Novel high performance functionalized ladderlike polyphenylsilsesquioxane/bismaleimide hybrids with very good flame retardancy, thermal, and dimensional stability

Novel high performance hybrids (N-PPSQ/BDM/DBA) with very good flame retardancy, thermal, and dimensional stability as well as low dielectric constant and loss were developed, which consist of 4,4′-bismaleimidodiphenyl methane/2,2′-diallyl bisphenol A (BDM/DBA) resin and a novel functionalized ladderlike polyphenylsilsesquioxane (N-PPSQ). N-PPSQ was synthesized through the hydrolysis and condensation between phenyltrimethoxysilane and γ-aminopropyl triethoxysilane, and its structure was characterized by X-ray diffraction, nuclear magnetic resonance, gel permeation chromatography, and Fourier transform infrared. Compared with BDM/DBA resin, N-PPSQ/BDM/DBA hybrids show significantly improved integrated performances including remarkably reduced dielectric constant and loss, significantly improved flame retardancy, thermal, and dimensional stability, showing great potential for applications having harsh requirements in integrated performances. For example, in the case of the hybrid with 15 wt% N-PPSQ, its coefficient of thermal expansion in glassy and rubbery state are only about 49 and 42% of that of BDM/DBA resin, respectively; its limiting oxygen index increases from about 26.1–42.1%; while its dielectric loss is only about 87% of that of BDM/DBA resin at 1 kHz. These attractive improved properties are attributed to the variety in the cross-linked structure induced by the presence of N-PPSQ.