Curing octaepoxysilsesquioxane with different curing agents

Abstract

Octaepoxysilsesquioxane (POSS‐Ep) was first synthesized by the hydrolysis and condensation of γ‐[(2,3)‐epoxypropoxy]propyltrimethoxysilicane (KH‐560) with the presence of ethanol and HCl at 55°C for 72 h. Then, it was cured with 4,4′‐diaminodiphenylsulfone (DDS) and methylnadic anhydride (MNA), respectively. The curing reactions between POSS‐Ep and DDS or MNA were investigated by FTIR. Thermal stability of the cured nanocomposites was studied by TGA. The micromophologies of the obtained hybrids were observed by SEM. FTIR results show that POSS‐Ep can be cured completely with DDS or MNA to obtain the final organic–inorganic (O–I) hybrids after the same experimental curing cycle: 120°C/2 h + 140°C/2 h + 160°C/2 h + 180°C/2 h + 200°C/2 h. TGA results show that POSS‐Ep/DDS hybrid displays better thermal stability than that of POSS‐Ep/MNA hybrid. Initial thermal degradation temperature (Tdi) of POSS‐Ep/DDS hybrid is 420°C, 195°C higher than that of POSS‐Ep/MNA (225°C). SEM images of the fracture surfaces of the hybrids suggest the cured POSS‐Ep possesses good mechanical properties. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Epoxy-functionalized polyhedral oligomeric silsesquioxane/cyanate ester resin organic-inorganic hybrids with enhanced mechanical and thermal properties

“…Bisphenol A dicyanate (2,2′‐bis(4‐cyanatophenyl)isopropylidene) (BADCy) with purity > 99.5 wt%, white granular crystal, was purchased from Shanghai Huifeng Kemao Ltd (Shanghai, China). Octaepoxysilsesquioxane was synthesized in our laboratory using the procedure described in the literature . γ‐[(2,3)‐epoxypropoxy]‐ propyltrimethoxysilane (KH‐560) was hydrolyzed and condensed at 55 °C for 72 h to synthesize POSS‐Ep.…”

“…Our group synthesized several kinds of POSS monomers and incorporated them into epoxy . Recently, we reported the synthesis and curing of an epoxy‐functionalized POSS monomer octaepoxysilsesquioxane (POSS‐Ep) . Considering that POSS‐Ep possesses not only good compatibility but also reactivity with many thermosetting polymers, POSS‐Ep/CE hybrids are expected to have excellent mechanical, dielectric and thermal properties.…”

Multifunctional POSS Cyclic Carbonates and Non-Isocyanate Polyhydroxyurethane Hybrid Materials

“…In general, POSS is readily prepared by the controlled hydrolysis of R 1 Si­(OR 2 ) 3 compounds, in which R 1 is alkyl with functional end groups and R 2 is methyl or ethyl. Typically, the direct hydrolysis of R 1 Si­(OR 2 ) 3 yields complex reaction mixtures containing different cage structures together with only partially condensed polysilsesquioxane cages. − In the preferred two-step process the hydrolysis of either HSi­(OR 2 ) 3 or HSiCl 3 yields Si–H functional POSS, which is purified and alkylated with olefins through hydrosilylation in the presence of the Speier or Karstedt Pt catalysts. − As molecular nanocomposites, POSS compounds combine the facile processing typical for thermosets with property profiles characteristic for ceramics such as high hardness, stiffness, abrasion resistance, thermal and oxidative stability, and inherent flame retardancy. ,, In conventional polyurethane (PU) synthesis, multifunctional epoxy-functionalized POSS molecules were employed as additives and improved tear resistance, Young’s modulus, and even thermal stability …”

Structure and property of tetrafluoroethylene‐propylene elastomer‐OVPOSS composites

“…[13][14][15][16] Several studies found reinforcements in the thermal stability 8,17,18 and mechanical properties 19,20 of composite materials. However, the effects of POSS fillers on material properties depend substantially on the interactions between POSS and the polymer matrix.…”

“…Polyhedral oligomeric silsesquioxanes (POSS), with the general formula (RSiO3/2)n (n ¼ 6,8,10…14), [5][6][7] is a nanometer-sized hybrid material that provides a better choice for preparing nanocomposites through copolymerization, 8,9 grafting, [10][11][12] or blending. [13][14][15][16] Several studies found reinforcements in the thermal stability 8,17,18 and mechanical properties 19,20 of composite materials.…”