Epoxidized natural rubber as a reinforcement modifier for silica‐filled nitrile rubber

Lime kiln dust (LKD) obtained from kraft chemical recovery systems by conversion of calcium carbonate (CaCO 3 ) back into calcium oxide (CaO) for reuse in the causticizing process, is mainly composed of CaCO 3 . A two-stage conventional mixing procedure was used to incorporate LKD into natural rubber (NR). For comparison purposes, four commercial fillers, stearic acid coated CaCO 3 , ground CaCO 3 , silica, and carbon black, were also used. The effect of these fillers on the curing characteristics and mechanical properties of NR materials at various loadings ranging from 0 to 60 phr were studied. The results indicate that the use of LKD filler resulted in a lower Mooney viscosity and shorter curing time in the NR materials. The incorporation of LKD into NR improved the Young's modulus and hardness but decreased the tensile strength and tear strength. However, LKD was better in processability than the commercial fillers. Scanning electron micrographs revealed that the morphology of the rubbers filled with reinforcing fillers, such as silica and carbon black, was finer and more homogeneous compared to the those of the rubbers filled with LKD and commercial CaCO 3 . The dispersion of LKD and commercial CaCO 3 fillers in the rubber matrix was discontinuous, which in turn, generated a weak structure compared with the reinforcing fillers. According to these observations, LKD could be used as a cheaper filler for NR materials where improved mechanical properties are not critical.

Section: Introductionmentioning

confidence: 99%

Application of lime kiln dust as a filler in the natural rubber industry

Arayapranee

Rempel

2010

“…TESPTs are the most efficient coupling agents for silica‐filled NR composites. It has been reported that the mechanical properties of silica‐filled ENR/NR blends without a coupling agent resulted in an excellent set of properties comparable to those of silica‐filled NR . Δ E ′ was significantly reduced by the presence of TESPT in silica‐filled composites; this increased the level of reinforcement and filler dispersion.…”

Section: Introductionmentioning

confidence: 96%

Exploring a highly dispersible silica–elastomer composite for tire applications

Manoharan

Naskar

2016

In this article, we provide an extensive analyses of various properties that are required for tire tread based on developed highly dispersible (HD) silica-filled epoxidized natural rubber composites. Silica in an HD form has become a staple filler in tire tread applications because of its inherent advantages. In this study, epoxidized natural rubber with 25 mol % epoxide (ENR 25) and natural rubber were mixed with two different types of HD silica for superior reinforcement. A standard tire tread formulation was used as the base compound. The magic triangle properties were conspicuously influenced by the viscoelastic characteristics of the vulcanizates. The introduction of polar rubber (ENR 25) into the HD silica greatly improved rheological, physicomechanical, bound rubber content, and dynamic mechanical properties, and this led to a better, fuel-efficient tire. We successfully achieved this, even in the absence of a silane coupling agent. ENR 25 played an imperative role in showing an extraordinary rubber-filler interactions and was primarily responsible for these observations. In this study, we explored the HD silica dispersion with transmission electron microscopy observations. Morphological studies revealed well-dispersed HD silica with the formation of a rubber-filler network.

“…Thus far, new interfacial modifiers have been developed from NR via an epoxidation reaction. George et al . applied epoxidized NR (ENR) as a reinforcement modifier for silica‐filled nitrile rubber (NBR).…”

Section: Introductionmentioning

confidence: 99%

Influence of chloroacetate group on physical properties of natural rubber and its interaction with fillers

Boochathum

Rongtongaram

2015

Filler–rubber composites were prepared by mixing chloroacetated natural rubber (CNR) with silica, carbon black (CB), or calcium carbonate using a two‐roll mill. The interactions between the CNR and fillers, including silica, carbon black, and calcium carbonate, were characterized based on glass transition temperature (Tg) and shear storage modulus (G′). The results showed that both the Tg and G′ values of the CNR‐Si composite were found to be higher than those of the CNR–CB and CNR–CaCO3 composites, indicating the existence of the CNR and silica interaction. The outstanding direct interaction between the CNR rubber matrix and silica without using a coupling agent was believed to be due to hydrogen bonds that formed between the hydroxyls of the silanol groups of silica and the carbonyls in the chloroacetate groups of CNR molecules. Moreover, it was also found that silica dispersed and distributed in the CNR matrix much better than in the natural rubber matrix. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43076.