Polymer Technology Group

Density gradient column

The density gradient technique is an extremely accurate method for determining the density of solid specimens. A linear density gradient is obtained inside the 1m tall, conditioned, column by adopting a technique described in the standard method ASTM D1505. The density gradient ranges from the highest value at the bottom of the column to the lowest at the top. These limiting values are determined by the two solutions prepared to fill the column, whose densities are measured by a pycnometer or by a hydrometer. At least three floats having known densities are placed inside the column, so that the density at each position can be evaluated by a linear interpolation. The accuracy of the method can be better than 0.05%, density differences of 0.00001 can be measured. The picture reports the floats that we currently hold: the most common polymers can be accurately analyzed.

Graph floats density column
click on the image to enlarge