This project involves the characterization of mixtures of a synthetic polymer (polypropylene) with two kinds of waxes, which have been provided by two companies such as Repsol and Panreac. This will show us how the content of paraffin affects at different polymer characteristics observed in several trials and, thus, draw conclusions. It also aims to see what differences exist in the behavior of the polymer when is mixed with wax Panreac against is mixed with the wax Repsol. In this project we have studied the characteristics of six mixtures with increasing paraffin content for both Repsol and Panreac wax. These compounds were mixed in a "twin-screw extruder" after have calculated the quantities and mixing the components. To check the quality and homogeneity of the mixture and to make an estimation of the possible errors in characterizing of each mixture were measured density of each mixture and compared with the theoretical density. To measure the density has been used a "pycnometer". To study the properties of each mixture have been made five tests: - TGA (Thermogravimetric analysis): used to calculate the "decomposition temperature". - DSC (Differential scanning calorimetry) is used to measure the "melting temperature". - DMA (Dynamic mechanical analysis) is used to calculate the "glass transition temperature," called "Tg". - Calculation of viscosity with a "rheometer" as a result gives us the variation of viscosity with respect to the shear rate. - "Tensile test" calculated as the stress varying depending on the deformation. For testing DMA and tensile test was necessary to obtain several test pieces for each of the mixtures for both waxes, through which these trials have been performed. These specimens have been made in a "hot plate press".Ingeniería Industria