ISO-6721-10-1999.pdf
? Reference number ISO 6721-10:1999(E) INTERNATIONAL STANDARD ISO 6721-10 Second edition 1999-12-15 Plastics Determination of dynamic mechanical properties Part 10: Complex shear viscosity using a parallel- plate oscillatory rheometer Plastiques Détermination des propriétés mécaniques dynamiques Partie 10: Viscosité complexe en cisaillement à l'aide d'un rhéomètre à oscillations à plateaux parallèles Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/19/2007 22:25:57 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 6721-10:1999(E) ©ISO 1999 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the publisher. International Organization for Standardization Case postale 56 ? CH-1211 Genève 20 ? Switzerland Internetisoiso.ch Printed in Switzerland ii Contents 1Scope1 2Normative references1 3Terms and definitions.1 4Principle .2 5Apparatus.2 6Sampling 4 7Procedure.4 8Expression of results7 9Precision 9 10Test report10 Annex A (informative) Uncertainty limits 12 Bibliography15 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/19/2007 22:25:57 MDTNo reproduction or networking permitted without license from IHS -,-,- ©ISOISO 6721-10:1999(E) iii 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 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 work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. International Standard ISO 6721-10 was prepared by Technical Committee ISO/TC 61,Plastics, Subcommittee SC 2,Mechanical properties. This second edition cancels and replaces the first edition (ISO 6721-10:1997), which has been technically revised. ISO 6721 consists of the following parts, under the general titlePlastics 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 ?Part 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 Annex A of this part of ISO 6721 is for information only. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/19/2007 22:25:57 MDTNo reproduction or networking permitted without license from IHS -,-,- Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/19/2007 22:25:57 MDTNo reproduction or networking permitted without license from IHS -,-,- INTERNATIONAL STANDARD©ISOISO 6721-10:1999(E) 1 Plastics Determination of dynamic mechanical properties Part 10: Complex shear viscosity using a parallel-plate oscillatory rheometer 1 Scope This part of ISO 6721 specifies the general principles of a method for determining the dynamic rheological properties of polymer melts at angular frequencies typically in the range 0,01 rad.s?1to 100 rad.s?1by means of an oscillatory rheometer with a parallel-plate geometry. Angular frequencies outside this range can also be used (see note 1). The method is used to determine values of the following dynamic rheological properties: complex shear viscosity ?*, dynamic shear viscosity ?', the out-of-phase component of the complex shear viscosity ?'', complex shear modulus G*, shear loss modulus G'' and shear storage modulus G'. It is suitable for measuring complex shear viscosity values typically up to approximately 10 MPa.s (see note 2). NOTE 1The angular-frequency measurement range is limited by the specification of the measuring instrument and also by the response of the specimen. When testing using angular frequencies lower than 0,1 rad.s1the test time can increase significantly as the time taken to obtain a single measurement is proportional to the reciprocal of the angular frequency. Consequently, when testing at low angular frequencies degradation or polymerization of the specimen is more likely to occur and have an effect on the results. At high angular frequencies the specimen may distort or fracture at the edge, consequently invalidating the test results. NOTE 2The range of complex shear viscosity values that can be measured is dependent on the specimen dimensions and also the specification of the measuring instrument. For a specimen of given dimensions, the upper limit of the range is limited by the machine's torque capacity, angular-displacement resolution and compliance. However, correction can be made for compliance effects. 2 Normative references The following normative documents contain provisions which, through reference in this text, constitute provisions of this part of ISO 6721. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this part of ISO 6721 are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registers of currently valid International Standards. ISO 472:1999,Plastics Vocabulary. ISO 5725-1:1994,Accuracy (trueness and precision) of measurement methods and results Part 1: General principles and definitions. ISO 6721-1:1994,Plastics Determination of dynamic mechanical properties Part 1: General principles. 3 Terms and definitions For the purposes of this part of ISO 6721, the terms and definitions given in ISO 6721-1:1994, ISO 5725-1:1994 and ISO 472:1999 apply, plus the following: Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/19/2007 22:25:57 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 6721-10:1999(E) ©ISO 2 3.1 controlled-strain mode testing by applying a sinusoidal angular displacement of constant amplitude 3.2 controlled-stress mode testing by applying a sinusoidal torque of constant amplitude 3.3 complex shear viscosity ?* the ratio of dynamic stress, given by ?(t) = ?0expi?t, and dynamic rate of strain? ?( ),twhere the shear strain ? (t) is given by ? (t) = ?0expi(?t ? ?), of a viscoelastic material that is subjected to a sinusoidal vibration, where ?0and ?0 are the amplitudes of the stress and strain cycles, ? is the angular frequency, ? is the phase angle between the stress and strain and t is time It is expressed in pascal seconds. 3.4 dynamic shear viscosity ?' the real part of the complex shear viscosity The dynamic shear viscosity is expressed in pascal seconds. 3.5 out-of-phase component of the complex shear viscosity ?'' the imaginary part of the complex shear viscosity The out-of-phase component of the complex shear viscosity is expressed in pascal seconds. 4 Principle The specimen is held between two concentric, circular parallel plates (see Figure 1). The thickness of the specimen is small compared with the diameter of the plates. The specimen is subjected to either a sinusoidal torque or a sinusoidal angular displacement of constant angular frequency. These are referred to as “controlled-stress“ or “controlled-strain“ test modes, respectively. When using the controlled-stress mode, the resultant displacement and the phase shift between the torque and displacement are measured. When using the controlled-strain mode, the resultant torque and the phase shift between the displacement and torque are measured. The complex shear modulus G*, shear storage modulus G', shear loss modulus G'', phase angle ? and corresponding shear viscosity terms (see clause 3) are determined from the measured torque and displacement and the specimen dimensions. In deriving these values, it is assumed that the specimen exhibits a linear-viscoelastic response. The mode of oscillation used is designated as oscillatory mode I (see ISO 6721-1:1994, clause 4). 5 Apparatus 5.1 Measurement apparatus The measurement apparatus shall consist of two concentric, rigid, circular parallel plates between which the specimen is placed (see Figure 1). One of these plates shall be made to oscillate at a constant angular frequency while the other remains at rest. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/19/2007 22:25:57 MDTNo reproduction or networking permitted without license from IHS -,-,- ©ISOISO 6721-10:1999(E) 3 The requirements on the apparatus are that it shall permit measurement of the amplitudes of the torque and the angular displacement and the phase difference between them for a specimen subjected to either a sinusoidal torque or a sinusoidal displacement of constant angular frequency. A torque-measuring device shall be connected to one of the plates, thus permitting measurement of the torque required to overcome the viscoelastic resistance of the specimen. An angular-displacement-measuring device shall be fitted to the moving plate, thus permitting determination of its angular displacement and angular frequency. The apparatus shall be capable of measuring the torque to within ?2 % of the minimum torque amplitude used to determine the dynamic properties. The apparatus shall be capable of measuring the angular displacement to within ?20 ? 10?6rad. The apparatus shall be capable of measuring the angular frequency to within ?2 % of the absolute value. Key 1Test specimen ? = angular frequency d = specimen thickness D = diameter of plate Figure 1 Parallel-plate rheometer geometry 5.2 Temperature-controlled enclosure Heating may be provided by the use of forced convection, radio-frequency heating or other suitable means. An environmental chamber surrounding the plate/specimen assembly can be used to provide specific test environments, for example a nitrogen atmosphere. Check that the chamber is not in contact with the plate/specimen assembly. 5.3 Temperature measurement and control The test temperature should preferably be measured using a device that is either in contact with or embedded in the fixed plate. The test temperature shall be accurate to within ?0,5 ?C of the set temperature for set temperatures up to 200 ?C, within ?1,0 °C for temperatures in the range 200 °C to 300 ?C, and within ?1,5 °C for temperatures above 300 °C. The temperature-measuring device shall have a resolution of 0,1 ?C and shall be calibrated using a device accurate to within ?0,1 ?C. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/19/2007 22:25:57 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 6721-10:1999(E) ©ISO 4 5.4 Plate/specimen assembly The plate/specimen assembly comprises two concentric, circular parallel plates with the specimen held between them. The plates shall have a surface finish corresponding to a maximum roughness of Ra = 0,25 µm and shall have no visible imperfections. The results may be dependent on the type of material that is used to form the surfaces of the plates. This can be identified by testing using plates with different surface materials. The plate diameter D is typically in the range 20 mm to 50 mm. It shall be measured to within ?0,01 mm. The specimen thickness d is defined by the plate separation and shall be determined to within ?0,01 mm. It is recommended that the specimen thickness lie in the range 0,5 mm to 3 mm and that the ratio of the plate diameter to the specimen thickness lie in the range 10 to 50 in order to minimize errors in the determination of properties. For low-viscosity polymeric liquids, it may be necessary to employ dimensions outside these recommended ranges. The total variation in the plate separation due to non-parallelism of the plates shall be less than ?0,01 mm. Variation in the plate separation during testing shall be less than ?0,01 mm. 5.5 Calibration The rheometer shall be calibrated periodically by measuring the torque, angular-displacement and angular- frequency response of the machine, or by using reference liquids of known complex viscosity, in accordance with the instrument manufacturer's instructions. It is preferable that the complex viscosities of reference liquids used for calibration lie in the same range as those of the specimens to be measured. It is preferable that calibration be carried out at the test temperature. 6Sampling The sampling procedure, including any special methods of specimen preparation and introduction into the rheometer, shall be as specified in the relevant materials standard or as otherwise agreed. As the test specimens are typically small, being of the order of 3 g to 5 g, it is essential that they are representative of the material being sampled. If samples or specimens are hygroscopic or contain volatile ingredients, then they shall be stored to prevent or minimize any changes in viscosity. Drying of samples may be required prior to preparing test specimens. The test specimens shall be in the form of a disc when produced by injection or compression moulding or by cutting from sheet. Alternativel
