A low dielectric polysiloxane with hydro-oleophobicity and improved mechanical properties based on magnolol derivative crosslinker

Abstract

With the development of the microelectronics industry and the increasing concern for sustainability, there is an urgent need to prepare low dielectric materials from bio-based feedstocks. In this work, an allylated-magnolol (A-M) was synthesized as a crosslinker for fluorinated polymethylhydrosiloxane (F-PMHS) to obtain a low dielectric polysiloxane (M/F-PSO). M/F-PSO exhibited excellent dielectric properties with a dielectric constant of 2.73 and a dielectric loss of 0.0074 at 100 MHz. This was mainly attributed to the synergistic effect of the hard-polarization CF bond and the hindering molecular stacking structure of biphenyl. In addition, M/F-PSO had good hydro-oleophobicity (θwater = 108° and θglycol = 105°), which is brought about by the low surface energy CF3 and the rigid hydrophobic structure of A-M. The water absorption of M/F-PSO was only 0.13 % after 48 h immersion in deionized water. Owing to the introduction of rigid structure and good dispersion of A-M in F-PMHS, the tensile strength of M/F-PSO was up to 5.00 MPa, which is 432 % higher than that of pure polysiloxane (PSO). Moreover, the thermal stability of M/F-PSO was comparable to that of PSO, with an initial decomposition temperature (Td, 5%) as high as 440.30 °C. These results demonstrated the feasibility of introducing renewable bio-resource magnolol into polysiloxane to prepare low dielectric materials with excellent hydro-oleophobicity and mechanical properties.