Ortho-Imide and Allyl Groups Effect on Highly Thermally Stable Polybenzoxazine/Double-Decker-Shaped Polyhedral Silsesquioxane Hybrids

Abstract

We synthesized double-decker silsesquioxane (DDSQ)-functionalized benzoxazine (BZ) monomers from a DDSQ prepared with nadic anhydride (ND) through hydrosilylation (to form DDSQ-ND) and then its reactions with p-aminophenol and o-aminophenol to form DDSQ-ND-p-OH and DDSQ-ND-o-OH, respectively. Four different DDSQ-functionalized BZ monomers were prepared through reacting DDSQ-ND-p-OH and DDSQ-ND-o-OH with CH2O and either aniline or allylamine: pBDDSQ-AN, pBDDSQ-AL, oBDDSQ-AN, and oBDDSQ-AL. All of these polybenzoxazine (PBZ)/DDSQ hybrids exhibited high thermal stability and high char yields after thermal curing, based on thermogravimetric analysis (TGA), because the DDSQ inorganic nanoparticles were dispersed homogeneously in the PBZ matrices, as evidenced using electron microscopy. For example, the thermal decomposition temperature (T d) and char yield of pBDDSQ-AN after thermal curing at 270 °C were 521 °C and 75 wt %, respectively. More interestingly, the char yield of the ortho-substituted oBDDSQ-AN increased from 72.7 wt % prior to thermal treatment to 76.0 wt % after thermal treatment at 450 °C, indicating that the polybenzoxazole may have formed after such thermal treatment to increase the char yield, which was higher than that of the para-substituted pBDDSQ-AN.

Low melting point, high thermal stable branched benzoxazines resin derived from mixed-substituted phosphazene core

“…1,3-Benzoxazine, a monomer of newly developed thermosetting resins called polybenzoxazines (PBZ), can be synthesized conveniently from primary amine, formaldehyde, and phenol by one-pot Mannich condensation [1,2]. Due to the wide range of selectivity of raw materials, it provides benzoxazines with molecular design flexibility and can meet the practical requirement by designing different monomer structures [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. For example, the tetra-functional fluorene-based benzoxazine resin (t-BF-a-c) was synthesized, which exhibits an exothermal peak at 276°C, and displays good processability and wide process window(60°C) due to the incorporation of cardanol [21].…”

Main Chain–Type Block Copolymers through Atom Transfer Radical Polymerization from Double-Decker–Shaped Polyhedral Oligomeric Silsesquioxane Hybrids

“…Phenyltrimethoxysilane [Scheme 1a], methyl dichlorosilane, tetrahydrofuran (THF), 2-propanol, charcoal, sodium hydroxide (NaOH), ethanol (EtOH), methanol (MeOH), sodium bicarbonate (NaHCO3), acetonitrile, cyclohexane, and magnesium sulfate (MgSO4) were also purchased from Aldrich. DDSQ was synthesized as described previously [Scheme 1c] [45][46][47].…”

Progress in the Synthesis of Bifunctionalized Polyhedral Oligomeric Silsesquioxane

“…When 4,4-oxydianiline is replaced by p-aminophenol or o-aminophenol, hydroxyl group modified B-POSS can be formed, as reported by Chen et al (Figure 4). [73] First, compound 5 was reacted with p-aminophenol or o-aminophenol to form the para-aminophenol anhydride B-POSS (B-POSS-ND-p-OH) (6) and ortho-aminophenol anhydride B-POSS (B-POSS-ND-o-OH) (7), as shown in Figure 4. The influence of the substitution position of the B-POSS on the thermal stability and thermal behavior of these (benzoxazine) (BZ) monomers was well investigated.…”