BS 2782-3:Method 323C:1996:2007 Edition
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Methods of testing plastics – Mechanical properties – Shear vibration. Non-resonance method
| Published By | Publication Date | Number of Pages |
| BSI | 2007 | 12 |
This part of ISO 6721 describes a forced, non-resonance method for determining the components of the shear complex modulus G* of polymers at frequencies typically in the range 0,01 Hz to 100 Hz. Higher-frequency measurements can be made, but significant errors may be obtained in the dynamic properties measured (see 10.2.1 and 10.2.2). The method is suitable for measuring dynamic storage moduli in the range 0,1 MPa to 50 MPa. Although materials with moduli greater than 50 MPa may be studied, more accurate measurements of their dynamic shear properties can be made using a torsional mode of deformation (see parts 2 and 7 of ISO 6721).
This method is particularly suited to the measurement of loss factors greater than 0,1 and may therefore be conveniently used to study the variation of dynamic properties with temperature and frequency through most of the glass-rubber relaxation region (see ISO 6721-1:1994, subclause 9.4). The availability of data determined over wide ranges of both frequency and temperature enables master plots to be derived, using frequency/temperature shift procedures, which display dynamic properties over an extended frequency range at different temperatures.
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 1 | BRITISH STANDARD BS 2782-3: Method 323C: 1996 ISO 6721-6: 1996 Methods of testing Plastics – Part 3: Mechanical properties – Method 323C: Shear vibration – Non-resonance method ICS 83.080 |
| 2 | Committees responsible for this British Standard The preparation of this British Standard was entrusted to Technical Committee PRI/21, Testing of plastics, upon which the following bodies were represented: British Apparel and Textile Confederation British Plastics Federation Department of the Environment (Building Research Establishment) Department of Trade and Industry (National Physical Laboratory) Electrical and Electronic Insulation Association (BEAMA Ltd.) GAMBICA (BEAMA Ltd.) Institute of Materials Ministry of Defence Packaging and Industrial Films Association PIRA International RAPRA Technology Ltd. Royal Society of Chemistry |
| 3 | National foreword This British Standard was published by BSI. It is the UK implementation of ISO 6721-6:1996, incorporating amendment 1:2007. ISO 6721-6 is one of a ten part series of ISO 6721 methods of determination of the dynamic mechanical properties of rigid plasti… The start and finish of text introduced or altered by amendment is indicated in the text by tags !”. Tags indicating changes to ISO text carry the number of the ISO amendment. For example, text altered by ISO amendment 1 is indicated in the text by !”. The UK participation in its preparation was entrusted to Technical Committee PRI/21, Testing of plastics. A list of organizations represented on PRI/21 can be obtained on request to its secretary. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard cannot confer immunity from legal obligations. |
| 5 | 1 Scope This part of ISO 6721 describes a forced, non-resonance method for determining the components of the shear complex modulus G* of… This method is particularly suited to the measurement of loss factors greater than 0,1 and may therefore be conveniently used to… 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this part of ISO 6721… ISO 6721-1:1994, Plastics – Determination of dynamic mechanical properties – Part 1: General principles. ISO 6721-2:1994, Plastics – Determination of dynamic mechanical properties – Part 2: Torsion-pendulum method. ISO 6721-7:1996, Plastics – Determination of dynamic mechanical properties – Part 7: Torsional vibration – Non-resonance method. 3 Definitions See ISO 6721-1:1994, clause 3. 4 Principle A test-specimen assembly is subjected to a sinusoidal shear force or deformation at a frequency significantly below the fundamen… 5 Apparatus 5.1 Loading assembly The requirements for the loading assembly are that it shall permit measurements of the amplitudes of, and phase angle between, t… |
| 6 | A clamping arrangement may be used in which a single specimen of the polymer is subjected to a simple shear deformation, but pre… 5.1.1 Load stage The shear load stage shall be capable of gripping the test-specimen assembly with sufficient force to prevent any relative movem… 5.1.2 Transducers The term transducer in this part of ISO 6721 refers to any device capable of measuring the applied force or displacement, or the… 5.2 Electronic data-processing equipment Data-processing equipment shall be capable of recording the force and displacement cycle amplitudes to an accuracy of ± 1 %, the phase angle between the force and displacement cycles to an accuracy of ± 0,1˚ and the frequency to an accuracy of ± 10 %. 5.3 Temperature measurement and control See ISO 6721-1:1994, subclauses 5.3 and 5.5. 5.4 Devices for measuring test specimen dimensions See ISO 6721-1:1994, subclause 5.6. 6 Test assembly See ISO 6721-1:1994, clause 6. 6.1 Shape and dimensions A suitable design for the shear test-specimen assembly is shown in Figure 2. Here the metal end-pieces P are cylindrical, but an… The cross-sectional shape of the polymer specimens in the plane of their bonded faces is not critical, although a rectangular se… 6.2 Preparation of polymer specimens See ISO 6721-1:1994, subclause 6.2. 7 Number of test assemblies See ISO 6721-1:1994, clause 7, reading “test-specimen assemblies” for “test specimens”. 8 Conditioning See ISO 6721-1:1994, clause 8. 9 Procedure 9.1 Test atmosphere See ISO 6721-1:1994, subclause 9.1. |
| 7 | 9.2 Measuring the cross-section of the polymer specimen See ISO 6721-1:1994, subclause 9.2. 9.3 Clamping the test assembly Mount the test-specimen assembly in the load stage using a clamping force that is sufficient to prevent relative movement between each clamp and the associated end-piece under all test conditions. 9.4 Varying the temperature See ISO 6721-1:1994, subclause 9.4. 9.5 Performing the test Apply to the shear test-specimen assembly a dynamic force which yields force and displacement signal amplitudes which can be measured by the transducers to the accuracy specified in 5.1.2. Record the amplitudes of, the phase difference between and the frequencies of the force and displacement signals, as well as the… For those test conditions under which the polymer exhibits medium or high loss (for example in the glass-rubber transition regio… 10 Expression of results 10.1 Symbols |
| 8 | 10.2 Calculation of the shear storage modulus G9 An approximate value for the shear storage modulus G9a, is determined from the equation: The term in square brackets accounts for a contribution from bending to the deformation of the specimen. Values for G9/E9 typically range from 0,37 for isotropic glassy or semicrystalline polymers to 0,33 for rubbers. 10.2.1 Avoidance of test assembly resonance Equation (1) becomes invalid as the drive frequency approaches the fundamental shear resonance frequency fs of the test-specimen assembly given approximately by where r is the polymer density in kilograms per cubic metre. An error in the use of equation (1) becomes significant at applied frequencies such that Calculations of dynamic properties shall therefore be confined to frequencies below 0,08fs. 10.2.2 Correction for transducer resonance At sufficiently high frequencies, the applied deformation will excite the force transducer into resonance. The resonance frequency fF is given by The transducer output will have a significant error for all applied frequencies The resonance frequency fF of the force transducer and supported mass mF can be determined directly by recording the natural frequency of the transducer output after striking the attached clamp without the test-specimen assembly. The test-specimen assembly stiffness corrected for transducer resonance is given to a good approximation by the equation It is recommended that equations (4) and (5) be used to select a force transducer whose resonance frequency is above the frequency range for which a correction to the force measurement is necessary. 10.2.3 Correction for apparatus compliance If ka is greater than 0,02k., then the compliance of the test-specimen assembly is not negligible and the measured displacement differs significantly from that of the assembly. The following correction shall then be applied: where dG is given by equation (8). The value of k cos dG obtained from equation (7) shall be used in place of ka cos dGa in equation (1) to give a more accurate estimate for G9a. 10.3 Calculation of the shear loss factor tan dG An approximate value for the shear loss factor is tan dGa. If ka is greater than 0,02k. then the compliance of the loading assembly will influence the accuracy of the phase angle measurement. The loss factor shall then be obtained using the equation 10.4 Calculation of the shear loss modulus Calculate the loss modulus G0 from the equation 10.5 Presentation of data as a function of temperature See ISO 6721-1:1994, subclause 9.4. |
| 9 | 11 Precision The precision of this test method is not known because interlaboratory data are not available. When interlaboratory data are obtained, a precision statement will be added at the following revision. 12 Test report The test report shall contain the following information: a) a reference to this part of ISO 6721; b) to m) see ISO 6721-1:1994, clause 12; n) the dynamic shear strain amplitude, given approximately by sA/L. |
| 12 | BS 2782-3: Method 323C: 1996 ISO 6721-6: 1996 BSI 389 Chiswick High Road London W4 4AL BSI – British Standards Institution BSI is the independent national body responsible for preparing British Standards. It presents the UK view on standards in Europe and at the international level. It is incorporated by Royal Charter. Revisions British Standards are updated by amendment or revision. Users of British Standards should make sure that they possess the latest amendments or editions. It is the constant aim of BSI to improve the quality of our products and services. We would be grateful if anyone finding an ina… BSI offers members an individual updating service called PLUS which ensures that subscribers automatically receive the latest editions of standards. Buying standards Orders for all BSI, international and foreign standards publications should be addressed to Customer Services. Tel: +44 (0)20 89… In response to orders for international standards, it is BSI policy to supply the BSI implementation of those that have been published as British Standards, unless otherwise requested. Information on standards BSI provides a wide range of information on national, European and international standards through its Library and its Technical… Subscribing members of BSI are kept up to date with standards developments and receive substantial discounts on the purchase pri… Information regarding online access to British Standards via British Standards Online can be found at http://www.bsi-global.com/bsonline. Further information about BSI is available on the BSI website at http:// www.bsi-global.com. Copyright Copyright subsists in all BSI publications. BSI also holds the copyright, in the UK, of the publications of the international st… This does not preclude the free use, in the course of implementing the standard, of necessary details such as symbols, and size,… Details and advice can be obtained from the Copyright & Licensing Manager. Tel: +44 (0)20 8996 7070. Fax: +44 (0)20 8996 7553. Email: [email protected]. |
