ISO INTERNATIONAL STANDARD 6721-7 Second edition 2019-04 Plastics Determination of dynamic mechanical properties - Part 7: Torsional vibration Non- resonance method Plastiques - Détermination des propriétés mécaniques dynamiques- Partie 7: Vibration en torsion - Meéthode hors résonance Reference number ISO 6721-7:2019(E) osi @ IS0 2019 IS0 6721-7:2019(E) COPYRIGHTPROTECTEDDOCUMENT @ IS0 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: +41 22 749 01 11 Fax: +41 22 749 09 47 Email: [email protected] Website: www.iso.org Published in Switzerland ii @ IS0 2019 - All rights reserved IS0 6721-7:2019(E) Contents Page Foreword ..iv 1 Scope .1 2 Normative references 3 Terms and definitions 4 Principle ..1 5 Test device 2 5.1 Loading assembly .2 5.1.1 General. .2 5.1.2 Clamps, .2 5.1.3 Transducers .2 5.2 Electronic data-processing equipment 3 5.3 Temperature measurement and control .3 5.4 Devices for measuring test specimen dimensions .3 6 Test specimens. .3 6.1 General. ..3 6.2 Shape and dimensions .3 6.3 Preparation .3 7 Number of specimens ..3 8 Conditioning ..3 9 Procedure ..3 9.1 Test atmosphere .3 9.2 Measuring the cross-section of the specimen ..4 9.3 Clamping the specimen. .4 9.4 Varying the temperature .4 9.5 Performing the test.. .4 10 Expression of results .5 10.1 Symbols .5 10.2 Calculation of the shear storage modulus G' .6 10.2.1 General .6 10.2.2 Avoidance of specimen resonance .6 10.2.3 Correction for transducer resonance. .7 10.2.4 Correction for apparatus compliance 10.2.5 Application of a length correction 7 10.3 Calculation of the shear loss factor tan dg ..8 10.4 Calculation of the shear loss modulus. 10.5 Presentation of data as a function of temperature ..8 11 Precision ...8 12 Test report ..8 Bibliography .10 IS0 2019 - All rights reserved ii