Characterization and Curing Kinetics of Epoxy/Silica Nano-Hybrids

Abstract

The sol-gel technique was used to prepare epoxy/silica nano-hybrids. The thermal characteristics, curing kinetics and structure of epoxy/silica nano-hybrids were studied using differential scanning calorimetry (DSC), 29Si nuclear magnetic resonance (NMR) and transmission electron microscopy (TEM). To improve the compatibility between the organic and inorganic phases, a coupling agent was used to modify the diglycidyl ether of bisphenol A (DGEBA) epoxy. The sol-gel technique enables the silica to be successfully incorporated into the network of the hybrids, increasing the thermal stability and improving the mechanical properties of the prepared epoxy/silica nano-hybrids. An autocatalytic mechanism of the epoxy/SiO2 nanocomposites was observed. The low reaction rate of epoxy in the nanocomposites is caused by the steric hindrance in the network of hybrids that arises from the consuming of epoxide group in the network of hybrids by the silica. In the nanocomposites, the nano-scale silica particles had an average size of approximately 35 nm, and the particles were well dispersed in the epoxy matrix, according to the TEM images.

Synthesis and Properties of Carbon Nanotube-Grafted Silica Nanoarchitecture-Reinforced Poly(Lactic Acid)

“…As noted, MWCNT-grafted silica nanohybrids were synthesized by the generation of silica nanoparticles on the surface of MWCNTs using the sol-gel technique. Specifically, siloxane alkoxide underwent various hydrolysis and polycondensation reactions, which formed a network of siloxane bonds in the MWCNT-grafted silica nanohybrids [ 20 ]. When the nanohybrids were in a solid-state, 29 Si NMR spectra of the network of siloxane bonds showed three signals at −92, −101, and −111 ppm, which were assigned to (HO) 2 Si(SiO) 2 (Q 2 ), HOSi(SiO) 3 (Q 3 ), and SiO 4 (Q 4 ), respectively [ 20 , 26 , 32 , 33 ].…”

“…Polymerization is associated with the formation of a one-, two-, or three-dimensional network of metal-oxide (M–O–M) bonds and is accompanied by the production of H–O–H and R–O–H species [ 20 , 21 , 22 ]. The influence of synthetic conditions, such as the applied metal alkoxide concentration, pH, temperature, catalyst morphology, and inorganic metal oxide structure, has been thoroughly studied in recent decades [ 20 , 21 , 22 , 23 , 24 , 25 , 26 ]. In our own earlier research [ 7 ], we examined tetraisopropyl titanate (TIPT), a metal alkoxide that underwent various hydrolysis and polycondensation reactions and formed a network of titanium oxide bonds.…”

Reactive particles from in situ silane‐polycondensation‐induced self‐assembly of poly(styrene‐alt‐maleic anhydride) as toughener for epoxy resins

“…The variation curve of E a with conversion rate is shown in Figure . It is demonstrated that the curing process of epoxy in this study follows a typical autocatalytic mechanism . As shown, the shape of the E a curve for the E51/MHHPA system does not change substantially after adding 5 wt % of SMA‐APTES particles, despite the E a of the modified case is a little lower than that of the neat one at early stage of curing (<40%).…”

Mechanical and Thermal Stability of Epoxy – TEOS Hybrids Materi-als using Sol-Gel Method

“…In general, organic and inorganic structures are covalently bonded, more or less strongly [1]. Epoxy composites, which are hybrid organic-inorganic materials, have a wide range of engineering applications that require a high strength to weight ratio, low cost and ease of fabrication [2].this reduces the stable lifetime of these materials. Experiment the water diffuse in epoxy in two states, evenly distributed water molecules between the polymer chain and condensed water in fractures and cavities [3].An epoxy is a copolymer formed from two different chemicals referred as the resin and the hardener.…”

“…A hybrid organic/inorganic has been thought of in order to achieve a homogeneous combination of both materials or somehow control their properties [6]. Sol-gel method products many shape different have various applications, such as thin films, protective coating, decorative coating, electro-optic components, composite, and hybrid materials [7,8]. Mustafa et al [9] studied the effect water absorption on wear test with epoxy / silica of solgel method and show the water absorption was found to be highly effective on the wear behavior of hybrids.…”