Scope:

The ASTM D1621 test method determines the compressive properties of rigid cellular plastics and specifies their behavior. The help of a load-deformation curve determines stress and modulus of elasticity. Yield point, strain, deformation, displacement, and gauge length are also measured. The test method provides data for research and aids in development and quality control, along with specifying the applications of these materials. In this way, this test method defines the standard for preparing and testing rigid cellular materials, especially plastics.

Procedure:

The apparatus used in ASTM D1621 consists of a testing machine, load measurement system, compression platens, displacement measurement system, and direct compression platen displacement system. A micrometer dial gauge is used to measure the specimen size. Then the sample is carefully aligned between the compression platens. The displacement, thickness, yield point, and deformation are detected by compressing the specimen. All these properties help define the applications of rigid cellular materials, especially plastics.

Specimen size:

As per ASTM D1621, the test specimen is square or circular with a minimum and maximum area of 25.8 cm.sq and 232 cm.sq respectively. The minimum height is 25.4 mm, and the full size should not exceed the width or diameter of the specimen.

Data:

In ASTM D1621, the apparent modulus (E_c ) can be calculated as:

E_c ꞊ WH/AD           

Where  (W=load, H= height, A=Area, D=Deformation) 

Conclusion:

The ASTM D1621 test method determines the compressive properties of rigid cellular plastics and specifies their behavior.