Scope:

The ASTM D4669 test method is important to determine the specific gravity of polyols. It defines a standard to control the quality and application of these polyols. It characterizes the polyols found in polyurethane products and is applicable for research purposes. It uses a digital density meter to calculate the specific gravity of polyols and many other liquids, which specifies their reliability and helps finalize their application. This specific gravity is important in viscosity conversions when moving from kinematic viscosity to absolute viscosity.

Procedure:

The apparatus for ASTM D4669 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. The sample is put in separate trials in the pycnometer that is then placed in a water 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. The specific gravity of polyols can also be determined by using a digital density meter.   

Specimen size:

In ASTM D4669, the specimen is taken in liquid form. For a pycnometer, the quantity of the sample is kept under 25 or 50 mL. 

Data:

The specific gravity at 25/25°C can be calculated 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 D4669 test method is important to determine the specific gravity of polyols. It defines a standard to control the quality and application of these polyols.