Keywords: Thermoplastic elastomer; Poly propylene; Compatibilizer; Ground rubber tire In this research, it has been discussed about the preparation and investigation of mechanical properties of polypropylene/ground rubber tire blend. The Polypropylene grafted with maleic anhydride (PP-g-MA) and styrene ethylene butylene styrene grafted with maleic anhydride (SEBS-g-MA) as compatibilizer has been used in blending of components. The chemical modification of the ground rubber tire surface by acrylamide monomer was also used to improve interface between the components and enhance the mechanical properties of the blend. The effect of desired compatibilizers and surface chemical modification of ground rubber tire on the mechanical properties and morphology of the samples was analyzed. In order to determine the elastomer composition in the structure of ground rubber tire as well as weight fractions of its components, Pyrolysis-FTIR and TGA-DTG analysis was used, respectively. FTIR-ATR analysis was used to demonstrate the grafting of acrylamide monomer on the ground rubber tire surface. The tensile strength, young module, strain at break and impact strength was measured as the mechanical properties of the blend. The whole samples in the internal mixer were provided at 190 ?C and 60 rpm. The Blends of PP/GRT in the ratio of 90/10, 80/20, 70/30 and 60/40 were prepared. The results demonstrated that increasing the amount of tire powder causes tensile strength and young module to be decreased whereas strain at break and impact strength of the blends are increased. In binary blends PP/GRT, increasing GRT due to increasing elastomeric phase, module decreased and elongation of the blend increased whereas due to poor adhesion of the blend components, the tensile strength was reduced. Using of PP-g-MA compatibilizer improved the compatibility between ground rubber tire and polypropylene. Although the amount of the compatibility due to the brittle nature of the PP-g-MA and loss of mechanical properties during the process of grafting MA onto polypropylene is not significant. In this research, values of about 5% wt PP-g-MA increased the strain at break but increasing to amount of 10% wt led to decrease in toughness. SEBS-g-MA compatibilizer provided better effects of compatibility comparing PP-g-MA in the PP/GRT blend. By increasing SEBS-g-MA, the tensile strength and modulus of blends decreased but elongation at break was increased. In the SEBS-g-MA structure, rubber segments have great influence on the toughness of PP/GRT blends. Chemical modification of the tire particles surface by acrylamide monomer and preparing the reaction of acrylamide with maleic anhydride on the compatibilizer surface, led to increasing all the mechanical properties through reinforcement of the interface components. Increasing the compatibility in this method led to increase tensile strength, modulus and elongation at break comparing the unmodified blend composition containing either PP-g-MA or SEBS-g-MA. In samples containing compatibilizer PP-g-MA and SEBS-g-MA, the functionalization of tire particles led to improving about 12-14% in the tensile strength. Also, the elongation of the blends about 90-110% was improved. The impact strength of PP/GRT by increasing ground rubber tire due to the nature of the tire powder elasticity was increased. The presence of the compatibilizers PP-g-MA and SEBS-g-MA increased the impact strength of the blend in comparison to the blends without the compatibilizer. The impact strength in three components blends using tire particles functionalized by acrylamide was improved up to 20 %. Scanning electron microscopy images confirmed the effect of compatibilizers presence and the modification of tire particles surface on morphology of the blends and its mechanism in improving the mechanical properties.