Preparation and anticorrosive properties of hybrid coatings based on epoxy‐silica hybrid materials

A series of sol‐gel derived organic–inorganic hybrid coatings consisting of organic epoxy resin and inorganic silica were successfully synthesized through sol‐gel approach by using 3‐glycidoxypropyl‐trimethoxysilane as coupling agent. Transparent organic–inorganic hybrid sol‐gel coatings with different contents of silica were always achieved. The hybrid sol‐gel coatings with low silica loading on cold‐rolled steel coupons were found much superior improvement in anticorrosion efficiently. The as‐synthesized hybrid sol‐gel materials were characterized by Fourier‐transformation infrared spectroscopy, ²⁹Si‐nuclear magnetic resonance spectroscopy and transmission electron microscopy. Effects of the material composition of epoxy resins along with hybrid materials on the thermal stability, Viscoelasticity properties and surface morphology were also studied, respectively. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Viscoelasticity of epoxy resin/silica hybrid materials with an acid anhydride curing agent

The viscoelasticity of epoxy resin/silica hybrid materials manufactured by the sol–gel process with an acid anhydride curing agent was investigated in terms of morphology. Transmission microscopy observations demonstrated that all the prepared hybrid samples had a two‐phased structure consisting of an epoxy phase and a silica phase. The formed silica had either nanosized particles or coarse domains, depending on the catalyst for the sol–gel process. Raman spectroscopy analysis showed that the formed silica had features typical of sol–gel derived silica glass and that the ring‐opening reactions of the epoxy groups developed in the hybrid samples and in the neat epoxy samples. In dynamic mechanical thermal analysis, there were two transition temperatures due to epoxy chain mobility and epoxy network relaxation, through which the moduli changed by nearly 3 orders of magnitude. The hybridization disturbed epoxy network formation but also reinforced the epoxy network with the formed silica, which was characterized by the activation energy of the network relaxation; therefore, the modulus of the rubbery state was correlated to the activation energy. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Thermally and mechanically enhanced epoxy resin‐silica hybrid materials containing primary amine‐modified silica nanoparticles

In this article, a series of hybrid materials consisted of epoxy resin matrix and well‐dispersed amino‐modified silica (denoted by AMS) nanoparticles were successfully prepared. First of all, the AMS nanoparticles were synthesized by performing the conventional acid‐catalyzed sol–gel reactions of tetraethyl orthosilicate (TEOS), which acts as acceded sol–gel precursor in the presence of 3‐aminopropyl trimethoxysilane (APTES), a silane coupling agent molecules. The as‐prepared AMS nanoparticles were then characterized by FTIR, ¹³C‐NMR, and ²⁹Si‐NMR spectroscopy. Subsequently, a series of hybrid materials were prepared by performing in situ thermal ring‐opening polymerization reactions of epoxy resin in the presence of as‐prepared AMS nanoparticles and raw silica (RS) particles (i.e., pristine silica). AMS nanoparticles were found to show better dispersion capability in the polymer matrices than that of RS particles based on the morphological observation of transmission electron microscopy (TEM) study. The better dispersion capability of AMS nanoparticles in hybrid materials was found to lead enhanced thermal, mechanical properties, reduced moisture absorption, and gas permeability based on the measurements of thermo gravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and gas permeability analysis (GPA), respectively. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Properties of hybrid materials derived from hydroxy‐containing linear polyester and silica through sol–gel process. I. Effect of thermal treatment

The transparent hybrid material, HLP/SiO₂, was prepared by an in situ sol–gel process of tetraethoxysilane (TEOS) at 30°C in the presence of hydroxy‐containing linear polyester (HLP) obtained by ring‐opening reaction of diglycidyl ether of bisphenol A (DGEBA) with adipic acid under the catalyzation of triphenylphosphine (TPP). The hetero‐associated hydrogen bonds between the HLP and the residual silanol of silica in the hybrids were investigated by FTIR spectroscopy. Upon heating the hybrid, the interfacial force between the HLP matrix and the silica network changed from hydrogen bonds into covalent Si—O—C bonds through dehydration of hydroxy groups in HLP with residual silanol groups in the silica network. The existence of covalent Si—O—C bonds was proved by solid‐state ²⁹Si‐NMR spectra. Other properties such as tensile strength, glass transition temperature (T_g ), solubility, and thermal stability of the hybrids before and after heat treatment were studied in detail. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 1179–1190, 2000     

Structure–property behavior of UV‐curable polyepoxy–acrylate hybrid materials prepared via sol–gel process

UV‐curable, hard, transparent organic/inorganic hybrid material with an improved mechanical property was prepared by the sol–gel process, based on a commonly used epoxy acrylate (EA) oligomeric resin. Systematic experiments were carried out to study the effect of the inorganic content, the acid content, and the content of a silane coupling agent on the property behavior of the hybrid materials. The structure of the hybrids were characterized by IR spectra and SEM observation. Results from thermogravimetric analysis (TGA) and mechanical measurement show that the properties of the hybrids differ with the changes of these variables. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1654–1659, 2003     

Effect of baking treatment and materials composition on the properties of bulky PMMA–silica hybrid sol–gel materials with low volume shrinkage

A series of bulky PMMA–silica hybrid sol–gel materials had been successfully prepared through the conventional HCl‐catalyzed sol–gel approach with 2‐hydroxyethyl methyl methacrylate (HEMA) as coupling agent under pumping pretreatment (i.e., exhaustive vacuum evacuation). In this work, the hydroxyl groups of HEMA monomers were first cohydrolyzed with various contents of tetraethyl orthosilicate (TEOS) to afford chemical bonding for the forming silica networks by removal of solvent and byproduct of sol–gel reactions through pumping pretreatment before gelation reactions. Subsequently, the resultant viscous solution was then copolymerized with methyl methacrylate (MMA) monomers at specific feeding ratios by using benzoyl peroxide (BPO) as free‐radical initiator. Eventually, transparent bulky organic–inorganic hybrid sol–gel materials loaded with different silica content were always achieved. The obtained bulky hybrid sol–gel materials were found to be transparent, crack‐free, and of relatively low volume shrinkages even in high silica content. The as‐prepared bulky hybrid sol–gel materials were then characterized through silicon element mapping studies of energy‐dispersive X‐ray (EDX) and transmission electron microscopy (TEM). Effect of heating process at 150°C for 5 h after polymerization and material composition on the thermal properties, mechanical strength, and optical clarity of a series of bulky PMMA–silica hybrid sol–gel materials was investigated and compared by thermogravimetric analysis (TGA), thermomechanical analysis (TMA), hardness test, dynamic mechanical analysis (DMA), and UV–vis transmission spectroscopy, respectively. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1151–1159, 2006     

Synthesis of poly(methylphenylsiloxane)/phenylene‐silica hybrid material with interpenetrating networks and its performance as thermal resistant coating

In this study, poly(methylphenylsiloxane) (PMPS) and phenylene‐silica based hybrid material with interpenetrating networks was prepared by a two‐step sol–gel process. Firstly, in the presence of H₂SO₄, the phenylene‐silica was formed as sol particles with high branching degree by cohydrolysis and condensation of phenylene‐bridged monomer, tetraethoxysilane (TEOS), and hexamethyldisiloxane (MM). Then, the intermediate transformed into gel framework in polymer matrix using alkali catalyst, in order to produce a homogenous hybrid material with interpenetrating networks. The structure of prepared hybrid material was characterized by FTIR and NMR, suggesting that phenylene‐silica framework was imported into polymer matrix and the hybrid products have a much higher network chain density than neat PMPS. The thermogravimetric analysis (TGA) shows that the prepared materials start to degrade at around 490°C. The results of tensile test indicate that the typical PMPS/phenylene‐silica hybrid material has a tensile strength up to 26 MPa and demonstrate a certain degree of flexibility. An increase of phenylene content in phenylene‐silica particles tends to produce hybrid materials with improved thermal stability and tensile strength. The hybrid coating films after calcinating at 350 and 400°C for 2 h exhibit a good mechanical performance on adhesion, impact strength and flexibility. Electrochemical impedance spectroscopy (EIS) measurements show that the investigated films have an extremely high electric resistance (10¹⁰ Ohm·cm²) and a satisfied impermeability to 3.5 wt % sodium chloride solution. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Synthesis and characterization of a hybrid material based on a trimethoxysilane functionalized benzoxazine

A polybenzoxazine/polysiloxane hybrid has been prepared by sol–gel process and ring‐opening polymerization. For this purpose, first a functionalized benzoxazine was synthesized from bisphenol A, paraformaldehyde and 3‐(trimethoxysilyl) propylamine, with initial molar ratio 1 : 4 : 2, and 95% yield. The structure of the monomer was characterized by Fourier transform infrared (FTIR) spectroscopy and nuclear magnetic resonance. The sol–gel process and curing behavior have been studied by FTIR spectroscopy and differential scanning calorimetry. The dynamic mechanical thermal analysis of the hybrid material (Bz‐PSi) showed higher T_g and storage modulus respect to the conventional polybenzoxazine (Bz‐BA). Also, the thermogravimetric analysis revealed a better thermal stability. The high limiting oxygen index (LOI) values (about LOI = 32) confirmed similar effective flame retardance properties of the hybrid material respect to conventional benzoxazine. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

New epoxy/silica‐titania hybrid materials prepared by the sol–gel process

A new type of inorganic‐polymer hybrid materials of epoxy/silica‐titania had been prepared by incorporating grafted epoxy, which had been synthesized by epoxy and tetraethoxysilane (TEOS), with highly reactive TEOS and tetrabutyltitanate (TBT) by using the in situ sol–gel process. The grafted epoxy was confirmed by Fourier transform infrared spectroscopy (FT‐IR) and ¹H‐NMR spectroscopic technique. Results of FT‐IR spectroscopy and atomic force microscopy (AFM) demonstrated that epoxy chains have been covalently bonded to the surface of the SiO₂‐TiO₂ particles. The particles size of SiO₂‐TiO₂ are about 20–50 nm, as characterized by AFM. The experimental results showed that the glass‐transition temperatures and the modulus of the modified systems were higher than that of the unmodified system, and the impact strength was enhanced by two to three times compared with that of the neat epoxy. The morphological structure of impact fracture surface and the surface of the hybrid materials were observed by scanning electron microscopy and AFM, respectively. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1075–1081, 2006     

Organic‐acid‐catalyzed sol–gel route for preparing poly(methyl methacrylate)–silica hybrid materials

In this study, a series of organic–inorganic hybrid sol–gel materials consisting of a poly(methyl methacrylate) (PMMA) matrix and dispersed silica (SiO₂) particles were successfully prepared through an organic‐acid‐catalyzed sol–gel route with N‐methyl‐2‐pyrrolidone as the mixing solvent. The as‐synthesized PMMA–SiO₂ nanocomposites were subsequently characterized with Fourier transform infrared spectroscopy and transmission electron microscopy. The solid phase of organic camphor sulfonic acid was employed to catalyze the hydrolysis and condensation (i.e., sol–gel reactions) of tetraethyl orthosilicate in the PMMA matrix. The formation of the hybrid membranes was beneficial for the physical properties at low SiO₂ loadings, especially for enhanced mechanical strength and gas barrier properties, in comparison with the neat PMMA. The effects of material composition on the thermal stability, thermal conductivity, mechanical strength, molecular permeability, optical clarity, and surface morphology of the as‐prepared hybrid PMMA–SiO₂ nanocomposites in the form of membranes were investigated with thermogravimetric analysis, differential scanning calorimetry, dynamic mechanical analysis, gas permeability analysis, ultraviolet–visible transmission spectroscopy, and atomic force microscopy, respectively. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Electrochemical investigations on the corrosion protection effect of poly(vinyl carbazole)‐silica hybrid sol–gel materials

A series of sol–gel derived organic–inorganic hybrid coatings consisting of organic poly (vinyl carbazole) (PVK) and inorganic silica (SiO₂), with 3‐(trimethoxysilyl)propyl methacrylate (MSMA) as coupling agent, were successfully synthesized. First of all, vinyl carbazole (VCz) monomers are copolymerized with MSMA by performing free‐radical polymerization reactions with AIBN as initiator. Subsequently, as‐prepared copolymer (i.e., sol–gel precursor) was further reacted with various feeding content of tetraethyl orthosilicate (TEOS) through organic acid (CSA)‐catalyzed sol–gel reaction to form a series of PVK‐silica hybrid (PSH) sol–gel materials. The as‐synthesized hybrid materials were subsequently characterized by Fourier‐Transformation infrared (FTIR) spectroscopy and solid‐state ²⁹Si NMR. It should be noted that the PVK‐SiO₂ hybrid (PSH) coating on cold‐rolled steel (CRS) electrode with low silica loading (e.g., 10 phr) was found to be superior in anticorrosion property over those of neat PVK based on a series of electrochemical measurements such as corrosion potential, polarization resistance, corrosion current, and electrochemical impedance spectroscopy in 3.5 wt% NaCl electrolyte. The better anticorrosion performance of PSH coatings as compared to that of neat polymer may probably be attributed to the stronger adhesion strength of PSH coatings on CRS electrode, which was further evidenced by Scotch tape test evaluation. Increase of adhesion strength of PSH coatings on CRS electrode may be associated with the formation of Fe–O–Si covalent bonds at the interface of PSH coating and CRS electrode based on the FTIR–RAS (reflection absorption spectroscopy) studies. POLYM. COMPOS., 2012. © 2011 Society of Plastics Engineers     

Organic base‐catalyzed sol–gel route to prepare PMMA–silica hybrid materials

A series of sol–gel‐derived organic–inorganic hybrid materials that comprise organic poly(methyl methacrylate) (PMMA) and inorganic silica (SiO₂) was successfully prepared using aniline as an organic base catalyst to catalyze the sol–gel reactions of tetraethylorthosilicate (TEOS). Aniline was adopted not only as a catalyst but also as a dispersing agent during the preparation of the hybrid materials. The as‐prepared hybrid materials were then characterized using transmission electron microscopy, SEM/energy dispersive X‐ray spectroscopy and Fourier transform infrared spectroscopy. The characteristic temperatures (including T_d and T_g) of the hybrid materials slightly exceeded those of neat PMMA, as revealed from thermogravimetric analysis and differential scanning calorimetry evaluations. Studies of the protection against corrosion demonstrated that the hybrid coatings all improved the protection performance on cold‐rolled steel coupons relative to that of neat PMMA coatings, according to measurements of electrochemical corrosion parameters. Additionally, incorporating silica particles into the polymer may effectively reduce the gas permeability of the polymer membrane. Reducing the size of silica particles (at the same silica feeding) further improved the gas barrier property. Optical clarity studies indicated that introducing silica particles into the PMMA matrix may slightly reduce the optical clarity of the films/membranes, as determined by UV‐visible transmission spectroscopy. The contact angle of H₂O of the hybrid films increased with the amount of aniline. Copyright © 2006 Society of Chemical Industry Society of Chemical Industry     

Structure–property relationship in epoxy‐silica hybrid nanocomposites: The role of organic solvent in achieving silica domains

The thermo‐mechanical properties of a series of epoxy‐silica hybrid composites prepared through sol–gel process are evaluated in a manner that the effect of organic solvent on the formation of silica domains is highlighted. By means of infrared spectroscopy, small‐angle X‐ray scattering, scanning electron microscope, dynamic mechanical thermal analysis, and thermo‐gravimetric analyzer, the specimens were morphologically studied varying the type of organic solvent. Among polar and nonpolar solvents incorporated by the organic–inorganic hybrid system, a mixture of xylene and ethanol (3:1) was properly comparable with tetrahydrofuran (THF) solvent regarding appearance and thermo‐mechanical characteristics. Enhanced thermal stability and modulus was observed upon increasing solvent content. Also, a proper dispersion of silica domains throughout the epoxy was seen in the case that the xylene/ethanol mixture or THF served as solvent. It is to be emphasized that the assigned mixture is environmentally better than that of THF. J. VINYL ADDIT. TECHNOL., 21:305–313, 2015. © 2014 Society of Plastics Engineers     

High‐Tg,heat resistant epoxy–silica hybrids with a low content of silica generated by nonaqueous sol–gel process

The epoxy‐silica hybrids showing high T_g and thermal stability are prepared by the non‐aqueous sol–gel process initiated with borontriflouride monoethylamine. Tetramethoxysilane (TMOS) is used as a precursor of silica and 3‐glycidyloxypropyl trimethoxysilane as a coupling agent to strengthen the interphase interaction with an epoxy matrix. The basic factors governing the nonaqueous sol–gel process are studied in order to reveal the formation–structure–properties relationships and to optimize the hybrid composition as well as conditions of the nonaqueous synthesis. The formation of the hybrid, its structure, thermomechanical properties and thermal stability are followed by chemorheology experiments, NMR, DMA and TGA. The most efficient reinforcement of the epoxy network is achieved by the combination of both alkoxysilanes, showing synergy effects. The hybrids with a low content (～10 wt %) of the in situ generated silica exhibit dramatic increase in T_g and the high modulus, 335 MPa, up to the temperature 300°C. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40899.     

Study the factors affecting the performance of organic–inorganic hybrid coatings

In this article, a series of hybrid organic–inorganic coatings based on silica‐epoxy composite resins were prepared with the sol‐gel method by using γ‐aminopropyl triethoxysilane as a coupling agent. Especially, the research emphasized on the factors that influenced on the properties of the prepared hybrid coatings. Firstly, epoxy resin was reacted with γ‐aminopropyl triethoxysilane at a specific feeding molar ratio; subsequently, the asprepared sol–gel precursor was cohydrolyzed with tetraethoxysilane (TEOS) at various contents to afford chemical bondings to form silica networks and give a series of organic–inorganic hybrid coatings. They were loaded and cured on steel panels and characterized for FTIR, TGA, DSC, water contact angles (WCA), pencil hardness, surface & three‐dimensional morphological studies, and potentiodynamic polarization tests. The surfaces of the hybrid coatings showed Sea‐Island or Inverting Sea‐Island morphologies at a certain relative content of two components, which made the coatings possess hydrophobic property. Due to the contribution of organic and inorganic components, the prepared hybrid coatings possess a lot of properties such as pencil hardness, thermotolerance, and corrosion resistance. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41010.     

Greener Chemistry for Hybrid Materials,Alcohol‐Free Synthesis with an Epoxy‐Cyclohexyl Precursor

Green synthesis is one of the hot topics in the chemistry of hybrid organic–inorganic materials. A alcohol‐free sol–gel process has been developed to prepare optically transparent hybrid films from an epoxy bearing alkoxide, [2‐(3,4‐epoxy‐cyclohexyl)‐ethyl]‐trimethoxysilane (ECTMS). The synthesis is simple and effective because only two components, ECTMS and an aqueous solution of NaOH, are employed. Infrared spectroscopy has been used to monitor the reactivity of the precursor sol as a function of the aging time. Organic–inorganic hybrid films have been then prepared with the different sols via spin‐coating. The presence of the cyclohexyl ring slows down dramatically both the epoxide opening and the capability of the resulting diols in forming a tricyclic dioxane derivative. The highly basic conditions employed in the synthesis favor the formation of the cyclohexyl rings and cage‐ and ladder‐like silica structures. The hybrid films have shown a high transmittance in the visible range and a thermal stability up to 200 °C.

     

SiO2 reinforced HDPE hybrid materials obtained by the sol–gel method

Novel high density polyethylene (HDPE)/SiO₂ hybrid materials were prepared by the sol–gel process using tetraethoxysilane (TEOS). HDPE and synthesized HDPE‐g‐vinyl trimethoxysilane (VTMS) through melt grafting method was used as the raw material. The structure and thermal, mechanical properties of hybrid materials were investigated by Fourier transform infrared (FTIR) spectroscopy, X‐ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), simultaneous thermogravimetric (TG), differential thermal analysis (DTA), and tensile tests, respectively. Silica phase in the HDPE‐g‐VTMS hybrids showed a network structure and nano‐scale size. The covalent bonds between organic and inorganic phases were introduced by the HDPE‐g‐VTMS bearing trimethoxysilyl groups, which underwent hydrolytic polycondensation with TEOS. The thermal stability and mechanical properties of HDPE‐g‐VTMS hybrids were obviously improved by embedded silica networks. It was found that the silica content in the HDPE‐g‐VTMS hybrid material was linearly increased with the TEOS dosage. The formation of the HDPE‐g‐VTMS hybrid was beneficial for enhanced mechanical strength and thermal stability, in comparison with the neat HDPE. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2014 , 131, 39891.     

Preparation of epoxy resin/silica hybrid composites for epoxy molding compounds

Phenolic novolac/silica and cresol novolac epoxy/silica hybrids were prepared through in situ sol‐gel reaction of tetraethoxysilane (TEOS). The formed hybrids were utilized as a curing agent and an epoxy resin in epoxy curing compositions, respectively. Via the two‐step preparation route, the resulting epoxy resin/silica hybrid nanocomposites exhibited good thermal stability, high glass transition temperatures, and low coefficients of thermal expansion. High condensation degree of the condensed silica was observed with a high content of siloxane bridges, p > 85%, measured by ²⁹Si NMR. The two‐step route also provides feasibility of preparation of epoxy resin/silica hybrid nanocomposites compatible with the current processes of manufacturing of epoxy molding compounds. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 4047–4053, 2003     

Synthesis,spectral, and thermal characterization of photoreactive epoxy resin containing cycloalkanone moiety in the main chain

Dual functional epoxy resins were synthesized by solution polycondensation of 2,6‐bis(4‐hydroxy‐3‐methoxy benzylidene)cyclohexanone and 2,5‐bis(4‐hydroxy‐3‐methoxy benzylidene)cyclopentanone with epichlorohydrin. The synthesized epoxy resins were characterized systematically for their structure by UV, Fourier transform infrared (FTIR), ¹H NMR, and ¹³C NMR spectroscopic techniques. Thermal characterization of synthesized epoxy resins was carried out by thermogravimetric analysis, and differential scanning calorimetry (DSC) under nitrogen atmosphere. The self extinguishing property of synthesized oligomers was studied by determining limiting oxygen index (LOI) values using Van Krevelen's equation. X‐ray analysis showed that the epoxy resins containing cyclopentanone have higher degree of crystallinity. The photoreactive property of the synthesized epoxy resins in solution and film states was investigated by UV–Vis spectroscopy. The photocross‐linking proceeds through the dimerization of olefinic chromophore present in the main chain of the oligomer via 2π + 2π cycloaddition reaction. The influence of photoacid generator on the rate of photocross‐linking of epoxy resin was studied by FTIR. UV irradiation of the epoxy resin in presence of photoacid generator produces aromatic sulfonium cation radicals and aromatic radicals which initiate the cationic ring‐opening polymerization of oxirane ring. The photoreactivity studies of the oligomers by FTIR and DSC indicated the presence of dual functionality in the synthesized epoxy resins. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Environmental aging of cold‐cured epoxy‐silica hybrids prepared by sol−gel process

The article investigates the effects of long term environmental aging on thermal and mechanical properties of epoxy‐silica hybrids. These nanostructured materials, prepared by non‐aqueous sol‐gel process and in situ generation of nanosilica during epoxy curing at room temperature, present the potential to be used as cold‐cured adhesives for civil engineering and Cultural Heritage applications. A specifically developed conditioning procedure for these cold‐cured nanostructured materials was applied before moisture/water absorption tests. The work evidenced the superior durability of the studied epoxy‐silica hybrid, which kept its performances in severe, but realistic, environmental conditions with respect to traditional epoxy adhesives. The reduction in the glass transition temperature and mechanical properties of the studied epoxy‐silica hybrid, observed in the first weeks of environmental aging, was followed by a significant recovery. This was attributed to two concomitant phenomena: the reactivation of the incomplete curing reactions in the epoxy domains and the continuation of the condensation reactions in the siloxane domains activated by the absorbed water. Finally, the Fickian behavior, presented by the studied epoxy‐silica hybrid, was used as an indirect indication of the homogeneity of achieved microstructure, with well dispersed silica nanostructures in the epoxy network. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40093.