Maleic-anhydride grafted EPM as compatibilising agent in NR/BR/EPDM blends

• Published in: European polymer journal Vol. 46; no. 4; pp. 754 - 766
• Main Authors: Zhang, H., Datta, R.N., Talma, A.G., Noordermeer, J.W.M.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.04.2010; Elsevier
• Subjects: Applied sciences; Compatibilisation; Exact sciences and technology; Maleic-anhydride grafted EPM; Mechanical properties; NR/BR/EPDM; Organic polymers; Physicochemistry of polymers; Properties and characterization; Rubber blends; Tire sidewall; Rubber blends; Maleic-anhydride grafted EPM; NR/BR/EPDM; Tire sidewall; Compatibilisation; Polymer blends; Dispersion degree; Mechanical properties; Natural rubber; Tensile property; Experimental study; Compatibilizer; Functional polymer; Heterogeneous mixture; Vulcanization; Ozone resistance; EPDM rubber; Vulcanizate; Fatigue strength; Butadiene polymer; Morphology; Mechanism of action; Chemical reactivity; Tear strength
• ISSN: 0014-3057; 1873-1945
• DOI: 10.1016/j.eurpolymj.2009.12.020

Maleic-Anhydride modified Ethylene-Propylene copolymer is used as compatibilising agent in blends of NR/BR/EPDM rubbers, to improve ozone-resistance. A more homogeneous phase morphology and much better carbon black distribution is obtained, which improves dynamic and mechanical properties. Incorporation of approximately 30 phr Ethylene–Propylene–Diene rubber (EPDM) into natural rubber (NR)/butadiene rubber (BR) is a means to achieve non-staining ozone resistance for tire sidewall applications. However, due to incompatibility of the elastomers and heterogeneous filler distribution in each of the rubber phases, the mechanical properties deteriorate. In the present work, maleic-anhydride modified EPM (MAH-EPM) is added as a compatibilising agent between NR/BR and EPDM. The addition of 5 phr of MAH-EPM results in significantly improved tensile and tear strength when compared to a straight NR/BR/EPDM blend. These improvements can mainly be attributed to a compatibilising effect of MAH-EPM, resulting in a more homogeneous phase distribution, but in particular a much better homogeneous carbon black distribution over the different rubber phases. In addition, ionic crosslinks are introduced into the blends by interaction of MAH-EPM with zinc oxide.