Curing kinetics, thermal, mechanical, and dielectric properties based on o‐cresol formaldehyde epoxy resin with polyhedral oligomeric (N‐aminoethyl‐γ‐amino propyl)silsesquioxane

Abstract

The curing reaction and kinetics of o‐cresol formaldehyde epoxy resin (o‐CFER) with polyhedral oligomeric silsesquioxane of N‐aminoethyl‐γ‐amino propyl group (AEAP‐POSS) were investigated by differential scanning calorimetry (DSC). The thermal, mechanical, and dielectric properties of o‐CFER/AEAP‐POSS nanocomposites were investigated with thermogravimetric analysis (TGA), torsional braid analysis (TBA), tensile tester, impact tester, and electric analyzer, respectively. The results show that the activation energy (E) of curing reaction is 58.08 kJ/mol, and the curing reaction well followed the Šesták‐Berggren (S‐B) autocatalytic model. The glass transition temperature (Tg) increases with the increase in AEAP‐POSS content, and reaches the maximum, 107°C, when the molar ratio (Ns) of amino group to epoxy group is 0.5. The nanocomposites containing a higher percentage of AEAP‐POSS exhibited a higher thermostability. The AEAP‐POSS can effectively increase the mechanical properties of epoxy resin, and the tensile and impact strengths are 2.84 MPa and 143.25 kJ m−2, respectively, when Ns is 0.5. The dielectric constant (ε), dielectric loss factor (tan δ), volume resistivity (ρv), and surface resistivity (ρs) are 4.98, 3.11 × 10−4, 3.17 × 1012 Ω cm3, and 1.41 × 1012 Ω cm2, respectively, similarly at Ns 0.5. Copyright © 2009 John Wiley & Sons, Ltd.

Disilyl Bis(Secondary Amine)-Enabled Epoxy Ring-Opening and Silylotropic N → O Migration Leading to Low Dielectric Epoxy Copolymers

“…Theoretically, the dielectricity is described by the Debye equation (eq ), where the parameters are number density of dipoles N , electric susceptibility α e , distortion polarization α d , orientation polarization related to the dipole moment μ, Boltzmann constant κ b , and the temperature T 4 . Specifically, for epoxy resins to have an improved low dielectricity, currently available strategies are through introducing low-polarizable groups and/or increasing the molecular free volume ratio. − …”

“…To reduce the dielectricity of a polymer, according to the Debye equation of dielectrics, , two strategies have been intensively explored: decreasing the polarizability and increasing the molecular free volume ratio. , In effect, both the strategies lead to dilution of the dipole density in the polymer. For epoxy resins, through introducing low-polarizable groups such as C–Si and C–F bonds to the host polymers, it is possible to lower ε to 3.0; nevertheless, the polar group generation in polymerization is not eliminated and the lowering of tanδ is usually not significant. − By incorporating micro-/nanoporous structures in the polymer matrix, the free volume ratio can be increased significantly, resulting in epoxy resins with ε down to 1.9. − The method of incorporating micro-/nanoporous structures, however, is hampered with the difficulty in precise control over the size and distribution of the pores as well as the mechanical properties of the polymers. The existing drawbacks in these strategies make it necessary to find more robust alternative methods for fabricating low dielectric epoxy resins.…”

Hybrid cationic ring-opening polymerization of epoxy resin/glycidyloxypropyl-polyhedral oligomeric silsesquioxane nanocomposites and dynamic mechanical properties

“…Choi J et al [22] have reported the organic/inorganic hybrid composites from the cubic silsesquioxane epoxy resins of octa(dimethylsiloxyethyl cyclohexylepoxide) silsesquioxane. We have reported the curing kinetics, thermal, mechanical, and dielectric properties for o-cresol formaldehyde epoxy resin with polyhedral oligomeric (N-aminoethyl-g-aminopropyl) silsesquioxane [23].…”