The dielectric constants and loss factors of some natural waxes

Dielectric spectroscopy has been used to elucidate the essential structure of carnauba, montan and ouricuri waxes. By analysis of the dielectric constant and loss curves as determined over a broad range of temperature and frequency, it has been possible to establish the presence of permanent electric moments in the molecules and to determine that association through hydrogen bonding exists. Polar molecules may be roughly divided into two classes: amorphous and crystalline. In the former case the dielectric constant is seen to increase very slowly with temperature due to decreased viscosity and consequent ease of orientation of the molecules to an applied field. Above some temperature where the material is completely liquid, the dielectric constant decreases because of decreased density of polarizable molecules per unit volume and of the degree of orientation permitted as the thermal motion is increased. Maxima in the loss curves are caused by relaxation of polar groups and chain segments. Increased conductivity in the liquid accounts for rapid increase in the losses. A crystalline material, on the other hand, will show an abrupt rise in dielectric constant at the melting point. The waxes considered in the present study actually fall in an intermediate class which is crystalline but which has many properties like amorphous substances. In these substances, the molecules are capable of rotating in the solid state at temperatures well below the melting point without destroying the crystal structure.