BS ISO 6721-7:2019
$102.76
Plastics. Determination of dynamic mechanical properties – Torsional vibration. Non-resonance method
| Published By | Publication Date | Number of Pages |
| BSI | 2019 | 18 |
This document describes a torsional, non-resonance method for determining the components of the shear complex modulus G* of solid polymers in the form of bars or rods at frequencies typically in the range 0,001 Hz to 100 Hz. Higher-frequency measurements can be made, but significant errors in the dynamic properties measured are likely to result (see 10.2.1 and 10.2.2). The method is suitable for measuring dynamic storage moduli ranging from about 10 MPa, which is typical of values obtained for stiff rubbers, to values of about 10 GPa which are representative of fibre-reinforced plastics. Although materials with moduli less than 10 MPa can be studied, more accurate measurements of their dynamic properties can be made using simple shear (see ISO 6721-6) or torsional deformations of thin layers between parallel plates.
This method is particularly suited to the measurement of loss factors greater than 0,02 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). The availability of data determined over wide ranges of both frequency and temperature enable master plots to be derived, using frequency-temperature shift procedures, which display dynamic properties over an extended frequency range at different temperatures.
Although loss factors below 0,1 can be more accurately determined using the torsion pendulum (see ISO 6721-2), the method described in this document enables a much wider and continuous frequency range to be covered.
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 2 | National foreword |
| 6 | Foreword |
| 7 | 1 Scope 2 Normative references 3 Terms and definitions 4 Principle |
| 8 | 5 Test device 5.1 Loading assembly 5.1.1 General 5.1.2 Clamps 5.1.3 Transducers |
| 9 | 5.2 Electronic data-processing equipment 5.3 Temperature measurement and control 5.4 Devices for measuring test specimen dimensions 6 Test specimens 6.1 General 6.2 Shape and dimensions 6.3 Preparation 7 Number of specimens 8 Conditioning 9 Procedure 9.1 Test atmosphere |
| 10 | 9.2 Measuring the cross-section of the specimen 9.3 Clamping the specimen 9.4 Varying the temperature 9.5 Performing the test 10 Expression of results 10.1 Symbols |
| 11 | 10.2 Calculation of the shear storage modulus G′ 10.2.1 General |
| 12 | 10.2.2 Avoidance of specimen resonance 10.2.3 Correction for transducer resonance |
| 13 | 10.2.4 Correction for apparatus compliance 10.2.5 Application of a length correction 10.3 Calculation of the shear loss factor tan δG |
| 14 | 10.4 Calculation of the shear loss modulus 10.5 Presentation of data as a function of temperature 11 Precision 12 Test report |
| 16 | Bibliography |
