1999( E) STD.BSI BS IS0 l503d-ENGL 1977 W lb2Libb Obll248 858 m BS IS0 16038:1999 Foreword IS0 (the Intemational Organization for Standardization) is a worldwide federation of national standards bodies (IS0 member bodies). The work of preparing International Standards is normally carried out
10、 through IS0 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 non-governmental, in liaison with ISO, also take part in the work. IS0 col
11、laborates closeiy with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISOAEC Directives, Part 3. Draft Intemational Standards adopted by the technical committees are
12、 circulated to the member bodies for voting. Publication as an Intemational Standard requires approval by at least 75 % of the member bodies casting a vote. Intemational Standard IS0 15038 was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 12, Themsetting materials. Annex A for
13、ms a normative part of this Intemational Standard. ii STD.BS1 BS IS0 15038-ENGL 1999 lb24bb9 OB11249 794 B BS IS0 16038:1999 tert-8utyIP-ethylperhexanoate isoPropyl fert-butylperoxy carbonate Plastics - Organic-perester crosslinking agents for unsaturated-polyester thermosetting materials - Determin
14、ation of active-oxygen content 216,3 176,2 WARNING - This International Standard involves the handling of dangerous products such as peroxides. lhe wearing of safety glasses is therefore essential throughout the test. tefiAmy1 perbenzoate red-Butyl 3,5,5-trimethylperhexanoate 1 scope This Intemation
15、al Standard specifies a method of determining the total active-oxygen content of organic peresters. It applies to those peresters used to initiate crosslinking of unsaturated-polyester thermosets. The peresters most widely used in the crosslinking of unsaturated-polyester resins are given in Table 1
16、. 208,3 230,4 Table 1 - Main types of organic prester Perester 1 Molecular mass tert-Butyl perbenzoate 1 194,2 - tert-Amyl2-ethylperhexanoate I 230,3 Butyl peresters may contain traces of tert-butyl hydroperoxide (TBHP), the active oxygen in which can be determined separately from that in the perest
17、er itself (see annex A). The aciive-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 Intemational Standard. For dated references,
18、subsequent 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
19、, the latest edition of the normative document referred to applies. Members of IS0 and IEC maintain registers of currently valid International Standards. IS0 385-1 :1984, Laboratory glassware - Burettes - Part 7: General requirements. IS0 648:1977, Laboratory glassware - One-mark pipettes. IS0 3696:
20、1987, Water for analytical laboratory use - Specification and test mefhods. 1 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 crosslinkin
21、g of organic compounds which have a C=C double 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 ter?-butyl hydroperoxide (TBHP) as an example: CH3 I C“ 3 I NOTE The comp
22、ound obtained has the properties of a peroxide group -0-O- and those of an organic-acid group R-C-O- O II 4 Principle A test portion of the perester is reacted with potassium iodide in a propanoVacetic acid medium in the presence of copper(l1) chloride. The iodine released is then determined quantit
23、atively using a standardized sodium thiosulfate solution. CH3 I CH3 I R-C-O-O-C-CH, + 21 + HZO -C I2 + R-C-O- + CH,-C-OH + OH- II I II I O CH3 O CH3 l2 + 2NazS2O3 - 2Nal+ Na,S,O, 5 Reagents 5.1 Water, grade 3 as defined in IS0 3936, for use in preparing all the solutions listed below and in all othe
24、r operations. 5.2 5.3 5.4 5.5 5.6 5.7 2 Sodium thiosulfate, standardized solution, c(Na2S,0,) = 0,l mol/. Glacial acetic acid. Isopropanol, analytical grade. Copper(Jl) chloride, 1 O gA aqueous solution (shelf life 6 months). Potassium iodide, saturated solution freshly prepared from 100 g of KI and
25、 100 ml of water (shelf life 1 day). Nitrogen or carbon dioxide, purity a 99,9 %. STD-BSI BS IS0 L5038-ENGL 1999 Lb2LcbbS OBLL25L 342 BS IS0 16038:1999 6 Apparatus 6.1 Conical flask, capacity 200 ml, with a 29/32 ground-glass neck and stopper. 6.2 Analytical balance, accurate to O, 1 mg. 6.3 Weighin
26、g tube, glass dish or tared syringe. 6.4 Onemark pipettes, capacity 1 ml and 5 ml, as specified in IS0 648. 6.5 Burette, capacity 50 ml, as specified in IS0 385-1. 6.6 Graduated test tubes, capacity 50 rnl and 20 ml. 6.7 Magnetic stirrer. 7 Procedure Pour 40 ml of isopropanol (5.4) and 15 ml of acet
27、ic acid (5.3) into the conical flask (6.1). Pass a gentle flow (approximately 150 mllmin) 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 ml of copper
28、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,l mg, approximately 2 mmol of the perester to be analysed. Place the test portion in the conical flask, stopper the flask and stir until the t
29、est 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 be used pro
30、vided 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. Carfy out a blank determination under the same conditions but omitting the test portion. Repeat the procedure
31、 on a second test portion. 8 Expression of results 8.1 Total activeoxygen content The total active-oxygen content (AO)T, in mass %, is calculated using the equation (V, -V)X c x 0,8 m = 3 - STD-BSI BS IS0 25036-ENGL 2199 lb2Libb9 0822252 239 BS IS0 16038:1999 where V, is the volume, in millilitres,
32、of sodium thiosulfate solution (5.2) used to titrate the test portion; V, is the volume, in millilitres, of the sodium thiosulfate solution used to titrate the blank; c is the concentration, in moles/litre, of the sodium thiosulfate solution; m is the mass, in grams, of the test portion. 8.2 Pereste
33、r content In the absence of any traces of red-butyl hydroperoxide (TBHP), the perester 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 conce med. (AO), x M 16 Perester content = where M is the molecul
34、ar mass of the perester. In the case of a diperester, the ratio M/1 6 is replaced by M/32. 8.3 Correction for TBHP If there are traces of TBHP, the active-oxygen content of the TBHP alone, (AO), can be determined by the method given in annex A. The activeaygen content of the perester alone, (AO)pER,
35、 is obtained by subtraction: (WPER = (WT - (WTBHP The perester content of the sample is then calculated as in 8.2, using (AO), 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 pereste
36、r sample, the precision of this method has been determined to be as follows: For an active-oxygen content of 1 O YO, S, = 0,017, r = 0,05, $R = 0,035 and R = 0,l where s, is the within-laboratory standard deviation; sR is the between-laboratory standard deviation; r is the repeatability, .e. the val
37、ue below which the difference between two results, each the mean of duplicates, 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; R is the reproducibility, .e. the value below which
38、the difference between two results, each the mean of duplicates, obtained on identical material by operators in different laboratories within a short interval of time using the standardized test method would be expected to lie. 4 STD-BSI BS IS0 15038-ENGL 1999 W lb2iibb9 U811253 115 BS IS0 16038:199
39、9 10 Test report The test report shall include the following information: a) a reference to this Intemational Standard; b) all details necessary for complete identification of the material tested (type, origin, trade designation, etc.); c) the individual results and their average; d) the date of the
40、 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. 5 STD-BSI BS IS0 L5038-ENGL 1779 m lb24bb7 OALL25Li 052 W BS IS0 160381999 Annex A (normative) Active-oxygen content of fetf-butyl
41、 hydroperoxide A.1 Scope This annex specifies a method for the determination of the active-oxygen content of red-butyl hydroperoxide (TBHP) in a tert-butyl perester. The method is not aplicable if the product also contains other hydroperoxides, peracids or ketone peroxides. A.2 Principle The TBHP is
42、 reduced in a toluene-methanol medium using SO2 dissolved in a pyridine-methanol mixture. The excess SO, is titrated with iodine solution. CH3 I CH3 I H2S03 + H20 + l2 - SO:- + 21- + 4” A.3 Reagents A.3.1 Water, grade 3 as defined in IS0 3696, for use in preparing all the solutions listed below and
43、in all other operations. A.3.2 Toluene, analytical grade. A.3.3 Iodine, aqueous solution, c(12) = 0,05 mol/l (shelf life 1 month). Dissolve approximately 12,7 g of iodine in 40 g of 500 gil potassium iodide solution and make up to 1000 ml with water (A.3.1). A.3.4 Methanol, analytical grade. A.3.5 P
44、yridine, analytical grade, 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 (S0,),.0,05 mol solution in a 1O:I methanol-pyridine mixture (shelf life 2 weeks). There are two possible
45、ways of preparing this solution: 6 STD.BS1 BS IS0 L503-ENGL 1999 m lb24bb 08LL255 T98 m BS IS0 15038:1999 - Method 1: carefully add 1,5 ml of liquid SO, 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 Fische
46、r A solution into a 1 O00 ml volumetric flask and make up to the mark with a 1O:l mixture of methanol (A.3.4) and pyridine (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 m
47、l. A.4.3 Volumetric flask, capacity 1 O00 ml. A.4.4 Graduated test tubes, capacity 25 ml and 50 ml. A.4.5 Burette, capacity 25 ml, graduated at 0,05 ml intervals. AS Procedure Weigh, to the nearest 0,l mg, approximately 3 g of the perester to be analysed into the conical flask (A.4.1) (choose the si
48、ze of the test portion so that at least half the SO, used for the reduction is subsequently titrated by the iodine solution). 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 moVI SO, solution (A.3.6) and stir well. Add 50 ml of methanol (A
49、.3.4), and then titrate with 0.05 moIA 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 (Vd - V, ) x c x 1,6 (AO)lBHP = m where V, is the volume, in millilitres, of iodine solution (A.3.3) used to titrate the test portion; V, is the volume, in millilitres, of the iodine solution used to titrate the blank; c is the concentration, in moles/litre, of the iodine soluti
