ASTM D4659 Determination of Specific Gravity of Isocyanates

Scope:

The ASTM D4659 test method is important to determine the specific gravity of isocyanates. It defines a standard to control the quality and application of these isocyanates. It characterizes the isocyanates found in polyurethane products and is applicable for research purposes. It uses a digital density meter to calculate the specific gravity of isocyanates and many other liquids, which specify their reliability and help finalize their application. 

Procedure:

The apparatus for ASTM D4659 testing consists of a pycnometer, thermometer, water bath, and analytical balance. The pycnometer is cleaned with a chromic acid cleaning solution and then washed with distilled water. Distilled water and the sample are poured in separate trials into the pycnometer and then placed in a bath. The thermometer is inserted into the pycnometer, and it is kept in the bath until it reaches equilibrium. The weight of the pycnometer is measured after its removal from the bath and is compared with the weight of the empty pycnometer. The weight of the sample is obtained by subtracting the weight of the empty pycnometer from the weight when it had a sample in it. While using a hydrometer, the before and after readings are compared to calculate specific gravity. 

Specimen size:

In ASTM D4679 testing, the specimen is taken in liquid form in a hydrometer cylinder of 25.4 mm diameter. For a pycnometer, the quantity of the sample is kept under 25 or 50mL. 

Data:

The specific gravity at 25/25°C can be calculated for ASTM D4679 testing with the help of a pycnometer as follows:

Specific gravity, 25/25°C ꞊ S/W
Where: S = sample used, g and
W = water in the pycnometer, g.

Conclusion:

The ASTM D4659 test method is important to determine the specific gravity of isocyanates.