3.1.2. Archimedes' Technique

The density value was also evaluated by the Archimedes' technique and found as 0.73 <sup>±</sup> 0.02 g/cm<sup>3</sup> . In both cases, ubim fiber density values (0.70 g/cm<sup>3</sup> for geometric and 0.73 g/cm<sup>3</sup> for Archimedes' technique) are among the lowest reported for NLFs and most commonly applied in reinforcing polymer composites such as flax, jute, sisal and cotton [7].

Using the Archimedes' technique it was not possible to precisely identify the difference in densities between thinner and thicker ubim fibers. This was due to the eventual penetration of gasoline (immersion liquid) into the fiber's open porosity. Nevertheless, the obtained value of 0.73 g/cm<sup>3</sup> is close to that found by the geometric method, 0.70 g/cm<sup>3</sup> , which in practice attests the mean value of ubim fiber density of 0.72 g/cm<sup>3</sup> .
