The objective of this paper is to evaluate the thermal properties such as stability, degradation and glass transition temperature of Natural Rubber (NR) blended with Nitrile Butadiene Rubber (NBR) at 80:20 concentrations. Thermogravimetric Analysis (TGA) has been successfully exploited to study the thermal properties of the blend in the temperature range of room temperature to 600 °C. The temperature increased in the steps of 20 °C/min, whereas the heating rate is varied dynamically when the weight change occurs. In addition, the studies on the power loss per minute were also carried out using Differential Scanning Calorimetry (DSC) under Argon (Ar) atmosphere with the Ar flow being 80.0 mL/min. The heating rate is 10 °C/min. The DSC studies were carried out in the temperature range of – 125 °C to +200 °C. Scanning Electron Microscopy (SEM) has been used to study the surface morphology of NR/NBR blend.

The blending of different rubber materials is the most promising and feasible approach (Rajendran et al., 2002a; and 2002b) and has technically become important material. Although a large number of combinations of rubber for blending are possible, there are a few that lead to totally miscible systems (Hofmann et al., 1984, p. 753; and Chung and Hamed, 1989, p. 367). It was found that the adhesion between uncrossed link layers of isoprene rubber and Nitrile Butadiene Rubber (NBR) is rate and temperature dependent. The compatibility of rubber blends was examined. The technique of blending has been widely adopted for achieving a unique balance of properties to generate high-performance materials for specific applications. Since these blends find wide applications as insulating materials in electrical appliances due to their low dielectric loss; dielectric analysis of rubber materials and their blends might provide useful information. The thermal stability as well as the thermal and electrical properties of rubber materials, which are affected by the temperature changes play an important role in many industrial applications such as wire and cable insulation, heat shrinkable materials, rubber tyres and electronic packaging (Baird, 1977; Becker et al., 1979; Ota, 1981; and Uda et al., 1990). Finished products are found in the marketplace as injection or transfer molded products like seals and grommets, extruded hose or tubing, calendered sheet goods, viz., floor mats and industrial belting or various sponge articles.

The mechanical blending of two rubber materials is the simplest means to obtain a variety of physical properties from the constituent rubber materials. Natural Rubber (NR) is blended with NBR to enhance the oil resistance of NR and thermal resistance properties of NBR. Clarke et al. (2001) have carried out experiments to test the hypothesis using carbon black as the filler in blends of NR and NBR with an acrylonitrile content of 45%. Blends of NR/NBR (70/30) were prepared in an internal mixer with varying amounts of carbon black. The dramatic decrease in the domain size on addition of carbon black was nonetheless lower than that predicted.

Physics Journal, Thermal Characterization, Nitrile Butadiene Rubber, Scanning Electron Microscopy, Industrial Applications, Carbon Black, Differential Scanning Calorimetry, Differential Thermogravimetric Analysis, DTGA, Electric Goods, Rubber Materials, Surface Morphology.