Synthesis of epoxy resin–silica nanocomposites provided from perhydropolysilazane as a curing reagent and the precursor of silica domain

Abstract

Epoxy resin-silica nanocomposites with spherical silica domains with 29.0 nm in diameter in an epoxy resin matrix were synthesized from Bisphenol-A type epoxide monomer, 2,2-bis(4-glycidyloxyphenyl)propane (DGEBA), and perhydropolysilazane (PHPS, A[Si 2 ANH] n A). The volume fraction of silica domain in the composite varied from 5.4 to 37.8 vol % by varying the feed ratio of PHPS to the epoxide monomer. The reaction mechanism of epoxy group and PHPS was investigated by using glycidyl methacrylate as a model compound of the epoxy monomer by 1 H-nucular magnetic resonance and Fourier transform infrared spectrometry. Ammonia gas provided by the decomposition of PHPS with moisture converted PHPS to silica and cured the epoxy monomer. The curing of epoxy monomer preferably proceeded than the conversion of silica. The addition of 1,4-diaminobutane drastically accelerated the rate of curing; white and hard epoxy resin-silica nanocomposites were obtained. The good thermal stability of the composite prepared with DGEBA/PHPS/1,4-diaminobutane was observed by thermogravimetric analysis.

Oligosilylarylnitrile: The Thermoresistant Thermosetting Resin with High Comprehensive Properties

“…After thermal cure into a three-dimensional cross-linking network, the inert groups still displayed their absorption peaks (aromatic C–H at 3050 cm –1 , aliphatic C–H at 2900 cm –1 , and Si–C at 1270 cm –1 ), whereas the curable groups disappeared (nitrile CN at 2250 cm –1 and Si–H at 2140 cm –1 ). The new broad peak at 3300 cm –1 was owing to the oxidation/hydrolysis of Si–H by oxygen or moisture during elevated curing temperature under air condition. , The molecular structure was confirmed by the comparison of IR spectra of the parent and cured resins.…”

“…The new broad peak at 3300 cm −1 was owing to the oxidation/hydrolysis of Si−H by oxygen or moisture during elevated curing temperature under air condition. 22,23 The molecular structure was confirmed by the comparison of IR spectra of the parent and cured resins.…”

Monitoring the curing processes of epoxy oligomers with partially substituted polyethoxymetallosiloxanes by IR spectroscopy and thermomechanical analysis

“…The addition of an organosilicon component during the formation of an epoxy material can improve its thermo‐mechanical properties. Nearly all classes of organosilicon compounds can be used, both as fragments embedded into the epoxy matrix (in particular, as hardeners 14 ) and as fillers or filler modifiers for an intended material 15–18 . The most common studies in the literature deal with the incorporation of silsesquioxane moieties into an epoxy material, most often in the form of polyhedral organosilsesquioxanes (POSS) 19,20 .…”

“…The thermomechanical properties of an epoxy material may also be improved by incorporating silica (SiO 2 ) 27,28 or its precursors 14,29 at the curing stage, which results in a nanocomposite material. However, in this case, the curing rate decreases, and problems of compatibility of the precursor with the epoxy matrix 29 and uniform distribution of the nanofiller in the material bulk often appear 30 .…”

Microstructure and phase evolution of polymer‐derived SiHfOC ceramic microspheres

“…The synthesis of the Hf-PSN microspheres proceeds in two steps. First of all, when the PSN precursor is exposed to water in the hydrothermal process, the hydrolysis of the Si-N bonds occurs in the precursor, in which at the same time gaseous products are released, such as NH 3 , followed by the formation of Si-OH groups as intermediates [51][52][53][54]. Further condensation and cross-linking reactions of the precursor may lead to the formation of Si-O-Si and Si-O-C bonds in the PSN microspheres, in accordance with the FT-IR results in Figure5(Reaction 1).…”