Preparation of poly(methyl methacrylate‐co‐maleic anhydride)/SiO2?TiO2 hybrid materials and their thermo‐ and photodegradation behaviors

The optically transparent poly(methyl methacrylate‐co‐maleic anhydride) P(MMA‐co‐MA)/SiO₂? TiO₂ hybrid materials were prepared using 3‐aminopropyl triethoxysilane as a coupling agent for organic and inorganic components. Real‐time FTIR was used to monitor the curing process of hybrid sol, indicating that imide group formation decreased with increasing titania content. scanning electron microscopy, atomic force microscopy, and differential scanning calorimetry results confirmed their homogeneous inorganic/organic network structures. TGA analysis showed that incorporated titania greatly prohibits the thermodegradation of hybrid films, especially at the content of 5.3 wt %, showing an increase of about 32.6°C at 5% loss temperature in air. The UV degradation behavior of P(MMA‐co‐MA) studied by quasi‐real‐time FTIR showed that TiO₂ incorporated in the hybrid network provides a photocatalytic effect rather than a UV‐shielding effect. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1714–1724, 2005     

Photocatalytic properties of PMMA‐TiO2 class I and class II hybrid nanofibers obtained by electrospinning

The preparation, characterization, and photocatalytic activity evaluation of three hybrid fibrous materials composed mainly by poly(methyl methacrylate) (PMMA), methyl methacrylate (MMA): 3‐(trimethoxysilyl) propyl methacrylate (TMSPM): titanium butoxide (TBT), TiO₂ nanoparticles (NPTiO₂), and TiO₂ nanowires (NWTiO₂) is studied. Two types of fibe?s structures were prepared, single and core‐shell structures. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis showed both structures, single and core‐shell, as well as the inorganic phase were dispersed in the hybrid fibers. Infrared spectroscopic analysis (FT‐IR) and thermal analysis showed the organic and inorganic components, as well as the weight percentage of the inorganic phase present in hybrid fibers. The photocatalytic activity of the hybrid fibers class I and II showed that the best photodegradative efficiency for methylene blue in aqueous solution (2.9 × 10^?5 M) was 95%, provided by PMMA—10 wt % NPTiO₂. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44334.     

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     

Phase‐separation prevention and performance improvement of poly(vinyl acetate)/TEOS hybrid using modified sol‐gel process

The formation of covalent bonds between silanols in copolymer and those in silica prevents organic–inorganic phase separation. Two series of hybrid composite materials, poly(vinyl acetate‐co‐vinyl trimethoxysilane)/TEOS and poly[vinyl acetate‐co‐3‐(trimethoxysilyl)propyl methacrylate]/TEOS, were fabricated using a modified sol‐gel process. The hybrids were transparent. Two kinds of silane coupling agents, vinyl trimethoxysilane (VTS) and 3‐(trimethoxysilyl)propyl methacrylate (γ‐MPS), were used to prevent macrophase separation through formation of covalent bonds. Thermal analysis showed that γ‐MPS was more effective than VTS for the formation of covalent bonds. Enhancement of thermal stability of the hybrids was investigated by thermogravimetric analysis. Photomicrographs of scanning electron microscopy and images of atomic force microscopy indicated that inorganic silica particles were homogeneously dispersed in less than 50 nm in organic matrix. The morphological properties of hybrids were strongly dependent on the organic–inorganic composition. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2310–2318, 2001     

Study on the optical properties of sulfur‐containing poly(methyl methacrylate)‐inorganic hybrid

High refractive index homogeneous hybrid materials were successfully prepared. The polymer matrix was the copolymer of methyl methacrylate, sulfur‐containing monomer 2,2′‐mercaptoethylsulfide dimethacrylate (MESDMA), and nanotitania was prepared by in situ solgel process of titanium n‐butoxide. The transmission electron microscope (TEM) study suggested that the hybrid was homogeneous without inorganic agglomerate, and the inorganic particles were 4–7 nm. The refractive index was ～ 1.75 when the inorganic content of the hybrid film reached to 70 wt %, and the transmittance maintained up to 85%. The sulfur‐containing monomer was used to improve the refractive index, also, it was a crosslinking reagent, which improved the film‐forming ability of the hybrid. After copolymerized with MESDMA, the film‐forming ability of the hybrid was better than the one without MESDMA. Even if the inorganic content exceeded 75 wt %, the films kept integrity. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Role of silane coupling agents for performance improvement of poly(vinyl acetate)/tetraethyl orthosilicate hybrid composites prepared by a sol–gel process

Silica based poly(vinyl acetate)/inorganic hybrid composites were prepared via a sol–gel process under acidic conditions. Because the phase behaviour of the hybrids is greatly affected by weak interactions such as hydrogen bonding between organic polymer and inorganic network, two types of silane coupling agent (vinyl trimethoxysilane and 3‐(trimethoxysilyl)propyl methacrylate) were used to introduce specific interactions and to control phase behaviour in the interface between polymer and silica. The interfacial interactions between polymer and inorganic segment in the presence of silane have been investigated by Fourier transform infrared spectroscopy. Thermogravimetric analysis shows that the thermal stability of organic components in the hybrids is enhanced by addition of silane coupling agents. Scanning electron micrographs reveal that silica particles are homogeneously dispersed in the organic matrix as a result of the specific interactions. © 2001 Society of Chemical Industry     

Preparation of titanium dioxide/polyacrylate nanocomposites by sol–gel process in reverse micelles and in situ photopolymerization

UV‐curable, transparent acrylic resin/titania organic–inorganic hybrid films were prepared by controlled hydrolysis of titanium tetrabutoxide in Span‐85/Tween 80 reverse micelles and the subsequent in situ photopolymerization of the acrylic monomers. UV–vis spectra and atomic force microscopy (AFM) indicated the presence of a nanoscale hybrid composition. The onset of absorption (λ_onset) of titania in the hybrids appeared between 363.4 and 383.5 nm, which exhibited blue shifts relative to that of bulk anatase (λ_onset = 385 nm). The titania content increased rapidly at higher temperature and higher TTB content, whereas it increased slowly with longer post‐thermal treatment times. The refractive index and UV shielding properties of the organic polymer were obviously improved with increasing titania content. AFM images showed the inorganic domains (mean size 25.3–28.8 nm) were uniformly dispersed in the polymeric networks. The roughness parameters of the hybrid material were: toughness, 1.5–2.3 nm; root mean square roughness, 4.5–4.6 nm; and peak and valley distance, 9.7–19.4 nm. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5105–5112, 2006     

Thermal and optical properties of PMMA–titania hybrid materials prepared by sol‐gel approach with HEMA as coupling agent

A series of sol‐gel derived organic–inorganic hybrid materials consisting of organic poly(methyl methacrylate) (PMMA) and inorganic titania (TiO₂) were successfully synthesized by using 2‐hydroxyethyl methacrylate (HEMA) as coupling agent. In this work, HEMA is first copolymerized with methyl methacrylate monomer at specific feeding ratios by using benzoyl peroxide (BPO) as initiator. Subsequently, the as‐prepared copolymer (i.e., sol‐gel precursor) is then cohydrolyzed with various contents of titanium butoxide to afford chemical bondings to the forming titania networks to give a series of hybrid materials. Transparent organic–inorganic hybrid materials with different contents of titania are always achieved. Effects of the material composition on the thermal stability, optical properties, and morphology of neat copolymer and a series of hybrid materials, in the form of both coating and free‐standing film, are also studied by differential scanning calorimetry, thermogravimetric analysis, UV–Vis transmission spectra, refractometer, and atomic force microscopy, respectively. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 400–405, 2004     

Synthesis and characterization of fluorinated organic–inorganic hybrid coatings on tinplate

Fluorinated organic–inorganic hybrid coatings with interpenetrating network for corrosion protection of tinplate were prepared by hydrolysis and condensation reaction of tetraethoxysilane and 3‐methacryloxypropyltrimethoxysilane, followed by radical polymerization of trimethylolpropane triacrylate dodecafluoroheptyl methacrylate. The highly crosslinked organic network was developed and attached to the inorganic moieties through covalent Si–C bonds. The hybrid coatings were characterized by scanning electron microscope, water contact angle, Fourier transformed infrared spectroscopy, and thermogravimetric analysis. Their anticorrosion performances were evaluated by potentiodynamic polarization, electrochemical impedance spectroscopy and salt spray test. The results indicated that the fluorinated hybrid coatings exhibited excellent anticorrosion ability by forming a hydrophobic physical barrier between tinplate substrate and its external environment. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42428.     

Study of the organic-inorganic phase interactions in polyester-titania hybrids

Radiopaque organic-inorganic hybrids were prepared by the sol-gel procedure. The hybrid the organic phase is a polyester, poly(1,4-butyleneglutarate), while the inorganic domains are in situ synthesized titania. FT-IR and XPS analyses show that organic and inorganic phases strongly interact mainly because of transesterification reactions involving the polyester chain and Ti atoms during hybrid synthesis. Synthetic parameters, namely solvent, environment acidity and inorganic precursor content, are investigated in order to assess their influence on the solid-state behaviour of the hybrid. The ability of the solvent to solvate, but not complex, Ti atoms and the presence of an inorganic acid in the feed increase interaction between the organic and inorganic phases, thus hindering polymer chain mobility. A similar effect, outlined by T_g increase and crystallization inhibition, is induced by increasing inorganic phase content. All obtained hybrids are optically transparent and opaque to X-rays.     

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     

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     

Water absorption and disc cracking in urethane–methacrylate resins

Water absorption at 23 and 100°C has been studied in three materials based on a single type of urethane–methacrylate resin: the neat resin, a rubber-toughened blend containing 15 wt % of core-shell modifier, and a filled rubber-toughened resin containing 46 wt % silica plus 8 wt % core-shell modifier. In all six absorption experiments, water diffusion followed Fick's law. However, in neat resin at 100°C, the period of Fickian diffusion, during which the material appeared to reach saturation, was followed by an additional period of water uptake, which was accompanied by formation of internal disc cracks up to 1 mm in diameter. At both 23 and 100°C, fracture of water-saturated neat resin was defect dominated: cracks were initiated at inorganic impurities between 40 and 80 μm in diameter. The adverse effects of water are attributed to hydration and consequent swelling of these insoluble impurities. No internal cracking was detected in either the rubber-modified or hybrid resin, which have higher a K_ICs than the neat resin. © 1994 John Wiley & Sons, Inc.     

Free‐standing hybrid anion‐exchange membranes for application in fuel cells

A series of free‐standing hybrid anion‐exchange membranes were prepared by blending brominated poly(2,6‐dimethyl‐1,4‐phenylene oxide) (BPPO) with poly(vinylbenzyl chloride‐co‐γ‐methacryloxypropyl trimethoxy silane) (poly(VBC‐co‐γ‐MPS)). Apart from a good compatibility between organic and inorganic phases, the hybrid membranes had a water uptake of 32.4–51.8%, tensile strength around 30 MPa, and T_d temperature at 5% weight loss around 243–261°C. As compared with the membrane prepared from poly (VBC‐co‐γ‐MPS), the hybrid membranes exhibited much better flexibility, and larger ion‐exchange capacity (2.19–2.27 mmol g^?1) and hydroxyl (OH^?) conductivity (0.0067–0.012 S cm^?1). In particular, the hybrid membranes with 60–75 wt % BPPO had the optimum water uptake, miscibility between components, and OH^? conductivity, and were promising for application in fuel cells. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Proton conducting membranes based on sulfonated poly(ether ether ketone)/TiO2 nanocomposites for a direct methanol fuel cell

This paper presents an evaluation of the effects of titanium dioxide nanoparticles in sulfonated poly(ether ether ketone) (SPEEK) with a sulfonation degree of 57%. A series of inorganic/organic hybrid membranes was prepared with a systematic variation of titanium dioxide nanoparticle content. Their water uptake, methanol permeability and proton conductivity as a function of temperature were investigated. The results obtained show that the inorganic oxide network decreases the proton conductivity and water swelling. It is also found that increasing the inorganic oxide content leads to a decrease of methanol permeability. In terms of morphology, the membranes are homogeneous and exhibit good adhesion between inorganic domains and the polymer matrix. The proton conductivity and fuel cell performances of the nanocomposite membranes showed very good prospective in direct methanol fuel cell usages. The properties of the composite membranes are compared with those of standard Nafion membranes. Copyright © 2006 Society of Chemical Industry     

Effect of acrylic monomer content on the properties of waterborne poly(urethane‐urea)/acrylic hybrid materials

Stable waterborne poly(urethane‐urea) (WBPU; soft segment content: 57%; dimethylol propionic acid: 19 mol %/5.8 wt %)–polyacrylate(methyl methacrylate/n‐butyl acrylate) (weight ratio: 4/1) hybrid latex (emulsions) with different acrylic contents [0, 10, 20, 30, and 40 wt % based on poly(urethane‐urea)] and without external surfactant were successfully prepared by in situ polymerization during a prepolymer mixing process. However, the as‐polymerized hybrid latex containing 50 wt % of acrylic monomer content was found to be unstable, indicating that about 50 wt % of acrylic monomer content was beyond the limit value of self‐emulsifying ability of WBPU anionomer prepared in this study. The breadth of particle size distribution of hybrid latex increased markedly from 20–75 to 55–275 nm with increasing acrylic monomer content from 0 to 40 wt %. The pristine WBPU and hybrid latex samples containing 10, 20, and 30 wt % of acrylic monomer showed unimodal distributions, whereas the hybrid sample having 40 wt % acrylic monomer content displayed a bimodal distribution with the broadest breadth. As acrylic monomer content increased, the yield point of stress–strain curve, hardness, glass transition, and water resistance of hybrid film samples increased, whereas their abrasion resistance, elongation at break, and elasticity decreased. The tensile strength of hybrid film samples (10–30 wt % of acrylic monomer content) was almost the same as that of pristine WBPU film sample, indicating the intimate molecular mixing between poly(urethane‐urea) and polyacrylate molecules in hybrids. However, the hybrid sample having 40 wt % acrylic monomer showed significantly diminished performance, which might be due to the deviation from intimate molecular mixing. From these results, the optimum acrylic monomer content was found to be about 30 wt %, which realized reasonably advantages of both poly(urethane‐urea) and acrylic polymer. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Cationic hybrids from poly(N,N‐dimethylaminoethyl methacrylate) covalently crosslinked with chloroalkyl silicone derivatives effective in binding anionic dyes

The synthesis and characterization of some novel ionic organic/inorganic hybrids containing quaternary ammonium salt groups in the side chain, built on the basis of poly(N,N‐dimethylaminoethyl methacrylate), as an organic component and cation provider, and chloroalkyl‐functionalized silicone derivatives as crosslinkers and anion generators, are reported in this work. The resulted structures were investigated using Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, and energy dispersive X‐ray spectroscopy. The swelling behavior of the ionic hybrids in water as a function of pH as well as the water vapor sorption capacity in dynamic regime was also studied. The cationic hybrids have a higher swelling capacity at pH 2 compared with deionized water (pH 6) due to the presence of tertiary amine groups belonging to the organic compound. The ionic organic/inorganic hybrids were tested as potential sorbents for anionic species such as dyes [e.g., methyl orange (MO)]. The equilibrium sorption capacity increased with the increase of the organic component up to around 32 mg MO/g hybrid. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43942.     

Polydimethylsiloxane (PDMS)-based antibacterial organic–inorganic hybrid coatings

UV-curable antibacterial organic–inorganic hybrid coatings were prepared by sol–gel method. Triethoxysilane-terminated poly(dimethylsiloxane) (TESi-PDMS) as a new coupling agent to improve the compatibility between organic and inorganic phases was synthesized. PDMS-based urethane methacrylate oligomer was obtained by reacting isophorone diisocyanate with hydroxyethyl methacrylate and hydroxyl-terminated PDMS. The formulations were applied onto polycarbonate panels and then cured by UV radiation. Physical properties of UV-cured free films such as gel content, stress–strain, and conversion of acrylate double bond were examined. In addition, the antibacterial effects of the coatings were investigated. Nanosilver-containing formulations exhibited high antibacterial effect against Escherichia coli and Staphylococcus aureus. Thermogravimetric analysis indicated that thermal stability of the hybrids was significantly higher than the organic polymer. Contact angle measurement showed that addition of silane precursor increased the contact angle from 95° to 110°.     

Synthesis and characterization of flame retarding UV‐curable organic–inorganic hybrid coatings

UV‐curable, organic–inorganic hybrid materials were synthesized via sol–gel reactions for tetraethylorthosilicate, and methacryloxypropyl trimethoxysilane in the presence of the acrylated phenylphosphine oxide resin (APPO) and a bisphenol‐A‐based epoxy acrylate resin. The sol–gel precursor content in the hybrid coatings was varied from 0 to 30 wt %. The adhesion, flexibility, and hardness of the coatings were characterized. The influences of the amounts of inorganic component incorporated into the coatings were studied. Results from the mechanical measurements show that the properties of hybrid coatings improve with the increase in sol–gel precursor content. In addition, thermal properties of the hybrids were studied by thermogravimetric analysis in air atmosphere. The char yield of pure organic coating was 32% and that of 30 wt % silicate containing hybrid coating was 30% at 500°C in air atmosphere. This result demonstrates the pronounced effect of APPO on the flame retardance of coatings. Gas chromatography/mass spectrometry analyses showed that the initial weight loss obtained in thermogravimetric analysis is due to the degradation products of the photoinitator and the reactive diluent. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1906–1914, 2006     

Synthesis and properties of PMMA‐ZrO2 organic–inorganic hybrid films

In this work we report the synthesis process and properties of PMMA‐ZrO₂ organic–inorganic hybrid films. The hybrid films were deposited by a modified sol‐gel process using zirconium propoxide (ZP) as the inorganic (zirconia) source, methyl methacrylate (MMA) as the organic source, and 3‐trimetoxy‐silyl‐propyl‐methacrylate (TMSPM) as the coupling agent between organic and inorganic phases. The films were deposited by dip coating on glass slide substrates from a hybrid precursor solution containing the three precursors with molar ratio 1 : 0.25 : 0.25 for ZP, TMSPM, and MMA, respectively. After deposition, the hybrid thin films were heat‐treated at 100°C for 24 h. The macroscopic characteristics of the hybrid films such as high homogeneity and high optical transparence evidenced the formation of a cross‐linked, interpenetrated organic–inorganic network. The deposited PMMA‐ZrO₂ hybrid films were homogeneous, highly transparent and very well adhered to substrates. Fourier Transform Infra‐Red measurements of the hybrid films display absorption bands of chemical groups associated with both PMMA and ZrO₂ phases. The amounts of organic and inorganic phases in the hybrid films were determined from thermogravimetric measurements. The surface morphology and homogeneity of the hybrid films at microscopic level were analyzed by scanning electron microscopy and atomic force microscopy images. From the analysis of optical transmission and reflection spectra, the optical constants (refraction index and extinction coefficient) of the hybrid films were determined, employing a physical model to simulate the hybrid optical layers. The refraction index of the hybrid films at 532 nm was 1.56. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42738.