Preparation and properties of organosoluble polyimide/silica hybrid materials by sol–gel process

Organosoluble polyimide/silica hybrid materials were prepared using the sol–gel process. The organosoluble polyimide was based on pyromellitic anhydride (PMDA) and 4,4′‐diamino‐3,3′‐dimethyldiphenylmethane (MMDA). The silica particle size in the hybrid is increased from 100–200 nm for the hybrid containing 5 wt % silica to 1–2 µm for the hybrid containing 20 wt % silica. The strength and the toughness of the hybrids are improved simultaneously when the silica content is below 10 wt %. As the silica content is increased, the glass transition temperature (T_g) of the hybrids is increased slightly. The thermal stability of the hybrids is improved obviously and their coefficients of thermal expansion are reduced. The hybrids are soluble in strong polar aprotic organic solvents when the silica content is below 5 wt %. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 2977–2984, 1999     

Thermal,thermomechanical, and electrochemical characterization of the organic–inorganic hybrids poly(ethylene oxide) (PEO)–silica and PEO–silica–LiClO4

To study the effect of the silica content on the properties of the salt‐free and salt‐added hybrids based on poly(ethylene oxide) (PEO) and silica, two series of hybrids, PEO–silica and PEO–silica–LiClO₄ (O:Li, 9:1) hybrids were prepared via the in situ acid‐catalyzed sol–gel reactions of the precursors [i.e., PEO functionalized with triethoxysilane and tetraethyl orthosilicate (TEOS)]. The morphology of the hybrids was examined by scanning electron microscopy (SEM) of the fracture surfaces of the hybrid. The results indicated that the discontinuity develops with increasing the weight percent of silica in both hybrids. The differential scanning calorimetric (DSC) analysis indicated that effects of silica content on the glass transition temperatures (T_g) of the PEO phase were different in salt‐free and salt‐added hybrids. The T_g of PEO phase increased with increasing weight percent of silica in salt‐free hybrids, whereas the curve of T_g of PEO phase and silica content had a maximum at 35 wt % of silica content in salt‐added hybrids. For both salt‐free and salt‐added hybrids, peaks of the loss tangent, determined by dynamic mechanical analysis (DMA) were gradually broadened and lowered with increasing weight percent of silica. The storage modulus, E′, in the region above T_g increases with increasing silica content for both PEO–silica and PEO–silica–LiClO₄ hybrids. In the conductivity and composition curves for PEO–silica–LiClO₄ hybrids, the conductivity shows a maximum value of 3.7 × 10^?6 S/cm, corresponding to the sample with a 35 wt % of silica. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2471–2479, 2001     

Compatibilizing polyimide/silica hybrids by alkoxisilane‐terminated oligoimides: Morphology–Properties relationships

A fluorinated polyimide (PI), synthesized from 4,4′‐(hexafluoroisopropylidene) diphthalic anhydride and 4,4′‐diaminodiphenyl ether, was used as matrix for the preparation of PI/silica hybrids. The inorganic phase was obtained in situ by a sol–gel route with tetraethoxysilane as precursor. Both micron‐ and nano‐scale hybrids were obtained depending on the interfacial interaction between the organic and inorganic phases. To promote such interaction a compatibilizing agent was synthesized, in the form of an alkoxisilane‐terminated oligoimide. Both the PI and the coupling agent were characterized by FTIR and Raman spectroscopies and by GPC measurements. The effect of the coupling agent on the morphology of the hybrids and on the size of the silica particles was investigated by scanning electron microscopy. The viscoelastic, mechanical, and thermal properties of hybrid composites were studied. It was shown that by adding appropriate amounts of the compatibilizer it was possible to control the morphology and to obtain homogeneous nanostructured systems. A general improvement of the mechanical performances and of the thermal stability was demonstrated, together with an increase of T_g, which was found more pronounced for the nanocomposites than for the microcomposites. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Organic–inorganic hybrid materials. II. Chain mobility and stability of polysiloxaneimide–silica hybrids

Polysiloxaneimide–silica hybrid materials (PSI‐SiO₂) were obtained using the sol–gel technique by polycondensation of tetramethoxysilane (TMOS) in a polyamic acid solution. IR, ²⁹Si‐ and ¹³C‐NMR spectroscopy, and thermogravimetric analysis were used to study hybrids containing various proportions of TMOS and hydrolysis ratios. The morphology, dynamics, and thermal stability of the hybrids were investigated. The chain mobility of the hybrids was investigated by spin–spin relaxation time (T₂) measurements. The apparent activation energy (E_a) for degradation of the hybrids in air was studied by the van Krevelen method. The T₂ value was independent of the silica content whereas that of the E_a decreased as silica content increased. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 965–973, 2001     

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.     

Epoxy/silsesquioxane organic–inorganic hybrids: Sol–gel synthesis of inorganic precursors containing amino and phenyl groups

The synthesis of silsesquioxane oligomers containing amino and phenyl groups by sol–gel process and the formation of an organic–inorganic hybrid, by the reaction of amino groups of the silsesquioxane precursor with epoxy rings of diglycidyl ether of bisphenol A, have been investigated. Acid catalysis proved to be more efficient than basic catalysis for the condensation reaction between 3‐aminopropyltriethoxysilane (APES) and phenyltriethoxysilane (PETS) in ethanol. Liquid state ²⁹Si nuclear magnetic resonance (²⁹Si NMR) analysis indicated that T³ structures are the major phase forming the network structure. Infrared spectroscopy analyses confirmed the formation of the epoxy/silsesquioxane hybrid and showed that a high degree of cure was achieved. A distinct behavior of the glass transition temperature (T_g) between the hybrids cured at different time intervals after the chemical modification was observed, and the most significant value was an increase of 13°C in T_g obtained with the hybrid produced with silsesquioxane oligomers synthesized by sol–gel for 18 h. From thermogravimetric analyses (TGAs), it was observed an increase on the residual masses for the hybrids and a decrease in their degradation rates, suggesting an improvement of thermal stability. These results indicate the formation of a new organic–inorganic hybrid material with potential applications for high performance coatings and structural components. POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers     

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.     

Modification of polyethylene–octene elastomer by silica through a sol–gel process

In this study, tetraethoxysilane (TEOS) and a metallocene polyethylene–octene elastomer (POE) were chosen as the ceramic precursor and the continuous phase, respectively, for the preparation of new hybrids by an in situ sol–gel process. To obtain a better hybrid, a maleic anhydride‐grafted polyethylene–octene elastomer (POE‐g‐MAH), used as the continuous phase, was also investigated. Characterizations of POE‐g‐MAH/SiO₂ and POE/SiO₂ hybrids were performed by Fourier transform infrared (FTIR) and ²⁹Si solid‐state nuclear magnetic resonance (NMR) spectrometers, a differential scanning calorimeter (DSC), a thermogravimetry analyzer, and an Instron mechanical tester. The results showed that the POE‐g‐MAH/SiO₂ hybrid could improve the properties of the POE/SiO₂ hybrid because the interfacial force between the polymer matrix and the silica network was changed from hydrogen bonds into covalent Si? O? C bonds through dehydration of hydroxy groups in POE‐g‐MAH with residual silanol groups in the silica network. The existence of covalent Si? O? C bonds was proved by FTIR spectra. For the POE/SiO₂ and POE‐g‐MAH/SiO₂ hybrids, maximum values of the tensile strength and the glass transition temperature were found at 9 wt % SiO₂ since a limited content of silica might be linked with the polymer chains through the covalent bond. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 966–972, 2003     

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     

Study on morphology control and how to affect mechanical properties of polyimide/silica hybrid films

A series of polyimide (PI)/silica hybrid films were prepared by sol–gel method, using hydrolyzed tetraethoxysilane and poly amic acid‐imides (PAA‐Is), which were different imidization degree controlled by chemical imidization method. The imidization degree was characterized by Fourier transform infrared spectra and their corresponding morphology was characterized by scanning electron microscopy. The results show that there are two kinds of silica particles and their formative morphology obeys the double phase separation mechanism. According to the increase of PAA‐I imidization degree, amount of nano silica particles decreased and the diameter of macro silica particles increased in the hybrid films. Tensile testing, dynamic mechanical analysis, and thermal mechanical analysis results show that, according to the amount of nano silica particles increasing, the hybrids have the higher the mechanical properties, glass transition temperature (T_g), and thermal expansion coefficient. Through controlling PI/silica hybrid films microstructure, its mechanical properties can be controlled. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

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     

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     

Polyamide–silica nanocomposites: mechanical,morphological and thermomechanical investigations

BACKGROUND: The physical properties of polyamides can be enhanced through incorporation of inorganic micro‐ and nanofillers such as silica nanoparticles. Transparent sol‐gel‐derived organic‐inorganic nanocomposites were successfully prepared by in situ incorporation of a silica network into poly(trimethylhexamethylene terephthalamide) using diethylamine as catalyst. Thin films containing various proportions of inorganic network obtained by evaporating the solvent were characterized using mechanical, dynamic mechanical thermal and morphological analyses. RESULTS: Tensile measurements indicate that modulus as well as stress at yield and at break point improved while elongation at break and toughness decreased for the hybrid materials. The maximum value of stress at yield point (72 MPa) was observed with 10 wt% silica while the maximum stress at break point increased up to 66 MPa with 20 wt% silica relative to that of pure polyamide (44 MPa). Tensile modulus was found to increase up to 2.59 GPa with 10 wt% silica in the matrix. The glass transition temperature and the storage moduli increased with increasing silica content. The maximum increase in the T_g value (144 °C) was observed with 20 wt% silica. Scanning electron microscopy investigation gave the distribution of silica, with an average particle size ranging from 3 to 24 nm. CONCLUSION: These results demonstrate that nanocomposites with high mechanical strength can be prepared through a sol‐gel process. The increase in the T_g values suggests better cohesion between the two phases, and the morphological results describe a uniform dispersion of silica particles in the polymer matrix at the nanoscale. Copyright © 2007 Society of Chemical Industry     

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     

Synthesis,characterization, and thermo mechanical properties of siloxane‐modified epoxy‐based nano composite

In this study, polymer hybrid composites were synthesized by sol‐gel process. 3‐Amino‐propyltrimethoxysilane [APTMS)/γ‐Glycidoxypropyl trimethoxy‐silane (GPTMS); (4, 4′‐Methylene‐dianiline (DDM)] and 1,4‐Bis(trimethoxysilylethyl) benzene (BTB) were added to DGEBA type epoxy resin for anticipated to exhibit excellent thermal stability. Boron trifluoride monoethylamine (BF₃MEA) was used as catalyst. The structure of nanocomposites was characterized by attenuated total reflectance (ATR) and solid‐state ²⁹Si NMR which suggest EP‐APTMS‐BTB/EP‐GPTMS‐BTB possesses T³; T¹–T⁰, and T¹ structures when the BTB content was lower than 10 wt % and higher 20 wt %, respectively. BF₃MEA was proved to be an effective catalyst for the sol‐gel reaction of APTMS, but it could not promote for GPTMS. From TEM microphotographs, EP‐APTMS‐BTB (10 wt %) possesses a dense inorganic structure (particle size around 5–15 nm) compare with the loose inorganic structure of EP‐GPTM‐/BTB (10 wt %). DSC, TGA were use to analyze the thermal properties of the nanocomposites and DMA was used to analyze the dynamic mechanical properties of hybrid composites. The T_gs of all nanocomposites decreased with the increasing BTB content. A system with BTB content lower than 10 wt % showed good dynamic mechanical property and thermal stability (Td₅ increased from 336°C to 371°C, char yield increased from 27.4 to 30.2%). The structure of inorganic network affects the Td₅ and dynamic mechanical properties of composite. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40984.     

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.     

Epoxy resin modified with in situ generated metal oxides by means of sol–gel process

Organic–inorganic hybrids were prepared with silica, zirconia, or titania in situ generated within epoxy resins based on bisphenol A diglycidyl ether and Jeffamine® by means of the aqueous sol–gel process. The morphology of the prepared hybrids varied from a particulate dispersed phase to a co‐continuous morphology. Silica and zirconia filled epoxies were characterized by a significant increase in thermal stability, attributable to the high thermal stability of silica and zirconia phases. On the contrary, the introduction of titania induced a strong decrease in thermal stability of the epoxy/titania hybrids compared with the pure epoxy resin, attributable to metal‐catalyzed oxidative decomposition mechanism in the polymer/titania composite. Hybrids were much more transparent than unfilled epoxy. The transmittance of silica‐ and titania‐based hybrids showed a slight decrease by increasing the content of filler, while the transparency of zirconia‐based hybrids was very high and almost constant independently by the nominal content of filler. The presence of in situ generated fillers significantly enhanced the scratch resistance of the epoxy resin as indicated by the marked increase of critical load for all the hybrids. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

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     

Synthesis and characterization of nanocomposite of polyimide–silica hybrid from nonaqueous sol–gel process

Polyimide–silica (PI–SiO₂) hybrids with a nanostructure was obtained using the nonaqueous sol–gel process by polycondensation of phenyltriethoxysilane in a polyamic acid solution. Self‐catalyzed hydrolysis of phenyl‐substituted akoxysilane and modification on the polyimide structure are applied and result in highly compatible PI–SiO₂ hybrids. Transparent PI–SiO₂ with a high silica content of about 45% was thus obtained. The prepared PI–SiO₂ films were characterized by infrared spectrometry, ²⁹Si‐NMR, thermogravimetric analysis, differential scanning calorimetry, and scanning electron microscopy. These characterizations showed the silica influence on the properties of the hybrid. The thermal expansion coefficient of the PI–SiO₂ and the temperature correlation were also established for probing the potential for application. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 1609–1618, 2000     

Preparation and characterization of epoxy resin modified with alkoxysilane‐ functionalized poly(urethane‐imide) by the sol–gel process

The sol–gel process has been frequently employed for preparation of high performance silica/polymer composites. In this paper, novel sol–gel precursor triethoxysilane‐terminated poly(urethane‐imide) (PUI‐Si), combining the advantages of polyurethane (PU) and polyimide, was synthesized and characterized. Then PUI‐Si was incorporated into the epoxy resin matrix to prepare a series of EP/PUI‐Si organic‐inorganic hybrids through an in situ sol–gel process and crosslinking reactions. The thermal stability of EP/PUI‐Si hybrids was evaluated by thermogravimetric analysis and the results show that the PUI‐Si could significantly improve the thermal properties of epoxy resin. The initial decomposition temperature of composites with 50 wt% PUI‐Si reached 347.1 °C, 157.3 °C higher than that of neat epoxy resin. Furthermore, the tensile strength and breaking elongation can also be clearly improved by adding a suitable amount of PUI‐Si. Similarly, the water contact angle increased to 97.4° with 70 wt% PUI‐Si, showing a hydrophobic surface. The morphology was investigated by transmission electron microscopy and the results reveal that the silica particles are smaller than 20 nm and have a strong interaction with the epoxy resin matrix, resulting in the above‐mentioned high performance properties. Copyright © 2011 Society of Chemical Industry