Design and preparation of novel silicon rubber with homogeneous crosslinking network and its application in high-performance SR/EPDM blend

Due to the low intermolecular force, silicone rubber (SR) processes weak mechanical properties and it’s difficult to blend with other conventional rubbers, which limits its application. Herein, a series of novel SRs with evenly distributed and different types of crosslinking groups were synthesized and cured to SR blends. The novel SRs promote the uniform distribution of crosslinking points during vulcanization, which contributes to the increase in both tensile strength and elongation at break. Besides, the introduction of different types of crosslinking groups decreases vulcanization speed as well as increases the flexibility of the bridge between two crosslinked polymer chains, resulting in the elongation at break as high as 1143%, which is twice higher than commercial SR. The novel SRs were subsequently blended with ethylene-propylene-diene rubber (EPDM) to prepare high-performance blends. Compared with the commercial SR/EPDM blend, the matching vulcanization resulted in an increase in the tensile stress and elongation at break by 27.6% and 35.3%, respectively. In addition, dielectric strength increases from 34.2 to 40.8 kV/mm for SEP-VCH. Our work provides a new strategy to prepare SR with high mechanical properties and improve the properties of SR/EPDM blend without the addition of a compatibilizer, thus extending the application of SR.