JOURNAL OF COMPOSITE MATERIALS Article Effects of EVA-g-MA and EVACO compatibilizers/tougheners on morphological and mechanical properties of PP/EVA/HNT blend polymer nanocomposites Salih Dog ˘u, Emre Tekay and Sinan ¸ Sen Abstract A series of polypropylene (PP)/poly(ethylene-co-vinyl acetate) (EVA) blend nanocomposites was produced by utilizing different amounts of organophilic halloysite nanotube (Org-HNT) and EVA-based compatibilizers/tougheners. They were prepared by using either only EVA elastomer or using EVA with the compatibilizers which are maleic anhydride grafted EVA (EVA-g-MA) and poly(ethylene-vinyl acetate-carbon monoxide) (EVACO) as well as maleic anhydride grafted PP (PP- g-MA). The morphology–mechanical property relationship was investigated as a function of nature of the compatibilizer and the amount of aluminosilicate nanotube/compatibilizer. The composites prepared without using the EVA-based compatibilizers in all nanotube loading degrees (1%, 3%, 5%) exhibited nanotube aggregates as evidenced by scanning electron microscope analyses. On the other hand, EVA-g-MA and EVACO provided a good dispersion of HNTs at both PP–EVA interface and in the PP matrix. The use of compatibilizers together with 3% Org-HNTresulted in PP/EVA blend nanocomposites with higher tensile modulus and toughness when compared to PP/EVA blend. Particularly, EVACO compatibilizer having highly polarcarbonyl group at its backbone provided the highest toughness and Young’s modulus as well as impact resistance for the 3% Org-HNT loaded nanocomposite while retaining the yield strength as an indication of a good balance between stiffness/toughness. Keywords Polypropylene, nanocomposites, tensile properties, poly(ethylene-vinyl acetate-carbon monoxide) compatibilizer, halloy- site nanotube, morphology Introduction Polypropylene (PP) is a low-cost, lightweight and ver- satile thermoplastic that is compatible with many pro- cessing methods and is used in many commercial applications. The two most important disadvantages of PP are that it does not contain any polar group in the polymer main chain resulting in poor interaction with other polar materials and it also exhibits low impact resistance at low temperatures. The latter restricts the use of PP in many engineering applica- tions. 1 One of the approaches used to improve the mechanical properties of PP is to prepare the PP blends with elastomeric materials. 2 Ethylene-propylene diene rubber 3,4 and styrene-butadiene-styrene block copolymer, 5 styrene-ethylene-butylene-styrene 6 and poly(ethylene-co-vinyl acetate) (EVA) 7 elastomers are the most commonly used polymers to increase the impact resistance of PP. Another approach used to improve the mechanical properties of PP is to reinforce PP with inorganic fillers such as talc, mica, clay, glass fibre and silica nanopar- ticles. 8,9 In the literature, there are relatively few studies in which aluminosilicates with the tubular structure are Department of Polymer Engineering, Yalova University, Turkey Corresponding author: Sinan ¸ Sen, Department of Polymer Engineering, Yalova University, Yalova 77200, Turkey. Email: sinans@yalova.edu.tr Journal of Composite Materials 0(0) 1–21 ! The Author(s) 2019 Article reuse guidelines: sagepub.com/journals-permissions DOI: 10.1177/0021998319893423 journals.sagepub.com/home/jcm