Radiation crosslinked blends based on an ethylene octene copolymer (EOC) and polydimethyl siloxane (PDMS) rubber with special reference to the optimization of processing parameters

Abstract

This work focuses on the preparation of blends based on an ethylene octene copolymer (EOC) and polydimethyl siloxane rubber (PDMS), at a particular blend ratio through a melt mixing technique with special reference to the optimization of processing parameters. The optimized blend has been elastically reinforced through a dry curing process (radiation crosslinking) and the physico-mechanical properties were analyzed. It has been found that the rotor speed and the blending temperature of the mixer play very significant roles in controlling the strength properties of the blends, while the time of mixing has less effect on the ultimate properties as compared to the other parameters. It is also found that the viscosity ratio plays an important role in the development of the morphology of the blends. The droplet matrix morphology of the blends, particularly the size of the PDMS domains and the distribution of these domains in the EOC matrix have a remarkable influence on the overall mechanical strength properties of the blends. Through the optimization of the processing parameters, the size of the PDMS rubber domains is effectively decreased from 1.3 μm to 0.6 μm. This reduction in the particle size enhances the tensile strength by about 14.3%. It is found that radiation crosslinking at a radiation dose of 75 kGy improved the tensile strength by about 13% as compared to the optimized blend. All the irradiated blends have higher volume resistivity as compared to the optimized non irradiated blend.