Blending of NR/BR/EPDM by reactive processing for tire sidewall applications. II. Characterization

• Published in: Journal of applied polymer science Vol. 103; no. 4; pp. 2547 - 2554
• Main Authors: Sahakaro, Kannika, Talma, Auke G., Datta, Rabin N., Noordermeer, Jacques W. M.
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 15.02.2007; Wiley
• Subjects: Applied sciences; blends; Composites; Exact sciences and technology; Forms of application and semi-finished materials; infrared spectroscopy; morphology; Polymer industry, paints, wood; reactive processing; Technology of polymers; tire sidewall; Reaction accelerator; Diene polymer; tire sidewall; Carbon black; Dispersion degree; Ternary mixture; Mechanical properties; reactive processing; Natural rubber; Dispersion reinforced material; Benzothiazole derivatives; Experimental study; Heterogeneous mixture; Structure processing relationship; Vulcanization; EPDM rubber; Vulcanizate; Butadiene polymer; Morphology; Sulfenamide; Sulfur; blends; infrared spectroscopy
• ISSN: 0021-8995; 1097-4628
• DOI: 10.1002/app.25113

Cure incompatibility in NR/BR/EPDM blends is a crucial problem, affecting blend properties. In a previous study, it was demonstrated that the mechanical properties of such blends can be significantly improved by utilizing a reactive processing technique, in which a pretreated EPDM is first prepared by incorporating all compounding ingredients in the EPDM and subsequent preheating, prior to crossblending with premasticated NR/BR. In the present article, the pretreated EPDM‐moieties are prepared using two different accelerators, N‐cyclohexyl‐2‐benzothiazole sulfenamide (CBS) and 6‐nitro MBTS. The latter was synthesized and applied for the purpose of IR characterization. The infrared (IR) spectra of the pretreated, extracted EPDM demonstrate absorption peaks associated with the IR absorption of the functional groups in the accelerator fragments, attached to the EPDM. NR/BR/EPDM (35/35/30) ternary blends are prepared by reactive mixing of the pretreated EPDM with CBS fragments attached with premasticated NR/BR on a two‐roll mill. Their blend morphological features are studied using the atomic force microscopy (AFM) and transmission electron microscopy (TEM) microscopic techniques, in comparison with those of blends prepared by a conventional straight mixing method. Both the tapping mode AFM phase images and TEM micrographs clearly show that reactive mixing leads to more homogeneous blends. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103:2547–2554, 2007