Relationships of the Degree of C=C Double Bond Conversion with the Dielectric Properties for SiO2/1,2‐PB/SBS/EPDM Composites Cured by Organic Peroxide

Abstract Polymer materials with low dielectric constant and dielectric loss play an indispensable role in high speed and stable signal transmission of electronic components. In this work, the SiO 2 / 1,2‐polybutadiene/ styrene‐butadiene‐styrene triblock copolymer/ ethylene‐propylene‐diene terpolymer (SiO 2 /1,2‐PB/SBS/EPDM) composites were prepared with different content of organic peroxide (bis (1‐(tert‐butyl peroxide)‐1‐methyl ethyl)‐benzene, BIPB). A high degree of crosslinking reaction may occur during the curing process. Attenuation total reflectance Fourier transformation infrared spectrometry (ATR‐FTIR) analysis showed that the degree of C=C conversion (DC) increased with the increase of BIPB content, and the dielectric constant of the composites was reduced. However, the dielectric loss decreased initially and subsequently increased. The excess initiators transform into impurities and increase the polarization and conductivity, resulting in a larger dielectric loss value of the composite. The combined results show that the DC value of 92.76 %, the dielectric constant of 3.37 and the dielectric loss of 0.0028 were obtained for the SiO 2 /1,2‐PB/SBS/EPDM composites containing 3 part‐by‐weight (pbw) BIPB. Furthermore, the composite had good thermal stability and superior mechanical properties.