What is ISO 6721‑3 about?
ISO 6721‑3 is part three of a series of international standards that specifies a bending-vibration method based upon resonance curves for determining the flexural complex modulus Ef* of homogeneous plastics and the damping properties of laminated plastics intended for acoustic insulation.
For example, systems consisting of a metal sheet coated with a damping plastic layer, or sandwich systems consisting of two sheet-metal layers with an intermediate plastic layer. For many purposes, it is useful to determine these properties as a function of temperature and frequency.
Who is ISO 6721‑3 for?
ISO 6721‑3 on properties of plastics is useful for:
- Plastic manufacturers
- Polymer manufacturers
- Mechanical engineers
Why should you use ISO 6721‑3?
In the flexural vibration method, a cantilever-type specimen is prepared from thin-film layer, and the specimen is vibrated by application of external force.
Dynamic mechanical analysis (abbreviated DMA) is a technique used to study and characterize materials. It is most useful for studying the viscoelastic behaviour of polymers. A sinusoidal stress is applied and the strain in the material is measured, allowing one to determine the complex modulus.
Dynamic mechanical properties can be used to identify glass transition temperature and polymer composition. These can help you identify the strength, durability and sustainability of the plastic. This determination can be done by using ISO 6721‑3 which specifies a bending-vibration method based upon resonance curves for determining the flexural complex modulus of homogeneous plastics.
Adopting the test methods and practices in compliance with ISO 6721-3 will help you gain perspective regarding the properties of materials and components, to improve functionality of your end-product application.
What’s changed since the last update?
BS EN ISO 6721‑3:2021 supersedes BS EN ISO 67213:1996, which is withdrawn. BS EN ISO 6721‑3:2021 includes some technical changes with respect to BS EN ISO 67213:1996. These are:
- The document has been revised editorially
- The normative references have been updated
- The NOTE in Clause 3 has been moved to Clause 4
- The method of specimen density measurement has been defined