The strength and stiffness of plastics are important for the design of products and parts in order to predict their performance under stress. This is especially important in structural, load bearing applications. Plastic materials can be stiff, rigid and strong or opposite and the final product can furthermore be isotropic or anisotropic. There are a wide range of methods to test and describe such mechanical properties.
ISO 527-1/2 - Determination of tensile properties
ASTM D638 - Tensile Properties of Plastics
ASTM D412 Test Methods for Vulcanized Rubber and Thermoplastic Elastomers
ISO37 - Tensile Testing of Rubber, vulcanized or thermoplastic
ISO 178 - Determination of flexural properties, e.g. modulus