جستجوی مقالات مرتبط با کلیدواژه « Swelling resistance » در نشریات گروه « مهندسی شیمی، نفت و پلیمر »

Better understand the mechanism of reinforcing produced by spherical nanoparticles in this rubber will help significantly in achieving engineering products. In this paper, the effect of nano-calcium carbonate was investigated in the range 0-20 phr on the properties of natural rubber (NR) and nitrile rubber (NBR) including cure rheometry (scorch time, cure time, max and min torque and different torque), tensile behavior, hardness and swelling resistance. Various experimental results show that changes many properties by addition of nano-CaCO3 are quite similar in the two rubbers and the optimal amount of nano-CaCO3 in both rubbers is 15 phr which by higher content, will be loss mechanical properties as well as other engineering properties. Significant improvement in mechanical properties without reducing the elastic properties of the rubber compounds is reason of the effectiveness of the enhanced mechanical properties of used nanoparticles in this study. Effect of calcium carbonate nanoparticles in change of Gibbs free energy is remarkable in natural rubber and reflects the greater tendency of solvent to natural rubber than nitrile rubber. Better dispersion of nanoparticles of calcium carbonate in nitrile rubber and also stronger interactions in interface of nano-CaCO3 and nitrile rubber with Kraus plotting was concluded.

The transport properties of liquids and gases through polymeric materials play a very important role in some areas of industrial applications. In this study, natural rubber (NR)/CaCO3 composites were prepared by melt mixing method. By equilibrium swelling test, the transport process of toluene in the prepared natural rubber composites was investigated. The diffusion and transport of toluene through calcium carbonate-filled natural rubber composites have been studied in the temperature range 25–45°C. The diffusion of toluene through these composites was studied with special reference to the effect of filler concentration and temperature. The transport coefficients such as diffusion, permeation and sorption coefficients were estimated from the swelling data. To find out the mechanism of diffusion in prepared composites, the results of swelling studies were applied to an empirical equation. In these composites, diffusion is approximately based on Fickian diffusion mechanism and by increases in temperature; diffusion mechanism is more close to Fickian mechanism. Increase of filler content in composite would result in decreased ultimate swelling and slower diffusion rate of solvent. The diffusion rate, diffusion coefficient and the permeability increased by temperature. The study of the diffusion of toluene through filled natural rubber indicated that the concentration of filler plays an important role in the diffusion, sorption and permeation coefficients. Also interfacial interactions in NR composites were checked by dynamic-mechanical analysis. The microstructure and dispersion of calcium carbonate particles in natural rubber matrix were studied by field emission scanning electron microscopy (FE-SEM). In general, the results of swelling tests, dynamic-mechanical analysis and FE-SEM images show that the optimized value of filler in NR composites is equal to 10 phr calcium carbonate