Purpose -The purpose of this paper is to evaluate the efficiency of organobentonite (OB) as reinforcing filler in acrylonitrile-butadiene rubber (NBR). The composites were prepared using different loadings of OB and studying in details their properties. A series of OB was modified using surfactant N-cetyl-N, N, N-trimethyl ammonium bromide (CTAB) with concentrations 0.5, 1 and 2 cation exchange capacity (CEC) of bentonite. Design/methodology/approach -The different bentonites were characterized using different analytical and spectro-photometric techniques, such as infra red, X-ray diffraction, thermogravimetric analysis and scanning electron microscopy, while rubber vulcanizate rheological, morphological, swelling and thermal properties were examined using different standard instrumental testing and methods. Findings -The study revealed that the modification of bentonite using CTAB showed significant enhancement on NBR properties, and the optimum filler loading was 12 phr for both 0.5CEC OB and 2CEC OB. These modified bentonites improved reinforcing properties to NBR vulcanizates. Also, results showed that composites exhibited remarkable improvements in tensile strength, elongation at break and hardness in the presence of modified bentonite and also an increase in thermal stability. Research limitations/implications -Na-B cannot be applied in rubber matrix without modification because it is incompatible with it.Practical implications -The modified bentonite is considered as efficient reinforcing filler which can replace other fillers because it has lower surface energy and improved intercalating behaviour in rubber matrix. Originality/value -These papered bentonites are cheap with relatively high purity, which make rubber/clay composites emerge as new class of material and can be used in different fields other than rubber.

Purpose This paper aims to study the role of organobentonite (OB) as a filler to improve the mechanical strength of styrene butadiene rubber (SBR). Organoclay was first prepared by modifying bentonite with different concentrations of N-cetyl-N, N, N-triethyl ammonium bromide. A series of SBR composites reinforced with OB were prepared using master-batch method. Design/methodology/approach The curing characteristics, mechanical properties, thermal behavior, dielectric properties and morphology of SBR/OB composites were investigated. Findings The elastic modulus and tensile strength of composites were increased by inclusion of OB, while the elongation at break was decreased, due to the increase in the degree of cross-linking density. Thermal gravimetric analysis revealed an improvement in the thermal stability of the composite containing 0.5 cation exchange capacity (CEC) OB, while the scanning electron micrographs confirmed more homogenous distribution of 0.5CEC OB in the rubber matrix. Also, SBR/0.5CEC OB showed low relative permittivity and electrical insulating properties. Research limitations/implications Bentonite has been recognized as a potentially useful filler in polymer matrix composites because of their high swelling capacity and plate morphology. Practical implications OB improves the cured rubber by increasing the tensile strength and the stiffness of the vulcanizate. Social implications Using cheap clay in rubber industry lead to production of low cost products with high efficiency. Originality/value The clay represents a convenient source because of their environmental compatibility. The low cost and easy availability make the modified clay used as fillers in rubber matrices, and the resultant composites can be applied in variety industrial of applications such as automobile industries, shoe outsoles, packaging materials and construction engineering.

Purpose The purpose of this paper is to evaluate the efficiency of commercial silica, silica fume-waste (SF) and modified silica fume-waste (mSF) as reinforcing filler in acrylonitrile-butadiene rubber (NBR) and ethylene propylene diene monomer (EPDM) through the mixing process of rubber. The composites were prepared using different loadings of silica fume and commercial silica in EPDM and NBR composites. Structural characterization of silica and SF was done using X-ray fluorescence and scanning electron microscopy (SEM). The surface of silica fume waste was modified using poly methyl methacrylate/butyl acrylate through emulsion polymerization to increase the interaction between silica and rubber, then consequently better dispersion in rubber matrix was obtained. The mSF waste was characterized using FT-IR spectra and transmission electron microscopy. Design/methodology/approach The investigated rubber mixes and vulcanizates were evaluated by measuring the curing characteristics, mechanical testing, thermogravimetric analysis and morphological studies (SEM). The mechanical properties of composites including tensile strength, elongation at break and modulus were estimated and analyzed. Findings The results revealed that the composites (NBR and EPDM) containing mSF as filler exhibited better rheological and mechanical properties compared to unmodified silica waste and commercial silica. The SEM analysis indicated that the mSF was homogeneously dispersed through the surface of NBR and EPDM composites. Also, results showed that (NBR and EPDM) composites exhibited remarkable improvements in tensile strength, elongation at break and hardness in the presence of mSF; they also showed an increase in the thermal stability. This means that the treatment of surface SF can improve its dispersion in rubber. Research limitations/implications Silica cannot be applied in rubber matrix without surface modification because of their incompatibility; their dispersion is not good without surface modification. Practical implications The modified silica surface is considered as effective reinforcing filler which can replace other fillers because of its lower surface energy and enhanced intercalating behavior in rubber. Social implications This study is just a start in establishing rubber projects with wide applications in the industry and providing a cheap local product while preserving the quality and that is the use of factory waste, which helps in protecting the environment from pollution. Originality/value mSF is cheap with relatively high purity, which make rubber/mSF composites appear as new grade of material that can be used in different media rather than rubber.

Petroleum oil derivatives have been used as a primary plasticizer in rubber compounding for tire applications. Due to the toxicity of petroleum oil derivatives, much attention has been paid to substituting them with renewable sources, aiming to produce more environmentally friendly rubber formulations. Although it harms the environment, it is also a nonrenewable resource that necessarily needs to be replaced. The present work aims to study the effects of vegetable and fruit oils as eco‐friendly processing oils for rubber products. The nitrile rubber (NBR) compounding contains a specific amount of vegetable‐based oil, linseed oil (LO), fruit‐based oil, Citrus volkameriana (CV), as alternatives to petroleum‐based oil, and dioctyl phthalate (DOP). The performance of NBR composites containing different processing aids was evaluated regarding the compounds' rheological, mechanical, and aging properties. To sum up, the study showed that substituting petroleum‐based oil with natural oil could substantially enhance the mechanical properties besides the other advantages such as decreased compound cost and increased cure rate.

Enhancement of the physicomechanical properties of rubber can be achieved by the incorporation of reinforcing fillers, such as clay. Cation-exchanged zeolites (CEZes) were prepared by exchanging the native Na+ ions with single inorganic cations (magnesium (Mg), zinc (Zn), or strontium) and/or double cations (Zn-Mg), then they were processed as reinforcing fillers in the two type of synthetic rubber, acrylonitrile-butadiene rubber (NBR) and styrene-butadiene rubber (SBR). Characterization of modified zeolite (Ze) was implemented using infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. The aim of this article is to study the influence of Ze and CEZe loadings on the rheometrical and physicomechanical properties of both NBR and SBR composites, also the thermogravimetric analysis was examined and the results were discussed. The results showed that the composites exhibited remarkable improvements in tensile strength, elongation at break, and hardness in the presence of CEZe and also an increase in thermal stability was reported.