1、BS EN ISO6721-2:2008ICS 83.080.01NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDPlastics Determination ofdynamic mechanicalpropertiesPart 2: Torsion-pendulum method (ISO6721-2:2008)This British Standardwas published under theauthority of the StandardsPolicy and
2、 StrategyCommittee on 31 July 2008 BSI 2008ISBN 978 0 580 62798 9Amendments/corrigenda issued since publicationDate CommentsBS EN ISO 6721-2:2008National forewordThis British Standard is the UK implementation of EN ISO 6721-2:2008.It supersedes BS EN ISO 6721-2:1996 which is withdrawn.The UK partici
3、pation in its preparation was entrusted to TechnicalCommittee PRI/21, Testing of plastics.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisionsof a contract. Users are responsible for
4、 its correct application.Compliance with a British Standard cannot confer immunityfrom legal obligations.EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN ISO 6721-2June 2008ICS 83.080.01 Supersedes EN ISO 6721-2:1996 English VersionPlastics - Determination of dynamic mechanical properties - Part2:
5、Torsion-pendulum method (ISO 6721-2:2008)Plastiques - Dtermination des proprits mcaniquesdynamiques - Partie 2: Mthode au pendule de torsion (ISO6721-2:2008)Kunststoffe - Bestimmung dynamisch mechanischerEigenschaften - Teil 2: Torsionspendel-Verfahren (ISO6721-2:2008)This European Standard was appr
6、oved by CEN on 18 May 2008.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstand
7、ards may be obtained on application to the CEN Management Centre or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to
8、the CEN Management Centre has the same status as theofficial versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Nether
9、lands, Norway, Poland, Portugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2008 CEN All rights of exploitation in a
10、ny form and by any means reservedworldwide for CEN national Members.Ref. No. EN ISO 6721-2:2008: EBS EN ISO 6721-2:2008EN ISO 6721-2:2008 (E) 3 Foreword This document (EN ISO 6721-2:2008) has been prepared by Technical Committee ISO/TC 61 “Plastics” in collaboration with Technical Committee CEN/TC 2
11、49 “Plastics” the secretariat of which is held by NBN. 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 December 2008, and conflicting national standards shall be withdrawn at the latest by Decembe
12、r 2008. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. This document supersedes EN ISO 6721-2:1996. According to the CEN/CENELEC Inte
13、rnal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Ma
14、lta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. Endorsement notice The text of ISO 6721-2:2008 has been approved by CEN as a EN ISO 6721-2:2008 without any modification. BS EN ISO 6721-2:2008ISO 6721-2:2008(E) ISO 2008 All r
15、ights reserved iiiContents Page Foreword iv 1 Scope . 1 2 Normative references . 1 3 Terms and definitions. 1 4 Principle. 1 5 Test apparatus 3 6 Test specimens . 4 7 Number of specimens 5 8 Conditioning 5 9 Procedure 5 10 Expression of results . 6 11 Precision 9 12 Test report . 9 Annex A (normativ
16、e) Influence of longitudinal force, W 10 Annex B (informative) Damping correction factor, Fd11 Annex C (informative) Dimensional correction factor, Fc12 Bibliography . 14 BS EN ISO 6721-2:2008ISO 6721-2:2008(E) iv ISO 2008 All rights reservedForeword ISO (the International Organization for Standardi
17、zation) is a worldwide federation of national standards bodies (ISO member bodies). 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 b
18、e represented on that committee. International organizations, governmental and 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 Standa
19、rds are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an Inter
20、national Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 6721-2
21、was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 2, Mechanical properties. This second edition cancels and replaces the first edition (ISO 6721-2:1994), of which it constitutes a minor revision. It also incorporates the Technical Corrigendum ISO 6721-2:1994/Cor.1:1995. Apart
22、from the inclusion of the Corrigendum (which concerns the last sentence in the first paragraph in Annex C), the main changes are the updating of the references and the correction of ISO 6721-3 to ISO 6721-1 in Subclause 5.6. ISO 6721 consists of the following parts, under the general title Plastics
23、Determination of dynamic mechanical properties: Part 1: General principles Part 2: Torsion-pendulum method Part 3: Flexural vibration Resonance-curve method Part 4: Tensile vibration Non-resonance method Part 5: Flexural vibration Non-resonance method Part 6: Shear vibration Non-resonance method Par
24、t 7: Torsional vibration Non-resonance method Part 8: Longitudinal and shear vibration Wave-propagation method Part 9: Tensile vibration Sonic-pulse propagation method Part 10: Complex shear viscosity using a parallel-plate oscillatory rheometer BS EN ISO 6721-2:2008INTERNATIONAL STANDARD ISO 6721-2
25、:2008(E) ISO 2008 All rights reserved 1Plastics Determination of dynamic mechanical properties Part 2: Torsion-pendulum method 1 Scope This part of ISO 6721 specifies two methods (A and B) for determining the linear dynamic mechanical properties of plastics, i.e. the storage and loss components of t
26、he torsional modulus, as a function of temperature, for small deformations within the frequency range from 0,1 Hz to 10 Hz. The temperature dependence of these properties, measured over a sufficiently broad range of temperatures (for example from 50 C to +150 C for the majority of commercially avail
27、able plastics), gives information on the transition regions (for example the glass transition and the melting transition) of the polymer. It also provides information concerning the onset of plastic flow. The two methods described are not applicable to non-symmetrical laminates (see ISO 6721-3, Plas
28、tics Determination of dynamic mechanical properties Part 3: Flexural vibration Resonance-curve method). The methods are not suitable for testing rubbers, for which the user is referred to ISO 4664-2, Rubber, vulcanized or thermoplastic Determination of dynamic properties Part 2: Torsion pendulum met
29、hods at low frequencies. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. I
30、SO 6721-1:2001, Plastics Determination of dynamic mechanical properties Part 1: General principles 3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 6721-1:2001, Clause 3, apply. 4 Principle A test specimen of uniform cross-section is gripped by two cl
31、amps, one of them fixed and the other connected to a disc, which acts as an inertial member, by a rod. The end of the specimen connected to the disc is excited, together with the disc, to execute freely decaying torsional oscillations. The oscillation mode is that designated IV in ISO 6721-1:2001, T
32、able 2, and the type of modulus is Gtoas defined in ISO 6721-1:2001, Table 3. The inertial member is suspended either from the specimen (method A, see Figure 1) or from a wire (method B, see Figure 2). In the latter case, the wire is also part of the elastically oscillating system. BS EN ISO 6721-2:
33、2008ISO 6721-2:2008(E) 2 ISO 2008 All rights reservedKey 1 upper (fixed) clamp 4 lower (movable) clamp 2 temperature-controlled chamber 5 rod 3 test specimen 6 inertial member Figure 1 Apparatus for method A Key 1 counterweight 5 upper (movable) clamp 2 wire 6 test specimen 3 inertial member 7 tempe
34、rature-controlled chamber 4 rod 8 lower (fixed) clamp Figure 2 Apparatus for method B BS EN ISO 6721-2:2008ISO 6721-2:2008(E) ISO 2008 All rights reserved 3During a temperature run, the same inertial member can be used throughout the whole run, which results in a frequency decreasing naturally with
35、increasing temperature, or the inertial member can be replaced at intervals by a member of different moment of inertia in order to keep the frequency approximately constant. During the test, the frequency and the decaying amplitude are measured. From these quantities, the storage component Gtoand lo
36、ss component Gtoof the torsional complex modulus G*tocan be calculated. 5 Test apparatus 5.1 Pendulum Two types of torsion pendulum are specified for use with this part of ISO 6721: a) the inertial member is suspended from the test specimen and the lower end of the specimen is excited (method A, Fig
37、ure 1); b) the inertial member is suspended from a wire attached to a counterweight and the upper end of the specimen is excited (method B, Figure 2). Both types of pendulum consists of an inertial member, two clamps for gripping the specimen (one of which is connected to the inertial member by a ro
38、d) and a temperature-controlled chamber enclosing the specimen and the clamps. For method B, a counterweight and connecting wire are also required. 5.2 Inertial member 5.2.1 General The moment of inertia, I, of the inertial member, which may be made of aluminium, for instance, shall be selected as a
39、 function of the torsional stiffness of the specimen, so that the temperature-dependent natural frequency of the system lies between approximately 0,1 Hz and 10 Hz. When testing standard specimens (see 6.2), a moment of inertia, I, of about 3 105kgm2is recommended if the same inertial member is to b
40、e used throughout a run. NOTE For certain materials, e.g. filled polymers, a value of I of about 5 105kgm2may be necessary. If a constant frequency is desired over a broad temperature range, interchangeable inertial members with different values of I may be used, thereby permitting the moment of ine
41、rtia to be varied in steps of less than 20 %, i.e. the frequency to be corrected in steps of less than 10 %. When testing standard specimens (see 6.2) at a frequency of about 1 Hz, a maximum moment of inertia of about 3 103kgm2is recommended. 5.2.2 Method A (see Figure 1) The total mass of the inert
42、ial member, the lower clamp and the connecting rod shall be such that the weight, W, carried by the specimen is not too high see Annex A, Equation (A.2). 5.2.3 Method B (see Figure 2) The total mass of the inertial member, the upper clamp and the rod must be balanced by a suitable counterweight, so
43、that the longitudinal force, W, acting on the specimen is minimized see Annex A, Equation (A.2). The wire supporting these parts is part of the elastically oscillating system. 5.3 Clamps The clamps shall be designed to prevent movement of the portion of the specimens gripped within them. They shall
44、be self-aligning in order to ensure that the specimen axis remains aligned with the axis of rotation and BS EN ISO 6721-2:2008ISO 6721-2:2008(E) 4 ISO 2008 All rights reservedthe test specimen remains adequately secured over the whole temperature range without distortion occurring, thus allowing the
45、 free length of the specimen to be accurately determined. The movable clamp shall be of low mass. The moment of inertia of the whole system (consisting of the movable clamp, the inertial member and the connecting rod) shall be determined experimentally. To prevent heat passing from the specimen out
46、of the temperature-controlled chamber and in the opposite direction, the rod connecting the movable clamp and the inertial member shall be thermally non-conducting. 5.4 Oscillation-inducing device The oscillation-inducing device shall be capable of applying to the pendulum a torsional impulse such t
47、hat the pendulum oscillates initially through an angle of not more than 1,5 in each direction for normal materials, or not more than 3 in each direction for low-modulus materials (such as elastomers). 5.5 Oscillation-frequency and oscillation-amplitude recording equipment Optical, electrical or othe
48、r recording systems may be used provided they have no significant influence on the oscillating system. The entire equipment for measuring frequency and amplitude shall be accurate to 1 % (within the transition region 5 %). 5.6 Temperature-controlled chamber See ISO 6721-1:2001, Subclause 5.3. 5.7 Ga
49、s supply See ISO 6721-1:2001, Subclause 5.4. 5.8 Temperature-measurement device See ISO 6721-1:2001, Subclause 5.5. 5.9 Devices for measuring test-specimen dimensions See ISO 6721-1:2001, Subclause 5.6. 6 Test specimens 6.1 General See ISO 6721-1:2001, Clause 6. 6.2 Shape and dimensions Rectangular test specimens having the following dimensions are recommended: free length, L: 40 mm to 120 mm, preferably 50 mm width, b: 5 mm to 11 mm, preferably 10 mm thickness, h: 0,
