1、BRITISH STANDARD BS EN ISO 8985:1998 Plastics Ethylene/vinyl acetate copolymer (EVAC) thermoplastics Determination of vinyl acetate content The European Standard EN ISO 8985:1998 has the status of a British Standard ICS 83.080.20BSEN ISO 8985:1998 This British Standard, having been prepared under th
2、e directionof the Sector Committee for Materials and Chemicals, waspublished underthe authorityof the Standards Committee and comesintoeffecton 15 December1998 BSI 04-1999 ISBN 0 580 29832 9 National foreword This British Standard is the English language version of EN ISO8985:1998. It is identical w
3、ith ISO8985:1998. 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 international/European committee any enquiries on the interpretation, or proposals
4、 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 Attention is drawn to the fact that CEN and CENE
5、LEC 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 may be found in the BSI Standards Catalogue
6、 under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their corre
7、ct 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, pages i and ii, theEN ISO title page, page 2, the ISO title page, page ii, pages1to15 and aback cover. This sta
8、ndard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Amendments issued since publication Amd. No. Date CommentsBSEN ISO 8985:1998 BSI 04-1999 i Contents Page National foreword Inside front cover
9、 Foreword 2 Foreword ii Text of ISO 8985 1ii blankEUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 8985 March 1998 ICS 83.080.00 Descriptors: See ISO document English version Plastics Ethylene/vinyl acetate copolymer (EVAC) thermoplastics Determination of vinyl acetate content (ISO 8985:1998
10、) Plastiques Copolymres thylne/actate de vinyle (EVAC) thermoplastiques Dosage de lactate de vinyle (ISO8985:1998) This European Standard was approved by CEN on15 February1998. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this Eu
11、ropean 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 Standard exists in three official versions (Engli
12、sh, 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 standards bodies of Austria, Belgium, CzechRepubl
13、ic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CEN European Committee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Central Secretariat: rue de Stass
14、art 36, B-1050 Brussels 1998 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO8985:1998 EEN ISO 8985:1998 BSI 04-1999 2 Foreword The text of the International Standard ISO8985:1998 has been prepared by Technical Committee ISO/TC6
15、1 “Plastics” in collaboration with Technical Committee CEN/TC249 “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 an identical text or by endorsement, at the latest by September1998, and conflicting
16、 national standards shall be withdrawn at the latest by September1998. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, CzechRepublic, Denmark, Finland, France, Germany,
17、 Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the UnitedKingdom. Endorsement notice The text of the International Standard ISO8985:1998 was approved by CEN as a European Standard without any modification. Contents Page Foreword 2 1 Scope
18、1 2 Normative references 1 3 Reference methods 1 4 Examples of test methods 9 Figure 1 Apparatus for gravimetric analysis 7 Figure 2 Example of IR spectrum and determination of absorbance 10 Figure 3 Example of a calibration curve 11 Figure 4 Drechsel wash bottle 12 Table 1 Guide to the mass of the
19、sample to be used 2 Table 2 Guide to the mass of sample to be used 3EN ISO 8985:1998 ii BSI 04-1999 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
20、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 non-governmental, in liaison with ISO, also take part in the wo
21、rk. 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 require
22、s approval by at least75% of the member bodies casting a vote. International Standard ISO8985 was prepared by Technical Committee ISO/TC61, Plastics, Subcommittee SC9, Thermoplastic materials. This second edition cancels and replaces the first edition (ISO8985:1989), which has been technically revis
23、ed. Descriptors: Plastics, thermoplastic resins, copolymers, ethylene, vinyl acetate copolymers, chemical analysis, determination of content, vinyl acetate.EN ISO 8985:1998 BSI 04-1999 1 1 Scope This International Standard specifies two categories of method for the determination of the vinyl acetate
24、 (VAC) content of ethylene/vinyl acetate (EVAC) copolymers, for use in the designation of such copolymers in accordance with ISO4613-1:1997. One category is referred to as “reference methods”, the other as “test methods”. NOTEThe abbreviation previously used for ethylene/vinyl acetate copolymer (E/V
25、AC) has been replaced by the abbreviation EVAC (see ISO1043-1:1997, Plastics Symbols and abbreviated terms Part 1: Basic polymers and their special characteristics). The “reference methods” are used to calibrate the method used for the determination of the vinyl acetate content of ethylene/vinyl ace
26、tate 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 provided they show a certain permissible repeatability. 2 Normative references The following standards contain provisions whic
27、h, 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 to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility
28、of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 4613-1:1993, Plastics Ethylene/vinyl acetate (E/VAC) moulding and extrusion materials Part1: Designation and specification. ISO 4799:1978,
29、Laboratory glassware Condensers. 3 Reference methods 3.1 Reference method 1: Hydrolysis and back titration 3.1.1 Principle 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
30、 acid is back titrated with a standard sodium hydroxide solution in the presence of phenophthalein 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. 5g
31、/l solution, or hydrochoric acid, approx. 3,7g/l solution. 3.1.2.3 Potassium hydroxide, approx. 5,6g/l ethanol solution. Dissolve5,6g of solid potassium hydroxide (KOH) in500ml of ethanol, make up to1000ml, leave to settle until the next day and decant the clear part of the solution. 3.1.2.4 Sodium
32、hydroxide, standard solution, c(NaOH) = 0,1 mol/l. NOTEThe nomenclature c(xxxx) is preferred to xxxx and used throughout, e.g. c(NaOH) = NaOH, when referring to concentrations. 3.1.2.5 Phenolphthalein, indicator solution. Dissolve0,7g of phenolphthalein in100ml of ethanol. 3.1.3 Apparatus Standard l
33、aboratory apparatus, plus the following: 3.1.3.1 Burette, 50ml capacity, for the sodium hydroxide solution (3.1.2.4). 3.1.3.2 Pipette, 30ml capacity, for the acid solution(3.1.2.2). 3.1.3.3 Pipette, 25ml capacity, for the potassium hydroxide solution (3.1.2.3). 3.1.3.4 Test tube, 50ml capacity, for
34、the xylene(3.1.2.1). 3.1.3.5 Flask, up to 300ml capacity, with stopper. 3.1.3.6 Dropping bottle, for the phenolphthalein indicator solution (3.1.2.5). 3.1.3.7 Reflux condenser, at least500 ml long, in accordance with ISO4799.EN ISO 8985:1998 2 BSI 04-1999 3.1.3.8 Heating equipment: sand bath, oil ba
35、th or heating jacket, adjustable to200 C. 3.1.3.9 Analytical balance, with an accuracy of0,1mg. 3.1.4 Procedure 3.1.4.1 Determination 3.1.4.1.1 Weigh a quantity of dry polymer as shown in Table 1 into the flask (3.1.3.5) to the nearest0,1mg. The mass of each sample particle shall be less than approx
36、. 0,05g. Table 1 Guide to the mass of the sample to be used When analysing an unknown sample, first carry out a preliminary test under conditions which are valid for a copolymer containing20% to40%VAC. 3.1.4.1.2 Add50ml of xylene (3.1.2.1) to the contents of the flask and25ml of potassium hydroxide(
37、3.1.2.3), using the pipette (3.1.3.3). Heat the flask, topped with the reflux condenser (3.1.3.7), for 2hours using the heating apparatus. After hydrolysis, remove the flask from the heating apparatus and allow to cool to ambient temperature. Add30ml of sulfuric or hydrochloric acid (3.1.2.2), using
38、 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 Carry out a blank test in parallel with the
39、 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: where 3.1.5.2 Carry out two determinations. If the results differ
40、by more than1%, discard them and run the determinations again. Report the arithmetic mean of the two 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
41、 identification of the sample; c) the result, expressed in accordance with3.1.5.2. Assumed vinyl acetate content, w(VAC) % Approximate mass of test portion g w(VAC) # 10 10 w(VAC) # 20 20 w(VAC) # 40 40 w(VAC) 1 0,5 0,3 0,2 v 1 is the volume, in millilitres, of sodium hydroxide solution used for the
42、 determination; v 2 is the volume, in millilitres, of sodium hydroxide solution used for the blank test; c 1is the actual concentration, expressed in moles per litre, of the sodium hydroxide solution used for the titration; m is the mass, in grams, of the test portion (see3.1.4.1.1).EN ISO 8985:1998
43、 BSI 04-1999 3 3.2 Reference method 2: Saponification and potentiometric titration 3.2.1 Principle A test portion is dissolved in a mixture of xylene and hexan-1-ol and the acetate groups are hydrolysed with alcoholic potassium hydroxide solution. Acetone is added to prevent copolymer precipitation.
44、 The excess alkali is titrated 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-ol. 3.2.2.3 Potassium hydroxide, appr
45、ox. 28g/l ethanolic solution. 3.2.2.4 Acetone. 3.2.2.5 Hydrochloric acid, standard solution, c(HCl) = 0,3mol/l. 3.2.2.6 Lithium chloride, 40g/l ethanolic solution. 3.2.3 Apparatus Standard laboratory equipment, plus the following: 3.2.3.1 Potentiometric titrator, with a10ml capacity burette graduate
46、d every0,02ml, a millivoltmeter 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
47、.3.2 Test tube, capacity 50ml, for the xylene(3.2.2.1) and the acetone (3.2.2.4). 3.2.3.3 Burette, capacity5ml, for the potassium hydroxide solution (3.2.2.3). 3.2.3.4 Pipette, capacity10 ml, for the hexan-1-ol (3.2.2.2). 3.2.3.5 Flask, capacity100ml. 3.2.3.6 Reflux condenser, at least300mm long, in
48、 accordance with ISO4799. 3.2.3.7 Heating apparatus: sand bath, oil bath or heating jacket, adjustable to approx. 200 C 3.2.3.8 Analytical balance, with an accuracy of0,1 mg. 3.2.3.9 Magnetic 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
49、 into the flask to the nearest0,1 mg. The mass of each sample particle shall be less than approx. 0,05g. Table 2 Guide to the mass of sample to be used When analysing an unknown sample, first of all carry out a preliminary test under conditions which are valid for a copolymer containing5% to30% vinyl acetate. Assumed vinyl acetate content, w(VAC) % Approximate mass of test specimen g w(VAC) # 2 2 w(VAC) # 5 5 w(VAC) # 30 30 w(VAC) 1 0,5 0,2 0,1EN ISO 8985:1998 4 BSI 04-1999 3.2.4.1.2 Add25ml of xylene (3.2.2.1) to
