1、 STD*BSI BS b057: PT 3: SEC 3.25-ENGL 1797 H lb24bb7 DI353481 510 9 BS 6057 : Part 3 : Section 3.25 : 1997 IS0 13773 : 1997 BRITISH STANDARD Rubber latices Part 3. Methods of test Section 3.25 Determination of alkalinity for polychloroprene latex ICs 83.040.10 NO COPYING WITHOUT BSI PERMISSION EXCEP
2、T AS PERMITTED BY COPYRIGHT LAW STD*BSI BS b057: Amd. No. Date PT 3: Text affected Li57 BS 6057 : Part 3 : Section 3.25 : 1997 National foreword This British Standard reproduces verbatim IS0 13773 : 1997 and implements it as the UK nationai standard It partially supersedes BS 3397 : 1976 (Clause 6.1
3、). The UK participation in its preparation was entrusted to Technid Committee PRI/50, Natural and synthetic rubbers, which has the responsibility to: - aid enquirem to understand the te* - present to the responsible intemationaUEmpean committee any enquiries on the interpretation, or proposals for c
4、hange, 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 The British Standards which implement internatiord o
5、r 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 Fnd faciity of the BSI Standards Electronic Catalogue. Compliance with a British Standard does not of itself confe
6、r immunity from legal obligations. Summary of pages This document comprises a front cover, an inside bnt cover, the IS0 title page, page ii, pages 1 to 7 and a back cover. This British Standard, having been prepared under the direction of the Sector Board for Materiais and Chemicals, was published u
7、nder the authority of the Standards Board and comes inta effect on 15 November 1997 O BSI 1997 ISBN O 680 287% 7 BS 6057 : Part 3 : Section 3.25 : 1997 INTERNATIONAL STANDARD IS0 13773 First edition 1997-07-1 5 Rubber - Polychloroprene latex - Determination of alkalinity Caoutchouc - Latex de polych
8、lotvpdne - Dtemination de lalcalinit Reference number IS0 13773:1997(E) _ STD.BS1 BS b057: PT 3: SEC 3.25-ENGL 1997 9 Lb24bbS Ob53484 22T BS 6057 : Part 3 : Section 3.25 : 1997 Foreword IS0 (the International Organization for Standardization) is a worldwide federation of national standards bodies (I
9、S0 member bodies). The work of preparing International Standards is normally carried out through IS0 technical committees. Each member body interested in a subject for which a technical cornmittee has been established has the rigM to be represented on that committee. International organizations, gov
10、ernmental and non-governmental, in liaison with ISO, also take part in the work. IS0 collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Draft Intemational Standards adopted by the technical committees are circulated to th
11、e 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 13773 was prepared by Technical Committee ISOflC 45, Rubber and rubber products, Subcommittee SC 3, Raw matethls (including latex) for
12、 use in the rubber industry. Annexes A and B of this Intemational Standard are for information only. STD-BSI BS 6057: PT 3: SEC 3-25-ENGL 1797 D Lb24bb7 Ob53485 Ibb BS 6057 : Part 3 : Section 3.25 : 1997 Rubber - Polychloroprene latex - Determination of alkalinity WARNING - Persons using this Intern
13、ational Standard should be familiar with normal laboratory practice. This standard does not purport to address all of ths 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 nati
14、onal regulatory conditions. 1 scope This Intemational Standard specifies a method for the determination of the alkalinity of polychloroprene latex prepared by the polymerization of chloroprene in an alkaline emulsion. It is not suitable for polychloroprene latex prepared in a non-ionic emulsion, for
15、 natural rubber latex concentrate nor necessarily for synthetic tubber latices other than polychloroprene. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this Intemational Standard. All standards are subject to revisi
16、on, and parties to agreements based on this Intemational Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and IS0 maintain registers of currently valid Intemational Standards. IS0 123: 1985, Rubber latex - Sa
17、mpling. vi * IS0 976:1996, Rubber and plastics - Polymer dispersions and rubber latices - Detemination of pH. IS0 3696:1987, Water for analyiical laboratory use - Specification and test methods. 3 Principle A test portion of the latex is titrated electrometncally against hydrochloric acid to the sec
18、ond point of inflexion of the titration curve (pH in the range 4 to 5). The alkalinity is calculated from the amount of acid required. The alkalinity is commonly expressed as its two component parts in practice, .e. the amount of acid required to the first point of inflexion (pH in the range 10 to 1
19、1) which measures the amount of free alkali (the alkaline reserve) and the amount of additional acid required to the second point of inflexion which is a measure of the amount of saponified anionic organic surfactants in the latex, usually refered to as the “delta titre“. NOTE -When using a pH-meter
20、 to control the titration, it was formerly the practice to define the points of inflexion as pH 103 and 43. However since these do not always correspond to the points of inflexion the results obtained would be approximate. The results are expressed in millimoles of hydrochloric acid per 100 g of lat
21、ex. 4 Reagents For the analysis, use only reagents of recognized analytical grade and only distilled water free of dissolved carbon dioxide, or water of equivalent purity (grade 3 as defined in IS0 3696). 1 - STD-BSI BS b057: PT 3: SEC 3.25-ENGL 1777 D 1b24bb7 Ob53iAb UT2 D BS 6057 : Part 3 : Sectio
22、n 3.25 : 1997 4.1 Stabilizer solution: a 10 % (mm) solution of a non-ionic stabilizer of the alkyl phenol polyethylene oxide condensate type. NOTE - The precise nature of the stabilizer is not critical provided that it imparts acid stability to the latex and does not intedere with the titration. 4.2
23、 Hydrochloric acid, standard volumetric solution, c(HCI) = 0,l mo1/dm3. 5 Apparatus Standard laboratory apparatus, plus the following: 5.1 Automatic potentiometric titrator, fitted with an automatic burette and capable of delivering a volume of up to 50 cm. NOTE - It is permissible to use a manually
24、 operated 50 cm burette. In this case, it is desirable to make a preliminary assessment of the approximate end-points. 5.2 Combined pHsleetrode, with built-in glass electrode, suitable for use with solutions up to pH 14,O. 5.3 Magnetic or mechanical airrer, with variable speed and non-metallic paddl
25、e or magnetic bar. The motor shall be properly grounded to avoid interference. 6 Sampling Carry out sampling in accordance with one of the methods specified in IS0 123. NOTE - Unsealed samples of alkaline polychloroprene latex rapidly absorb carbon dioxide from the air. 7 Procedure Adjust the temper
26、ature of the reagents and test sample to 23 OC i 1 OC and calibrate the titrator in accordance with the manufactureh instructions or as described for pH-meters in IS0 976. Weigh, to the nearest 0,Ol g, an approximately 35 g test portion of the latex into a clean glass or plastic beaker of about 150
27、cm capacity. Insert and start the stirrer (5.3). Adjust the speed of the stirrer to obtain a small vortex at the surface of the liquid and slowly add 10 cm3 of the stabilizer solution (4.1) from a pipette. Insert the electrode (5.2) and the reagent discharge tip of the titrator. If there are signs o
28、f shock or coagulation on adding the stabilizer, dilute it with an equal volume of water before addition. a Start the titration for an automatic controlled addition of up to 50 cma of hydrochloric acid (4.2) where the volume increment and addition speed are based on the pH change. Record the volumes
29、 of acid V, and V, measured at the first and second inflexion points of the titration curve (approximately pH 10,5 and 43, respectively). Record the precise pH at the points of inflexion. If a manually operated burette is used (see note to 5.1), it is desirable to carry out a preliminary titration t
30、o give an approximate indication of the end-points. In subsequent titrations, add the hydrochloric acid in small increments through the range of the point of inflection. If there are indications of coagulation during the determination, repeat the procedure but using 20 cms of stabilizer solution. 2
31、STD-BSI BS b057: PT 3: SEC 3-25-ENGL 1977 = Lb24bb7 Ob53487 T37 BS 6057 : Part 3 : Section 3.25 : 1997 Repeat the determination using a fresh test portion of latex. If the calculated figures for the alkalinity differ by more than 0,02 mmol, carry oui the determination again using two fresh test port
32、ions. 8 Expression of results 8.1 Set the calculation parameters of the automatic titrator so as to obtain the alkaline resetve AR of the latex, expressed in millimoles of hydrochloric acid per 100 g of latex, using the equation: AR=-x100 CV, m where c is the actual concentration of the hydrochloric
33、 acid, expressed in moles of HCI per cubic decimetre; V, is the volume, in cubic centimetres, of hydrochloric acid required to reach the first end-point; m is the mass, in grams, of the test portion. 8.2 Calculate the delta titre AT of the latex, expressed in millimoles of hydrochloric acid per 100
34、g of latex, as follows: - V, is the volume, in cubic centimetres, of hydrochloric acid required to reach the second end-point; - * * rn c, V, and m are as defined in 8.1. 8.3 Calculate the alkalinity A, of the latex, expressed in millimoles of hydrochloric acid per 100 g of latex, as follows: A=AR+A
35、T where AR and AT are as defined in 8.1 and 8.2. 9 Testreport The test report shall include the following particulars: a) a reference to this International Standard; b) all details necessary for identification of the sample; c) the alkalinity of the latex, expressed to the nearest Oll mmol; d) the a
36、lkaline resewe and the delta titre of the latex, expressed to the nearest Oll mmol of hydrochloric acid per 100 g of latex; e) the pH recorded at the first and second points of inflexion; 9 the amount of stabilizer solution used; 3 STD-BSI BS b057: PT 3: SEC 3.25-ENGL 1777 Lb2Libb7 Ob53qBB 975 BS 60
37、67 : Part 3 : Section 3.25 : 1997 g) details of any unusual features noted during the determination; h) details of any operation not included in this International Standard or in the International Standards to which reference is made, as well as any operation regarded as optional; i) the date and pl
38、ace of the test. 4 STD-BSI BS bD57: PT 3: SEC 3-25-ENGL 1997 1b24bb9 Ob53489 BOL BS 6057 : Part 3 : Section 3.25 : 1997 Annex A (informative) Precision of the test method With accurate operation and control, it is possible to attain the following precision: A.l Repeatability Within the range I 0,02
39、mmol. A.2 Reproducibility Not established. NOTE -The work carried out to generate the precision data was initiated before the publication of ISO/TR 9272:1986, Rubber and rubber products - Determination of precision for test merhod standads. Consequently, the data are not expressed in the format reco
40、mmended by this Technical Report. 5 STD-BSI BS b057: PT 3: SEC 3.25-ENGL 1977 = LbZibb9 Ob53490 523 W BS 6057 : Part 3 : Section 3.25 : 1997 Annex B (informative) Example of the variation in pH during a titration Volume cm 0100 1,71 2,57 3,OO 3,86 4,86 5986 6,86 7,86 833 9154 1 0,09 10s 10,86 11,14
41、11,37 11,58 1 1,79 12,02 1227 12s 12,95 13,40 13,97 14,69 1559 16.59 17.59 1839 1939 20,59 21,59 2259 2339 24,59 2539 26.59 2739 28,29 2939 30,59 31,59 3239 3339 3459 35,59 36,49 3729 37,94 38,a Signal PH 12,603 1231 1 12,458 12,429 12,369 12,293 12,208 12,108 11,988 11,842 11,703 11,564 11,421 11,2
42、86 11,148 11,018 10,891 10,766 10,634 10,507 10,372 10,236 10,099 9,960 9,819 9,681 9,558 9,456 9,368 9,290 9,217 9,150 9,087 9,023 8,961 8,899 8,836 8,770 8,702 8,630 8,473 8,381 8,281 8,168 8,035 7,899 7,758 7,626 7,492 8,556 Signal change APH 0,OOO 0,092 0,053 0,029 0,060 0,076 0,085 0,100 0,120
43、0,146 0,139 0,139 0,143 0,135 0,138 O, 130 0,127 0,125 0,132 0,127 0,135 0,136 0,137 0,139 0,141 0,138 0,123 0,102 0,088 0,078 0,073 0,067 0,063 0,064 0,062 0,062 0,063 0,066 0,068 0,072 0,074 0,083 0,092 0,100 0,113 0,133 0,136 0,141 0,132 0,134 Difference ApWcm 05000 0,054 0,062 0,067 0,070 0,076
44、0,085 0,100 0,120 0,151 0,196 0,253 0,325 0,409 0,493 0,565 0,605 0,595 0,574 0,508 0,435 0,368 0,304 0,244 0,196 O, 153 0,123 0,102 0,088 0,078 0,073 0,067 0,063 0,064 0,062 0,062 0,063 0,066 0,097 0,055 0,074 0,083 0,092 Oll O0 0,113 0,133 0,151 0,176 0,203 0,220 6 STD.BS1 BS b057: PT 3: SEC 3-25-
45、ENGL 1777 m 1bZLibb7 Ob53471 4bT BS 6057 : Part 3 : Section 3.25 : 1997 39,lO 3937 40,Ol 40,41 40,96 41,37 41,78 42,20 42,62 43,05 434 43,91 44,35 44,79 45,24 45,69 46,15 46,61 47,08 4735 48,03 48,75 49,68 50,oo o,= 0,47 0,44 0,40 0,55 0.41 0,41 0,42 0,42 0,43 0,43 0,43 OS44 0.44 0,45 0,45 0,46 0,46
46、 0,47 0,47 0,48 0,72 0,93 0,32 7,351 7,219 7,073 6,956 6,775 6,626 6,469 6,303 6,130 5,934 5,700 5,402 4,987 4,504 4,076 3,739 3,454 3,216 3,017 2,860 2,735 2,591 2,450 2,411 0,141 0,132 0,146 0,117 0,181 0,149 0,157 0,166 0,173 0,196 0,234 0,298 0,415 0,483 0,428 0,337 0,285 0,238 0,199 0,157 0,125
47、 0,144 0,141 0,039 0,256 0,281 0,332 0,293 0,329 0,363 0,383 0,395 0,412 0,456 0,544 0,693 0,943 1,098 0,951 0,749 0,620 0,517 0,423 0,334 0,260 0,200 0,152 0,122 Figure 8.1 - Example of titration and derivative curves 7 SEC 3 25-ENGL BS 6057 : Part 3 : Section 3.25 : 1997 IS0 13773 : 1997 BSI 389 C
48、hiswick High Road London w4 4AL BSI - British Standards Institution BSI is the independent national body responsible for preparing British standards. It presents the UK view on standards in Europe and at the intemational level. It is incorporated by Royal Charter. Contract requirements A British Sta
49、ndard does not purport to include all the necessary provisions of a conimct Users of British Standards are responsible for their correct application. Revisions British Standards are updated by amendment or revicion. Users of British Standards should make sure that they possess the latest amendments or editions. It is the constant aim of BSI to improve the quality of our products and services. We would be grateful if anyone finding an inaccuracy or ambiguity while using this British Standard would inform the Secretary of the responsible techn
