{"references": ["S. N. Maiti, V. Agarwal, A. K. Gupta, \"Melt rheological behavior of\nPP\u2013SAN blend,\" J. Appl. Polym. Sci., vol. 43, pp. 1891-1900, 1991.", "A. C. Patel, R. B. Brahmbhatt, B. D. Sarawade, S. Devi, \"Morphological\nand mechanical properties of PP/ABS blends compatibilized with PP-gacrylic\nacid,\" J. Appl. Polym. Sci., vol. 81, pp. 1731-1741, 2001.", "H. G. Lee, Y.-T. Sung, Y. K. Lee, W. N. Kim, H. G. Yoom, H. S. Lee,\n\"Effects of PP-g-MAH on the mechanical, morphological and\nrheological properties of polypropylene and poly(acrylonitrilebutadiene-\nstyrene) Blends,\" Macromol. Research, vol. 17, pp. 417-423,\n2009.", "P. Xiang-Fang, P. Jun, X. Xiao-li, T. Lih-Sheng, \"Effect of organoclay\non the mechanical properties and crystallization behaviors of injectionmolded\nPP/ABS/montmorillonite nanocomposites,\" ANTEC, pp. 1105-\n1108, 2009.", "C. Markin, H. L. Williams, \"Polypropylene/ABS terpolymer blends.\nmixing and mechanical properties,\" J. Appl. Polym. Sci., vol. 25, pp.\n2451-2466, 1980.", "A. K. Gupta, A. K. Jain, S. N. Maiti, \"Studies on binary and ternary\nblends of polypropylene with ABS and LDPE. I. Melt rheological\nbehavior,\" J. Appl. Polym. Sci., vol. 38, pp. 1699-1717, 1989.", "A. K. Gupta, A. K. Jain, B. K. Ratman, S. N. Maiti, \"Studies on binary\nand ternary blends of polypropylene with ABS and LDPE. II. Impact\nand tensile properties,\" J. Appl. Polym. Sci., vol. 39, pp. 515-530, 1990.", "Q. Shu, X. Zou, W. Dai, Z. Fu, \"Formation of \u03b2-iPP in isotactic\npolypropylene/acrylonitrile\u2013butadiene\u2013styrene blends: Effect of resin type, phase composition, and thermal condition,\" J. Macromol. Sci., Part\nB: Physics, vol. 51, pp. 756\u2013766, 2012.", "C. Wang, Z. Zhang, Y. Du, J. Zhang, K. Mai, \"Effect of acrylonitrile\u2013\nbutadiene\u2013styrene copolymer (ABS) on \u03b2-nucleation in \u03b2-nucleated\npolypropylene/ABS blends,\" Polym. Bull., vol. 69, pp. 847\u2013859, 2012.\n[10] M. Frounchi, R. P. Burford, \"State of compatibility in crystalline\npolypropylene/ABS amorphous terpolymer thermoplastic blends. Effect\nof styrenic copolymers as compatibilisers,\" Iran. J. Polym. Sci. and\nTechnol., vol. 2, pp. 59-68, 1993.\n[11] E. Arroyo, C. Guerrero, V. Gonzalez, \"Blends of ABS and iPP,\"\nANTEC\n[12] Y. K. Lee, J. B. Lee, D. H. Park, W. N. Kim, \"Effects of accelerated\naging and compatibilizers on the mechanical and morphological\nproperties of polypropylene and poly(acrylonitrile-butadiene-styrene)\nblends\", J. Appl. Polym. Sci., vol. 127, pp. 1032-1037, 2013.\n[13] C. K. Kum, Y.-T. Sung, Y. S. Kim, H. G. Lee, W. N. Kim, H.S. Lee,\nH.G. Yoon, \"Effects of compatibilizer on mechanical, morphological,\nand rheological properties of polypropylene/poly(acrylonitrilebutadiene-\nstyrene) blends,\" Macromol. Research, vol. 15, pp. 308-314,\n2007.\n[14] A. C. Patel, R. B. Brahmbhatt, S. Devi, \"Mechanical properties and\nmorphology of PP/ABS blends compatibilized with PP-g-2-HEMA,\" J.\nAppl. Polym. Sci., vol. 88, pp. 72-78, 2003.\n[15] Y. Wang, Q. Zhang, Q. Fu, \"Compatibilization of immiscible\npoly(propylene)/polystyrene blends using clay\", Macromol. Rapid\nCommun., vol. 24, issue 3, pp. 231-235, 2003.\n[16] B. Chen, J.R.G. Evans, \"Mechanical properties of polymer-blend\nnanocomposites with organoclays: Polystyrene/ABS and high impact\npolystyrene/ABS\", J. Polym. Sci., Part B: Polym. Phys., vol. 49, issue 6,\npp. 443-454, 2011.\n[17] C. C. Ibeh, N. Baker, D. Lamm, S. Wang, D. Weber, J. Oplonitnik,\nANTEC conference proceedings 5, pp. 1893-1897, 2005.\n[18] Y. T. Sung, Y. S. Kim, Y. K. Lee, W. N. Kim, H. S. Lee, J. Y. Sung, H.\nG. Yoon, \"Effects of clay on the morphology of poly(acrylonitrilebutadiene-\nstyrene) and polypropylene nanocomposites,\" Polym. Eng.\nSci., vol. 47, pp. 1671-1677, 2007.\n[19] B. Panda, A. R. Bhattacharyya, A. R. Kulkarni, \"Ternary polymer\nblends of polyamide 6, polypropylene and acrylonitrile-butadienestyrene:\nInfluence of multi walled carbon nanotubes on phase\nmorphology, electrical conductivity, and crystallization,\" Polym. Eng.\nSci., vol. 51, pp. 1550-1563, 2011.\n[20] R. A. Khare, A. R. Bhattacharyya, A. R. Kulkarni, \"Melt-mixed\npolypropylene/acrylonitrile-butadiene-styrene blends with multiwall\ncarbon nanotubes: Effect of compatibilizer and modifier on morphology\nand electrical conductivity,\" J. Appl. Polym. Sci., vol. 120, pp. 2663\u2013\n2672, 2011.\n[21] R. A. Khare, A. R. Bhattacharyya, A. R. Kulkarni, M. Saroop, A.\nBiswas, \"Influence of multiwall carbon nanotubes on morphology and\nelectrical conductivity of PP/ABS blends,\" J. Polym. Sci.: Part B:\nPolym. Physics, vol. 46, pp. 2286\u20132295, 2008.\n[22] M. Milani, R. Ouijada, N. R. S. Basso, A. P. Graebin, G. B. Galland,\n\"Influence of the graphite type on the synthesis of\npolypropylene/graphene nanocomposites,\" J. Polym. Sci., Part A:\nPolym. Chem.,vol. 50, pp. 3958-3605, 2012.\n[23] C. I. Ferreira., C. Dal Castel., M. A. S. Oviedoc, R. S. Mauler.,\n\"Isothermal and non-isothermal crystallization kinetics of\npolypropylene/exfoliated graphite nanocomposites,\" Thermochim. Acta,\nvol. 553, pp. 40\u2013 48, 2013.\n[24] P. Steurer, R. Wissert, R. Thomann, R. M\u00fclhaupt, \"Functionalized\ngraphenes and thermoplastic nanocomposites based upon expanded\ngraphite oxide,\" Macromol. Rapid Commun., vol. 30, pp. 316\u2013327,\n2009.\n[25] S. Zhao, F. Chen, C. Zhao, Y. Huang, J.-Y. Dong, C. C. Han,\n\"Interpenetrating network formation in isotactic polypropylene/graphene\ncomposites,\" Polymer, vol. 54, pp. 3680-3690, 2013.\n[26] G. Gedler, M. Antunes, V. Realinho, J. L. Velasco, \"Novel\npolycarbonate-graphene nanocomposite foams prepared by CO2\ndissolution,\" IOP Conf. Ser.: Mater. Sci. Eng., vol. 31, 2012.\n[27] G. Gedler, M. Antunes, V. Realinho, J. L. Velasco, \"Thermal stability of\npolycarbonate-graphene nanocomposite foams,\" Polym. Degrad. Stab.,\nvol. 97, pp. 1297-1304, 2012.\n[28] P. Song, L. Liu, S. Fu, Y. Yu, C. Jin, Q. Wu, Y. Zhang, Q. Li, \"Striking\nmultiple synergies created by combining reduced graphene oxides and\ncarbon nanotubes for polymer nanocomposites,\" Nanotechnology, vol.\n24, no. 12, 2013.\n[29] B. Shen, W. Zhai, M. Tao, D. Lu, W. Zheng, \"Chemical\nfunctionalization of graphene oxide toward the tailoring of the interface\nin polymer composites,\" Compos. Sci. Technol., vol. 77, pp. 87-94,\n2013.\n[30] S. V.Polschikov, P. M. Nedorezova, A. N. Klyamkina, A. A. Kovalchuk,\nA. M. Aladyshev, A. N. Shchegolikhin, V. G. Shevchenko, V. E.\nMuradyan, \"Composite materials of graphene nanoplatelets and\npolypropylene, prepared by in situ polymerization,\" J. Polym. Sci., vol.\n127, issue 2, pp 904-911, Jan. 2013.\n[31] H. J. Park, J. Meyer, S. Roth, V. Sk\u00e1kalov\u00e1, \"Growth and properties of\nfew-layer graphene prepared by chemical vapor deposition,\" Carbon,\nvol. 48, pp. 1088-1094, 2010.\n[32] M. E. Achaby, F. E. Arrakhiz, S. Vaudreuil, A. K. Qaiss, M. Bousmina,\nO. Fassi-Fehri, \"Mechanical, Thermal, and Rheological Properties of\nGraphene-Based Polypropylene Nanocomposites Prepared by Melt\nMixing,\" Polym.Compos., vol. 33, issue 5, pp. 733-744, May 2012.\n[33] C. Heo, H.-G. Moon, C.-S. Yoon, J.-H. Chang, \"ABS Nanocomposite\nfilms based on functionalized-graphene sheets\", J. Appl. Polym. Sci.,\nvol. 124, pp. 4663\u20134670, 2012.\n[34] M. Milani, D. Gonz\u00e1lez, R. Ouijada, N. R. S. Basso, M. L. Cerrada, D.\nAzambuja, G. B. Galland, \"Polypropylene/graphene nanosheet\nnanocomposites by in situ polymerization: synthesis, characterization\nand fundamental properties,\" Comp. Sci. Technol., vol. 84, pp. 1-7,\n2013.\n[35] V. G. Shevchenko, S. V. Polschiko, P. M. Nedorezova, A. N.\nKlyamkina, A. N. Shchegolikhin, A. M. Aladyshev, V. E. Muradyan,\n\"In situ polymerized poly(propylene)/graphene nanoplatelets\nnanocomposites: Dielectric and microwave properties,\" Polymer, vol.\n53, pp. 5330-5335, 2012.\n[36] J.-Z. Xu, C. Chen, Y. Wang, H. Tang, Z.-M. Li, B. S. Hsiao, \"Graphene\nNanosheets and Shear Flow Induced crystallization in isotactic\npolypropylene nanocomposites,\" Macromolecules, vol. 44, pp. 2808\u2013\n2818, 2011.\n[37] J.-E. An, G. W. Jeon, Y. G. Jeong, \"Preparation and properties of\npolypropylene nanocomposites reinforced with exfoliated graphene\",\nFibers Polym., vol. 13, no. 4, pp 507-514, 2012.\n[38] P. Song, Z. Cao, Y. Cai, L. Zhao, Z. Fang, S. Fu, \"Fabrication of\nexfoliated graphene-based polypropylene nanocomposites with\nenhanced mechanical and thermal properties\", Polymer, vol. 52, pp.\n4001-4010, 2011.\n[39] J. Dai, Y. Shen, J.-H. Yang, T. Huang, N. Zhang, Y. Wang,\n\"Crystallization and melting behaviors of polypropylene admixed by\ngraphene and \u03b2-phase nucleating agent\", Colloid Polym. Sci., pp. 1-11,\n2013.\n[40] J. Ma, Q. Meng, I. Zaman, S. Zhu, A. Michelmore, N. Kawashima, C. H.\nWang, H.-C. Kuan, \"Development of polymer composites using\nmodified, high-structural integrity graphene platelets,\" Comp. Sci.\nTechnol., vol. 91, pp. 82\u201390, 2014.\n[41] J.-B. Chen, J.-Z. Xu, H. Pang, G.-J. Zhong, L. Xu, H. Tang, J.-H. Tang,\nZ.-M. Li, \"Crystallization of Isotactic Polypropylene inside Dense\nNetworks of Carbon Nanofillers\", J. Appl. Polym. Sci., vol. 131, issue 6,\n2014."]}

In the present study, the incorporation of graphene into blends of acrylonitrile-butadiene-styrene terpolymer with polypropylene (ABS/PP) was investigated focusing on the improvement of their thermomechanical characteristics and the effect on their rheological behavior. The blends were prepared by melt mixing in a twin-screw extruder and were characterized by measuring the MFI as well as by performing DSC, TGA and mechanical tests. The addition of graphene to ABS/PP blends tends to increase their melt viscosity, due to the confinement of polymer chains motion. Also, graphene causes an increment of the crystallization temperature (Tc), especially in blends with higher PP content, because of the reduction of surface energy of PP nucleation, which is a consequence of the attachment of PP chains to the surface of graphene through the intermolecular CH-π interaction. Moreover, the above nanofiller improves the thermal stability of PP and increases the residue of thermal degradation at all the investigated compositions of blends, due to the thermal isolation effect and the mass transport barrier effect. Regarding the mechanical properties, the addition of graphene improves the elastic modulus, because of its intrinsic mechanical characteristics and its rigidity, and this effect is particularly strong in the case of pure PP.