A facile synthesis of cyanate ester silica hybrid nanocomposites by in situ sol-gel method

Abstract

High performance cyanate ester—silica hybrid nanocomposites were prepared using the sol—gel method through in situ reaction. The methodology adopted here was the formation of a covalent bond between the bisphenol-A cyanate ester (CE) and silica matrix utilizing γ-aminopropyltriethoxysilane (γ-APS) as coupling agent. The covalent bond formation in the hybrid was confirmed by Fourier transform infrared analysis and solvent extraction. Thermal and morphological properties of the hybrid materials were investigated by differential scanning calorimetry, thermogravimetric analysis and scanning electron microscopy. The CE—silica hybrids show improved thermal properties. The double degradation curves observed from thermogravimetric analysis may be due to the weak adduct linkage and the cleavage of the triazine ring in the hybrid. The nitrogen porosimetry study confirmed the molecular level dispersion of cyanate ester in the cyanate ester—silica hybrid nanocomposites.

Low surface free energy cyanate ester–silica hybrid (CE–SiO2) nanomaterials for low k dielectric applications

“…9 The sol-gel technique is a convenient method for the synthesis of nanocomposite materials consisting of organic and inorganic compounds. [10][11][12][13][14][15][16][17][18][19][20][21] By application of the sol-gel process, organic-inorganic hybrid materials can be generated using different synthetic techniques with various inorganic and organic starting compounds. The mild condi-tions required for the sol-gel process make it attractive for application in the synthesis of organic-inorganic hybrid nanomaterials; it involves the hydrolysis of metal alkoxides to produce metal hydroxides, followed by condensation of the hydroxyl groups to form inorganic networks.…”

“…When inorganic networks are mixed with polymer solutions or with monomers during polymerization, organic-inorganic hybrid nanocomposites can be obtained. 17,18 In general, physical associations like H-bonding or p-p interactions are used to prepare organic-inorganic hybrids in this approach. However coupling agents are frequently utilized to introduce covalent bonds between the organic and inorganic phases.…”

“…Although coupling agents may perform several useful functions at the interface in composite systems, they are expected to improve the adhesion between the organic and inorganic components, and improve the retention of properties under a variety of circumstances. 17,18,[22][23][24] A number of thermoplastics have been utilized for the preparation of organic-inorganic nanocomposites by the solgel process, such as PS-SiO 2 , 25,26 polyimide-SiO 2 , [27][28][29] PMMA-SiO 2 , 30,31 polyimide-TiO 2 , 32,33 etc. Only a few researchers have studied thermosetting systems, and they have focused primarily on cyanate ester (CE) resins, which are currently in widespread use for a variety of applications from structural aerospace composites to electronic insulation.…”

Silicon-containing trifunctional and tetrafunctional cyanate esters: Synthesis, cure kinetics, and network properties

“…A strategy used to provide thermooxidative protection in cyanurate polymer networks that has been explored through much recent investigation is the incorporation of silicon or siloxy moieties in the form of monomers and cocuratives, blends and modifiers, silica nanoparticles, clay nanoplatelets, or other silicon‐containing nanostructures including oligomeric silsesquioxanes . While the addition of silicon in fully oxidized form (i.e., as SiO 2 ) can provide an in‐place barrier to oxygen permeation, the use of unoxidized organosilicon moieties or partly oxidized silicates allows for the in situ generation of a protective barrier during high‐temperature oxidation or exposure to energetic forms of oxygen (such as atomic oxygen in low Earth orbit) .…”

Development of coating formulation with silica–titania core–shell nanoparticles against pathogenic fungus

“…Nano-silica has been proved to be a very promising material due to its low density, good thermal and mechanical stability, and chemical inertia in many fields of applications like catalysis, drug delivery, chemical sensors, chromatography, micro-reactor and biological images [18]. Coating of titania onto silica can enhance its stability and UV absorption property because individual TiO 2 nanoparticles with high surface area are thermally unstable and lose their surface area readily [19]. This core–shell formation improves the antimicrobial property of the coatings as well as strength of the coated surface.…”