ISO INTERNATIONAL STANDARD 6721-2 Third edition 2019-04 Plastics Determination of dynamic mechanical properties - Part 2: Torsion-pendulum method Plastiques - Détermination des propriétés mécaniques dynamiques- Partie 2: Meéthode au pendule de torsion Reference number ISO 6721-2:2019(E) ISO @ IS0 2019 IS0 6721-2:2019(E) COPYRIGHTPROTECTEDDOCUMENT @ ISO 2019 All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either IsO at the address below or Iso's member body in the country of the requester. ISO copyright office CP 401 : Ch. de Blandonnet 8 CH-1214 Vernier, Geneva Phone: +4122 749 0111 Fax: +41 22 749 09 47 Email: [email protected] Website: www.iso.org Published in Switzerland ii @ IS0 2019 - All rights reserved IS0 6721-2:2019(E) Contents Page Foreword ..iv 1 Scope .1 2 Normative references .1 3 Terms and definitions ..1 4 Principle ..1 5 Test apparatus. .3 5.1 Pendulum. .3 5.2 Inertial element .3 5.2.1 General .3 5.2.2 Method A (see Figure 1) .3 5.2.3 Method B (see Eigure 2) 3 5.3 Clamps .3 5.4 Oscillation-inducing device 4 5.5 Oscillation-frequency and oscillation-amplitude recording equipment .4 5.6 Temperature-controlled chamber 4 5.7 Gas supply. .4 5.8 Temperature-measurement device ..4 5.9 Devices for measuring test-specimen dimensions .4 6 Test specimens. ..4 6.1 General. 6.2 Shape and dimensions .4 6.3 Preparation 7 Number of specimens 8 Conditioning .5 9 Procedure .5 9.1 Test atmosphere .5 9.2 Measurementofspecimencross-section. .5 9.3 Mounting the test specimens.. .5 9.4 Varying the temperature. .5 9.5 Performing the test.. .5 10 Expression of results. .6 10.1 Symbols and correction factors ..6 10.2 Calculation of logarithmic decrement, A 1 10.3 Calculation of torsional storage modulus, Gt ..8 10.4 Calculation of torsional loss modulus, Gto ..8 11 Precision ..9 12 Test report .9 Annex A (normative) Influence of longitudinal force, W .10 Annex B (informative) Damping correction factor, Fd .11 Annex C (informative) Dimensional correction factor, Fc ..12 Bibliography. .13 @ IS0 2019 - All rights reserved iii