1、BRITISH STANDARD Plastics - Ethylene/vinyl acetate copolymer (EVAC) thermoplastics - Determination of vinyl acetate content The European Standard EN IS0 8985: 1998 has the status of a British Standard ICs 83.080.20 BS EN IS0 8985:1998 NO COPYING WITHOUT BSI PERMISSION E - STD-BSI BS EN IS0 8785-ENGL
2、 1998 W Lb2Ybb7 0734670 335 direction of the Sector Amd.No. Committee for Materiais and Chemicals, was published under the authority of the Standards Committee and comes into effect on 15 December 1998 O BSI 1998 National foreword Date Text affected This British Standard is the English hguage versio
3、n of EN IS0 8985.1998. It is identical with IS0 8985:1998. The UK participation in its preparation was entrusted to Technical Committee PRI/32, Olefin plastics, which has the responsibility to: - aid enquirers to understand the text; - present to the responsible internationaVEuropm committee any enq
4、uiries on the interpretation, or proposais 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 Atten
5、tion is drawn to the fact that CEN and CENELEC standards normally include an annex which lists normative references to international publications with their corresponding European publications. The British Standards which implement international or European publications referred to in this document
6、may be found in the BSI Standards Catalogue under the section entitled international Standards Correspondence Index”, or by using the Find” facility of the BSI Standards Electronic Caalogue. A British Stana,rd does not purport to include all the necessary provisions of a contract Users of British St
7、andards 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 a front cover, an inside front cover, the EN IS0 title page, the EN IS0 foreword page, the IS0 title page, pag
8、e ii, pages 1 to 20, an inside back cover and a back cover. I l ISBN O 580 29832 9 I I EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN IS0 8985 March 1990 ICs 83.080.00 Descriptors: see IS0 document English version Plastics - Ethylene/vinyl acetate copolymer (EVAC) thermoplastics - Determinatio
9、n of vinyl acetate content (IS0 8985: 1998) Plastiques - CopolymBres Bthylndactate de vinyle (EVAC) thennoplactiques - Dosage de lactate de vinyie (IS0 89891998) This European Standard was approved by GEN on 15 February 1998. CEN members are bound to comply with the CEWCENELEC Internal Regulations w
10、hich stipulate the conditions for gMng this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CEN member. This European Sta
11、ndard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official versions. CEN members are the national sta
12、ndards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy. Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDEAON COMITE EUROPEEN DE NORMALISATION EUROPISCHES KOMITEE FO
13、R NORMUNG Central Secretariat: rue de Stassart, 36 E1050 Brussels CQ 1998 CEN All rights of exploitation in any form and by any means resewed worldwide for CEN national Members. Ref. No. EN IS0 8985:1998 E STD-BSI BS EN IS0 8985-ENGL 1998 - Lb24669 0734b92 EN IS0 898k1998 Foreword The text of the In
14、ternational Standard IS0 89851998 has been prepared by Technical committee ISOTTC 61 “Plastics“ in collaboration with Technical Committee CENTTC 249 “Plastics“, the secretariat of which is held by IBN. This European Standard shall be given the status of a national standard, either by publication of
15、an identical text or by endorsement, at the latest by September 1998, and conflicting national standards shall be withdrawn at the latest by September 1998. According to the CENICENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this
16、European Standard: Austria, Belgium, Czech-Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom. Endorsement notice The text of the International Standard IS0 89851998 was approved b
17、y CEN as a European Standard without any modification. STD-BSI BS EN IS0 8785-ENGL 1998 W 1b24bb9 0734693 044 EN IS0 8985:1998 INTERNATIONAL STANDARD IS0 8985 Second edition 1998-03-01 Plastics - Ethylene/vinyl acetate copolymer (EVAC) thermoplastics - Determination of vinyl acetate content Plastiqu
18、es - Copolymres fhy/ne/actate de vinyle (E VAC) thermoplastiques - Dosage de /actate de vinyle Reference number IS0 8985: 1998( E) Foreword IS0 (the International Organization for Standardization) is a worldwide federation of national standards bodies (IS0 member bodies). The work of preparing Inter
19、national Standards is normally carried out 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 wi
20、th ISO, also take part in the work. IS0 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 a
21、n International Standard requires approval by at least 75 % of the member bodies casting a vote. Intemational Standard IS0 8985 was prepared by Technical Committee ISOTTC 61, Plastics, Subcommittee SC 9, Thermoplastic materials. This second edition cancels and replaces the first edition (IS0 8985:19
22、89), which has been technically revised. Descrlptors: plastics, thermoplastic resins, copolymers, ethylene, vinyl acetate copolymers, chemical analysis, determination of content, vinyl acetate. i Plastics - EthyleneMnyl acetate copolymer (EVAC) thermoplastics - Determination of vinyl acetate content
23、 1 Scope This International Standard specifies two categories of method for the determination of the vinyl acetate (VAC) content of ethylenehinyl acetate (EVAC) copolymers, for use in the designation of such copolymers in accordance with IS0 4613-1: 1997. One category is referred to as “reference me
24、thods“, the other as “test methods“. Note - The abbreviation previously used for ethylenehinyl acetate copolymer (WAC) has been replaced by the abbreviation EVAC (see IS0 1043- 1 : 1997, Plastics - Symbols and abbreviated terms - Part I: Basic polymers and their special characteristics). The “refere
25、nce methods“ are used to calibrate the method used for the determination of the vinyl acetate content of ethylenelvinyl acetate copolymers. The “test methods“ are other methods which can be used for the determination if they are calibrated using one of the reference methods described in clause 3 pro
26、vided they show a certain permissible repeatability. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the editions indicated were valid. All standards are subject
27、 to revision, and parties to agreements based on this International 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 International Standards. IS0 46 13- 1 : 1993,
28、 Plastics - Ethylenehinyl acetate (ENAC) moulding and extrusion materials - Part I: Designation and specification. IS0 4799: 1978, Laboratory glassware - Condensers. STD.BSI BS EN IS0 8985-ENGL 1778 I1624669 0734676 853 EN IS0 8985:1998 3 Reference methods 3.1 Reference method 1: Hydrolysis and back
29、 titration 3.1.1 Principie A test portion is dissolved in xylene and the acetate groups are hydrolysed with alcoholic potassium hydroxide solution. An excess of sulfuric or hydrochloric acid is added. The acid is back titrated with a standard sodium hydroxide solution in the presence of phenophthale
30、in as indicator. 3.1.2 Reagents During the analysis, use only reagents of recognized analytical quality and distilled water or water of equivalent purity. 3.1.2.1 Xylene. 3.1.2.2 Sulfuric acid, approx. 5gA solution, or hydrochoric acid, approx. 3,7g/l solution. 3.1.2.3 Potassium hydroxide, approx. 5
31、,6gA ethanol solution. Dissolve 5,6g of solid potassium hydroxide (KOH) in 500ml of ethanol, make up to 1000m1, leave to settle until the next day and decant the clear part of the solution. 3.1.2.4 Sodium hydroxide, standard solution, c(Na0H) = 0,l molA. Note - The nomenclature (XXXX) is preferred t
32、o xxxx and used throughout, e.g. c(Na0H) = NaOH, when referring to concentrations. 3.1.2.5 Phenolphthalein, indicator solution. Dissolve 0,7g of phenolphthalein in 1oOml of ethanol. 3.13 Apparatus Standard laboratory apparatus, plus the following: 3.1.3.1 Burette, 50ml capacity, for the sodium hydro
33、xide solution (3.1.2.4). 3.1.3.2 Pipette, 3oml capacity, for the acid solution (3.1.2.2). 3.1.33 Pipette, 25ml capacity, for the potassium hydroxide solution (3.1.2.3). 3.1.3.4 Test tube, 5oml capacity, for the xylene (3.1.2.1). 3.1.3.5 Flask, up to 3ooml capacity, with stopper. 3.1.3.6 Dropping bot
34、tle, for the phenolphthalein indicator solution (3.1.2.5). 3.1.3.7 Reflux condenser, at least 5ooml long, in accordance with IS0 4799. 3.1.3.8 Heating equipment: sand bath, oil bath or heating jacket, adjustable to 200C. 2 3.1.3.9 Analytical balance, with an accuracy of O, lmg. 3.1.4 Procedure 3.1.4
35、.1 Determination 3.1.4.1.1 Weigh a quantity of dry polymer as shown in taule into the flask (3.1.3.5) to the nearest 0,lmg. The mass ofeach sample p-rticle shall be less than approx. 0,05g. Table 1 - Guide to the mass of the sample to be used I Assumed vinyl acetate content, w(VAC) I Approximate mas
36、s of test portion I 96 g; w(VAC) I: 10 1 10 w(VAC) I20 075 20 e w(VAC) I40 093 40 c w(VAC) 02 When analysing an unknown sample, first cany out a preliminary test under conditions which are valid for a copolymer containing 20% to 40% VAC. 3.1.4.1.2 Add 50ml of xylene (3.1.2.1) to the contents of the
37、flask and 25mi of potassium hydroxide (3.1.2.3), using the pipette (3.1.3.3). Heat the flask, topped with the reflux condenser (3.1.3.7), for 2 hours using the heating apparatus. After hydrolysis, remove the flask from the heating apparatus and allow to cool to ambient temperature. Add 30ml of sulfu
38、ric or hydrochloric acid (3.1.2.2), using the pipette (3.1.3.2), stopper the flask and shake vigorously. Add several drops of phenolphthalein solution (3.1.2.5) and titrate the excess acid with standard sodium hydroxide solution (3.1.2.4), shaking the flask during the titration. 3.1.4.2 Blank test C
39、any out a blank test in parallel with the determination, following the same procedure and using the same reagents but omitting the test portion. 3.1.5 Expression of results 3.1.5.1 The vinyl acetate content w(VAC), expressed as a percentage by mass, is given by the formula: 8,609(1 - V)C, w(VAC) = m
40、 where VI is the volume, in millilitres, of sodium hydroxide solution used for the determination; v2 is the volume, in millilitres, of sodium hydroxide solution used for the blank test; cl is the actual concentration, expressed in moles per litre, of the sodium hydroxide solution used for the titrat
41、ion; rn is the mass, in grams, of the test portion (see 3.1.4.1.1). STD-BSI ES EN IS0 8985-ENGL 1998 Lb24669 0734698 626 m EN IS0 8985:1998 3.1.5.2 Carry out two determinations. If the results differ by more than 1%, discard them and run the determinations again. Report the arithmetic mean of the tw
42、o determinations. 3.1.6 Test report The test report shall contain the following information: a) a reference to this International Standard and the method used; b) all details necessary for the complete identification of the sample; c) the result, expressed in accordance with 3.1.5.2. 3.2 Reference m
43、ethod 2: Saponification and potentiometric titration 3.2.1 Principle A test portion is dissolved in a mixture of xylene and hexan-1-01 and the acetate groups are hydrolysed with alcoholic potassium hydroxide solution. Acetone is added to prevent copolymer precipitation. The excess alkali is titrated
44、 with standard hydrochloric acid using a potentiometric titrimeter. 3.2.2 Reagents During analysis use only reagents of recognized analytical quality and distilled water or water of equivalent purity . 3.2.2.1 Xylene. 3.2.2.2 Hexan-1-01. 3.2.2.3 Potassium hydroxide, approx. 28g4 ethanolic solution.
45、3.2.2.4 Acetone. 3.2.2.5 Hydrochloric acid, standard solution, c(HC1) = 0,3moM. 3.2.2.6 Lithium chloride, 40gA ethanolic solution. 3.2.3 Apparatus Standard laboratory equipment, plus the following: 3.2.3.1 Potentiometric titrator, with a 1Oml capacity burette graduated every 0,02ml, a millivoltmeter
46、 or other suitable type of voltmeter, a glass measurement electrode, a silver/silver chloride reference electrode and a connecting bridge and beaker filled with an ethanolic solution of lithium chloride (3.2.2.6). Other types of potentiometric titrator may be used. 3.2.3.2 Test tube, capacity 5oml,
47、for the xylene (3.2.2.1) and the acetone (3.2.2.4). 3.2.33 Burette, capacity 5ml, for the potassium hydroxide solution (3.2.2.3). 3.2.3.4 Pipette, capacity lomi, for the hexan-1-01 (3.2.2.2). 4 STDmBSI BS EN IS0 8985-ENGL 1978 3624667 0734677 562 EN IS0 8985:1998 7% w(VAC) 5 2 2 cw(VAC)L:5 5 w(VAC)1
48、30 30 c wfVAC 3.2.3.5 Flask, capacity 1OOml. g 1 o75 092 o, 1 3.2.3.6 Reflux condenser, at least 300m long, in accordance with IS0 4799. 3.2.3.7 Heating apparatus: sand bath, oil bath or heating jacket, adjustable to approx. 200C 3.2.3.8 Analytical balance, with an accuracy of O, lmg. 3.2.3.9 Magnet
49、ic stirrer. 3.2.4 Procedure 3.2.4.1 Determination 3.2.4.1.1 Weigh a quantity of dry polymer as shown in table 2 into the flask to the nearest 0,lmg. The mass of each sample particle shall be less than approx. 0,05g. Table 2 - Guide to the mass of sample to be used I Assumed vinyl acetate content, w(VAC) I Approximate mass of test specimen I When analysing an unknown sample, first of all carry out a preliminary test under conditions which are valid for a copolymer containing 5% to 30% vinyl acetate. 3.2.4.1.2 Add 25ml of xylene (3.2.2.1) to the conten
