The thermal history and in particular the mixing dump temperature is a parameter of paramount importance in mixing rubber and silica with a silane coupling agent in order to achieve proper silanization of silica and to avoid premature scorch reactions. In this work, the influence of mixing dump temperature on the performance of silica reinforced Natural Rubber (NR) is investigated. The investigation also includes the effect of non-rubber constituents, primarily proteins in NR, by using deproteinized Natural Rubber (DPNR) and synthetic polyisoprene (IR). The vulcanization properties and rubber-to-filler interactions of silica reinforced NR in presence and absence of a silane coupling agent are highlighted. With increasing mixing dump temperature, the silanization reaction between silica and silane coupling agent proceeds further. At sufficiently high dump temperature, filler-filler interactions in the NR-silica compounds are reduced and silica-rubber interaction improved as evidenced by a drop in the Payne effect and increment in chemically bound rubber. It is demonstrated that NR and IR compounds mixed till above the optimum dump temperature exhibit cure reversion and reduction in tensile properties. On the other hand, DPNR-silica vulcanizates show slightly more constant physical properties.
|Title of host publication||Proceedings of the 182nd American Chemical Society Rubber Division Meeting, Vol. 1|
|Place of Publication||Cincinnati, Ohio USA|
|Publisher||Curran Associates Inc.|
|Publication status||Published - 9 Oct 2012|
|Event||182nd Technical Meeting ACS Rubber Division 2012 - Cincinnati, United States|
Duration: 9 Oct 2012 → 11 Oct 2012
Conference number: 182
|Conference||182nd Technical Meeting ACS Rubber Division 2012|
|Period||9/10/12 → 11/10/12|
Sarkawi, S. S., Dierkes, W. K., & Noordermeer, J. W. M. (2012). Reinforcement of natural rubber by precipitated silica: the influence of processing temperature. In Proceedings of the 182nd American Chemical Society Rubber Division Meeting, Vol. 1 (pp. 925-960). Cincinnati, Ohio USA: Curran Associates Inc..