1、September 2008DEUTSCHE NORM English price group 11No part of this standard may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 83.080.01!$Qf4“14667
2、17www.din.deDDIN EN ISO 6721-2Plastics Determination of dynamic mechanical properties Part 2: Torsion-pendulum method (ISO 6721-2:2008)English version of DIN EN ISO 6721-2:2008-09Kunststoffe Bestimmung dynamisch-mechanischer Eigenschaften Teil 2: Torsionspendel-Verfahren (ISO 6721-2:2008)Englische F
3、assung DIN EN ISO 6721-2:2008-09SupersedesDIN EN ISO 6721-2:1996-12www.beuth.deDocument comprises 19 pagesDIN EN ISO 6721-2:2008-09 2 National foreword This standard has been prepared by Technical Committee ISO/TC 61 “Plastics” in collaboration with Technical Committee CEN/TC 249 “Plastics”, (Secret
4、ariat: NBN, Belgium). The responsible German body involved in its preparation was the Normenausschuss Kunststoffe (Plastics Standards Committee), Technical Committee NA 054-01-03 AA Physikalische, rheologische und analytische Prfungen. The DIN Standard corresponding to the International Standard ref
5、erred to in this document is as follows: ISO 6721-1 DIN EN ISO 6721-1 Amendments This standard differs from DIN EN ISO 6721-2:1996-12 as follows: a) The standard has been editorially revised. b) Clause 2 “Normative references” has been updated. c) In subclause 5.6 “ISO 6721-3” has been corrected to
6、read “ISO 6721-1”. Previous editions DIN 53520: 1969-01 DIN 53445: 1965-11, 1986-08 DIN 53445-1: 1999-09 DIN EN ISO 6721-2: 1996-12 National Annex NA (informative) Bibliography DIN EN ISO 6721-1, Plastics Determination of dynamic mechanical properties Part 1: General principles EUROPEAN STANDARD NOR
7、ME EUROPENNE EUROPISCHE NORM EN ISO 6721-2 June 2008 ICS 83.080.01 Supersedes EN ISO 6721-2:1996 English Version Plastics - Determination of dynamic mechanical properties - Part 2: Torsion-pendulum method (ISO 6721-2:2008) Plastiques - Dtermination des proprits mcaniques dynamiques - Partie 2: Mthod
8、e au pendule de torsion (ISO 6721-2:2008) Kunststoffe - Bestimmung dynamisch mechanischer Eigenschaften - Teil 2: Torsionspendel-Verfahren (ISO 6721-2:2008) This European Standard was approved by CEN on 18 May 2008. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stip
9、ulate the conditions for giving 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 CEN Management Centre or to any CEN member. This European Standard
10、 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 CEN Management Centre has the same status as the official versions. CEN members are the national standa
11、rds bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingd
12、om. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: rue de Stassart, 36 B-1050 Brussels 2008 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 6721-2:2008: E
13、2 DIN EN ISO 6721-2:2008-09EN ISO 6721-2:2008 (E)Contents Page Foreword .3 1 Scope4 2 Normative references4 3 Terms and definitions .4 4 Principle .4 5 Test apparatus .6 6 Test specimens7 7 Number of specimens.8 8 Conditioning 8 9 Procedure.8 10 Expression of results9 11 Precision 12 12 Test report1
14、2 Annex A (normative) Influence of longitudinal force, W.13 Annex B (informative) Damping correction factor, Fd.14 Annex C (informative) Dimensional correction factor, Fc.15 Bibliography17 Foreword 3 DIN EN ISO 6721-2:2008-09EN ISO 6721-2:2008 (E)This document (EN ISO 6721-2:2008) has been prepared
15、by Technical Committee ISO/TC 61 “Plastics” in collaboration with Technical Committee CEN/TC 249 “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
16、 December 2008, and conflicting national standards shall be withdrawn at the latest by December 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
17、 patent rights. This document supersedes EN ISO 6721-2:1996. According to the CEN/CENELEC Internal 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
18、, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, 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 IS
19、O 6721-2:2008 without any modification. 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 the torsional modulus, as a function of temperature, for small deformations within the f
20、requency 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 available plastics), gives information on the transition regions (for example the glass tran
21、sition 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, Plastics Determination of dynamic mechanical properties Part 3: Flexural vibration Resonanc
22、e-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 methods at low frequencies. 2 Normative references The following referenced documents are
23、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. ISO 6721-1:2001, Plastics Determination of dynamic mechanical properties Part 1: General
24、 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 clamps, one of them fixed and the other connected to a disc, which acts as an inertial me
25、mber, 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, Table 2, and the type of modulus is Gtoas defined in ISO 6721-1:2001, Table 3. The inert
26、ial 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. 4 DIN EN ISO 6721-2:2008-09EN ISO 6721-2:2008 (E)Key 1 upper (fixed) clamp 4 lower (movable) clamp 2 tem
27、perature-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 temperature-controlled chamber 4 rod 8 lower (fixed) clamp Figure 2 Apparatus for method B 5 DIN EN ISO 6721-2:20
28、08-09EN ISO 6721-2:2008 (E)During a temperature run, the same inertial member can be used throughout the whole run, which results in a frequency decreasing naturally with increasing temperature, or the inertial member can be replaced at intervals by a member of different moment of inertia in order t
29、o keep the frequency approximately constant. During the test, the frequency and the decaying amplitude are measured. From these quantities, the storage component Gtoand loss component Gtoof the torsional complex modulus G*tocan be calculated. 5 Test apparatus 5.1 Pendulum Two types of torsion pendul
30、um 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, Figure 1); b) the inertial member is suspended from a wire attached to a counterweight and the upper end of the specimen is excited
31、(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 rod) and a temperature-controlled chamber enclosing the specimen and the clamps. For method B, a counterweight and connecting wire
32、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 function of the torsional stiffness of the specimen, so that the temperature-dependent natural frequency of the system lies betw
33、een 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 be used throughout a run. NOTE For certain materials, e.g. filled polymers, a value of I of about 5 105kgm2may be necessary. If a
34、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 inertia to be varied in steps of less than 20 %, i.e. the frequency to be corrected in steps of less than 10 %. When testing standar
35、d 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 inertial member, the lower clamp and the connecting rod shall be such that the weight, W, carried by the specimen is not too high see
36、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 that the longitudinal force, W, acting on the specimen is minimized see Annex A, Equation (A.2). The wire supporting these parts
37、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 be self-aligning in order to ensure that the specimen axis remains aligned with the axis of rotation and 6 DIN EN ISO 6721-2:2008
38、-09EN ISO 6721-2:2008 (E)the test specimen remains adequately secured over the whole temperature range without distortion occurring, thus allowing the 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 (consistin
39、g of the movable clamp, the inertial member and the connecting rod) shall be determined experimentally. To prevent heat passing from the specimen out of the temperature-controlled chamber and in the opposite direction, the rod connecting the movable clamp and the inertial member shall be thermally n
40、on-conducting. 5.4 Oscillation-inducing device The oscillation-inducing device shall be capable of applying to the pendulum a torsional impulse such that 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 directi
41、on for low-modulus materials (such as elastomers). 5.5 Oscillation-frequency and oscillation-amplitude recording equipment Optical, electrical or other recording systems may be used provided they have no significant influence on the oscillating system. The entire equipment for measuring frequency an
42、d 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 Gas 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-spe
43、cimen 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
44、10 mm thickness, h: 0,13 mm to 2 mm, preferably 1 mm 7 DIN EN ISO 6721-2:2008-09EN ISO 6721-2:2008 (E)Specimens which are rectangular in cross-section but whose thickness and/or width varies along the main axis of the specimen by more than 3 % of the mean value shall not be used. When comparing diff
45、erent materials, the dimensions of the specimens shall be identical. Specimen dimensions differing from the preferred ones (50 mm 10 mm 1 mm) should be chosen to conserve geometric similarity with the preferred specimen shape. Alternative specimen shapes may be used (e.g. cylindrical or tubular); in
46、 such cases, dimensions and tolerances shall be agreed upon by the interested parties. 6.3 Preparation See ISO 6721-1:2001, Subclause 6.3. 7 Number of specimens See ISO 6721-1:2001, Clause 7. 8 Conditioning See ISO 6721-1:2001, Clause 8. If mechanical conditioning of the specimen is required, the sp
47、ecimen shall be twisted through an angle greater than 5, but less than 90 in both directions about the torsional-test axis and returned to its normal position. 9 Procedure 9.1 Test atmosphere See ISO 6721-1:2001, Subclause 9.1. 9.2 Measurement of specimen cross-section See ISO 6721-1:2001, Subclause
48、 9.2. 9.3 Mounting the test specimens Clamp the test specimen between the upper and lower clamps. The longitudinal axis of the test specimen shall coincide with the axis of rotation of the oscillating system. Any misalignment of the specimen will cause lateral oscillations that will interfere with t
49、he normal oscillation process. After clamping the test specimen, measure the distance between the clamps (the free length L) to 0,5 %. When setting up the oscillating system in the chamber, check to make sure that the test specimen is not stressed. After assembling the oscillating system complete with test specimen, and checking its alignment, start the heating or cooling (see 9.4). 9.4 Varying the temperature See ISO 6721-1:2001, Subclause 9.4. 8 DIN EN ISO 6721-2:2008-09EN ISO 6721-2:2008 (E)9.5 Performing the t
