BS EN ISO 6721-1:2019

What is ISO 6721-1 - Mechanical properties of plastics about?

ISO 6721-1 is the first part of the ISO 6721 multi-series, and specifies the definitions and the general principles for the determination of the dynamic mechanical properties of plastics.

The various parts of ISO 6721 specify methods for the determination of the dynamic mechanical properties of rigid plastics within the region of linear viscoelastic behaviour.

This part of ISO 6721 is an introductory section that specifies the definitions and describes the general principles including all aspects that are common to the individual test methods described in the subsequent parts.

Who is ISO 6721-1 - Mechanical properties of plastics for?

ISO 6721-1 on the mechanical properties in plastic is useful for:

• Manufacturers of plastic products
• Product design engineers
• Quality control personnel

Why should you use ISO 6721-1 - Mechanical properties of plastics?

The methods specified in the first nine parts of ISO 6721 can be used for determining storage and loss moduli of plastics over a range of temperatures or frequencies by varying the temperature of the specimen or the frequency of oscillation. Plots of the storage or loss moduli, or both, are indicative of viscoelastic characteristics of the specimen. Regions of rapid changes in viscoelastic properties at particular temperatures or frequencies are normally referred to as transition regions. Furthermore, from the temperature and frequency dependencies of the loss moduli, the damping of sound and vibration of polymer or metal-polymer systems can be estimated.

Different deformation modes can produce results that are not directly comparable. For example, tensile vibration results in stress which is uniform across the whole thickness of the specimen, whereas flexural measurements are influenced preferentially by the properties of the surface regions of the specimen.

Values derived from flexural-test data will be comparable to those derived from tensile-test data only at strain levels where the stress-strain relationship is linear and for specimens which have a homogeneous structure.

Since ISO 6721-1 is the introductory document for the series, it works as the foundation document where you will find all definitions and general principles for determining the dynamic mechanical properties of plastics.

What’s changed since the last update?

BS EN ISO 6721-1:2019 supersedes BS EN ISO 6721-1:2011 which has been withdrawn. BS EN ISO 6721-1:2019 has been editorially revised and the normative references have been changed and updated.