High-Performance low-k Poly(dicyclopentadiene)-POSS nanocomposites achieved by frontal polymerization

Abstract

Low dielectric constant (low-k, k < 2.5) thermoset polymers play a crucial role in high-frequency communication technology and the microelectronic industry. However, existing low-k materials often suffer from time- and energy-consuming preparation procedures and have k values greater than 2.5. Herein, we present the frontal ring opening metathesis polymerization (FROMP) of dicyclopentadiene and phenyl-functionalized POSS bearing three and four norbornene groups (i.e., T7N3 and T8N4), enabling the rapid formation of high-performance low-k nanocomposites through a low energy consumption approach. The results reveal that T7N3 and T8N4 exhibit excellent compatibility with poly(dicyclopentadiene) (PDCPD) without adversely affecting the materials’ FROMP behaviors. Consequently, by increasing IC-POSS content, both the dielectric and comprehensive properties of PDCPD can be significantly enhanced while the influence of IC-POSS type remains limited. In particular, both PT7-40 (40 wt% of T7N3, k = 2.1) and PT8-40 (40 wt% of T8N4, k = 2.12) demonstrate the lowest k values; moreover, PT8-40 exhibits the highest dimensional stability (with a coefficient of thermal expansion of 79.3 ppm oC−1), glass transition temperature (188 °C), elastic modulus (2.32 GPa), yield strength (70.4 MPa), and hydrophobicity among all samples. By programming the front velocity, these materials can be processed into complex structures through a combination of FROMP and three-dimensional printing techniques. This work offers a facile and energy-efficient approach for preparing low-k materials with on-demand structures and properties.