Synthesis of Silphenylene-Containing Siloxane Resins Exhibiting Strong Hydrophobicity and High Water Vapor Barriers

Abstract

The novel phenylenedisilane, 1,4-bis(dimethoxyphenylsilyl)benzene (BDMPD), was successfully synthesized via the reaction between trimethoxyphenylsilane (TMPS) and a Grignard reagent originating from 1,4-dibromobenzene. In comparison to common Grignard reactions, this process was a facile one-pot method. 1H NMR spectroscopy, FT-IR measurements, and elemental analysis confirmed the predicted structure of BDMPD. In addition, vinyl-terminated polysiloxanes containing silphenylene units (VPSSP), which were hydrolytically copolymerized from BDMPD, TMPS, and divinyltetramethyldisiloxane, exhibited excellent thermal stabilities (T10%: 502 °C, Rw%: 76.86 beyond 700 °C) and suitable refractive indices (1.542). Furthermore, water contact angle and water vapor permeability tests confirmed that the fully cured siloxane resins containing VPSSP-based silphenylene units exhibited strong hydrophobicity (water contact angle: 119°) and superior water vapor barrier properties, thereby indicating their potential to serve as strong waterproof coatings for moisture-proof applications or as adhesives for use in immersed equipment.

Fabrication of UV–Curing Linalool–Polysiloxane Hybrid Films with High Refractive Index and Transparency

“…Phenyl groups in the main chain and in the pendant chain of polysiloxane endow various special properties, such as thermal stability and water vapor barrier property [1]. Besides, phenyl groups with high molar refraction enhance the refractive index of polysiloxane.…”

Moisture Barrier Properties of Silicone Rubber Surface Layers Fluorinated at Different Temperatures

“…Various approaches have been proposed to improve the moisture barrier properties of polymers in the packaging field [9][10][11][12], although few related studies have been reported in the field of high voltage insulation. For example, siloxane resins containing VPSSP (vinyl-terminated polysiloxanes containing silphenylene units)-based silphenylene units are found to have superior moisture barrier properties [9]. The incorporation of graphene oxide into silicone adhesive can improve moisture barrier properties as well as other properties desired for the application as a die-attach to light-emitting diodes [10].…”