Influence of the Alkane Molar Distribution on the Physical Properties of Synthetic Waxes

The purpose of this paper is to compare the structure and the mechanical properties of several model mixtures exclusively constituted of pure linear alkanes so as to better understand the conditions in which disorder appears within real systems. The molar distribution of all the studied mixtures is of "normal logarithmic type", and the only statistical parameter varying from one mixture to the other is the standard deviation (sigma) of the distribution. This work was carried out by means of X-ray diffraction, differential scanning calorimetry (DSC), and dynamical mechanical analysis (DMA) according to temperature. The obtained results show that the number of crystallized phases increases with the standard deviation and that the structural evolution versus temperature of the mixtures also depends on this statistical parameter. With regard to the mechanical properties, the results of the dynamic mechanical analyses show that the storage modulus (E') and the loss factor (tan delta) are also affected by the standard deviation of the distribution.