This can be explained by the fact that
the diffusion of water in elastomers is not straight forward
by presence of hydrophilic materials (such as the hemp).
When the NR/hemp composite is exposed to moisture, the
hemp fibers undergo swelling. The high cellulose content
in hemp fiber (approximately 75 %) further contributes to
more water penetrating into the interface of composites
materials.The natural rubber is a hydrophobic material
and its water absorbability can be neglected . For
the same absorption time, composites having high-fiber
content exhibit high-water absorption because one of the
properties of these natural fibers (hemp) is hydrophilic
characteristic.