Synthesis of a Novel Bifunctional Epoxy Double-Decker Silsesquioxane: Improvement of the Thermal Stability and Dielectric Properties of Polybenzoxazine

Abstract

In this study a new type of bifunctional epoxy compound (DDSQ-EP) based on double-decker silsesquioxane (DDSQ) was synthesized by process of alkaline hydrolysis condensation of phenyltrimethoxysilane and corner capping reaction with dichloromethylvinylsilane, followed by epoxidation reaction of vinyl groups. The resultant structures were confirmed using Fourier transform infrared spectrometry, nuclear magnetic resonance spectrometry and time-of-flight mass spectrometry, respectively. The DDSQ-EP was incorporated into polybenzoxazine to obtain the PBZ/DDSQ-EP nanocomposites. The uniform dispersion of DDSQ-EP in the nanocomposites was verified by X-ray diffraction and scanning electron microscope. The reactions occurred during the curing of the composites and were investigated using infrared spectroscopy of segmented cures. Dynamic mechanical analysis and thermal gravimetric analysis indicated that the storage modulus, glass transition temperature and thermal stability of PBZ/DDSQ-EP were increased in comparison with pure benzoxazine resins. Assessment of dielectric properties demonstrated that the dielectric permittivity and dielectric loss of polybenzoxazine decreased slightly because of the addition of DDSQ-EP.

Novel Latent Catalyst for Ring-Opening Polymerization of 1,3-Benzoxazines Triggered by a Dual Ionic/Non-ionic Monomer Partnership

“…The benzoxazines have been obtained by using appropriate aminophenols in ring-closing reactions (ionic form) or Mannich condensation (neutral/non-ionic form). The resulting aminophenols and benzoxazines were characterized in solution and the solid state by elemental analysis, mass spectrometry, IR, and nuclear magnetic resonance spectroscopy ( 1 H, 13 C NMR, FTIR; see Supporting Information, Figures S2− S28), and for those obtained in a crystalline form suitable for diffraction analysis, by X-ray crystallography (see Supporting Information, Tables S1−S7). In the 1 H NMR spectrum, the diagnostic signals attributed to N−CH 2 −Ar and O−CH 2 −Ar methylene bridge protons for ionic form [ H,tBu Bx dC12 ]Cl, [ H,tBu Bx dMx ]Cl, [ dtBu Bx dMx ]Cl in CDCl 3 are shifted about 1 ppm in comparison to indicative bridged CH 2 protons for adequate neutral benzoxazine contained the same aryl core and substituents on a heterocyclic ring (Figure 5).…”

“…The 1 H, 13 C NMR spectra were obtained at 298 K using a Bruker Avance III 500 MHz spectrometer. The chemical shifts are given in ppm relative to the residual signals of the solvent (CDCl 3 , 1 H: 7.26 ppm, 13 C: 77.16 ppm and C 6 D 6 , 1 H: 7.16 ppm, 13 C: 128.06 ppm).…”

“…1 H NMR (500 MHz, CDCl 3 ): δ 7.28 (d, J = 2.3 Hz, 1H, ArH), 6.93 (d, J = 2.2 Hz, 1H, ArH), 5.56 (s, 2H, OCH 2 N), 5.15 (s, 2H, ArCH 2 N), 4.33 (dt, J = 13.7, 4.5 Hz, 2H, NCH 2 CH 2 ), 4.04 (dt, J = 9.6, 4.5 Hz, 2H, NCH 2 CH 2 ), 3.94 (t, J = 4.8 Hz, 4H, NCH 2 CH 2 ), 3.40 (s, 6H, OCH 3 ), 1.34 (s, 9H, tBu), 1.26 (s, 9H, tBu). 13 4.4.3. Synthetic Procedures of Neutral 1,3-Benzoxazines.…”

“…1 H NMR (500 MHz, CDCl 3 ): δ 7.24 (d, J = 2.4 Hz, 1H, ArCH), 6.89 (d, J = 2.4 Hz, 1H, ArCH), 4.97 (s, 2H, OCH 2 N), 4.15 (s, 2H, ArCH 2 N), 3.64 (t, J = 5.4 Hz, 2H, NCH 2 CH 2 ), 3.45 (s, 3H, OCH 3 ), 3.06 (t, J = 5.4 Hz, 2H, NCH 2 CH 2 ), 1.48 (s, 9H, tBu), 1.37 (s, 9H, tBu). 13…”

Construction of Fluorescent Conjugated Polytriazole Containing Double-Decker Silsesquioxane: Click Polymerization and Thermal Stability

“…Phenyltrimethylsilane, dichloro(chloromethyl)methylsilane, sodium hydroxide (NaOH), and 2-propanol were purchased from Sigma-Aldrich. Double-decker silsesquioxane-Na (DD-Na) was synthesized according to a previous procedure [ 22 , 45 , 46 , 47 ].…”