The purpose of this paper is to display the influence of isoalkanes on the structure and mechanical properties of waxes. This work was carried out by means of X-ray diffraction, differential thermal analyses, and dynamic mechanical analyses. Isoalkanes coming from an industrial wax were added in different quantities to a synthetic mixture of linear alkanes. The disorder generated by this addition was estimated by X-ray diffraction; it modifies the structural transformations versus temperature and therefore the mechanical properties. The branched chains of isoalkanes hinder the molecules motions, especially the rotation along the long axis. Thus, some phases usually formed at high temperature are not observed when increasing the temperature. With regard to the mechanical properties, the effect of the branched alkanes was studied using two industrial waxes with Gaussian distribution composition. The dynamic mechanical analyses have shown that the storage modulus (E′) is also affected by the isoalkane quantity.

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 (σ) 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 0 ) and the loss factor (tan δ) are also affected by the standard deviation of the distribution.

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