1 3 mm long and wide the same procedure was used for the preparation of polypropylene composites ph 013 and ph 2610 with a mixture of mineral reinforcements ta1 or ta2 or ta3 and natural reinforcement in a proportion of 40 by weight of total reinforcement as summarized in table 6 the composites shown in table 6 comprise polypropylene antioxidant and reinforcements wherein the percentage of polypropylene includes the antioxidant the tests carried out to verify the mechanical and thermal properties of the polypropylene composites with natural reinforcement as well as of the polypropylene composites with traditional mineral reinforcements and the polypropylene composites with mixtures of mineral reinforcement and natural reinforcement were the following tensile tests according to astm standard d 638 to determine young 39 s modulus in megapascals mpa izod impact tests at u2212 20 u00b0 c according to astm standard d 256 to determine the energy absorbed on impact in j m density tests according to astm standard 679 in g cm 3 thermal tests by differential scanning calorimetry that allows the degree of crystallinity to be obtained as a percentage the results obtained from the above mentioned tests with the polypropylene composites with natural eggshell reinforcements traditional mineral reinforcements and mixtures of mineral reinforcement and natural reinforcement corresponding to 31 samples are summarized in table 5 according to the results shown in tables 5 and 6 the tests carried out with the polypropylene composites with natural reinforcement traditional mineral reinforcements and or mixtures of mineral reinforcement and natural reinforcement have proved the competitiveness of the.