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The present paper studies the effect of polyaniline grafting on magnetite functionalized with aminopropyltrimethoxysilane. All the compounds were characterized by analytical techniques (X-ray fluorescence, X-ray diffraction, Fourier transform infrared spectroscopy, thermal analysis, Transmission electron microscopy), as well as by determining their magnetic properties. The electron microscopy analysis of the hybrids shows similar morphologies for all the samples. The presence of the iron atoms on the surface of the final product supports the idea of the existence of an inverted core-shell type structure, the more polar ferrite orienting itself towards water. The correlation between the maximum grafting probability and the maximum magnetization is evidenced, demonstrating the importance of the polymer grafting method on the magnetic properties.

Sol-gel derived organic-inorganic hybrid systems were obtained by applying alkaline-catalyzed co-hydrolysis and copolycondensation reactions of tetraethoxysilane (TEOS), methyltriethoxysilane (MTES), isobutyltriethoxysilane (IBTES), diethoxydimethylsilane (DMDES), and vinyltriethoxysilane (VTES), respectively, into a polymer latex functionalized with vinyltriethoxysilane (VTES). The properties of the latex hybrid materials were analyzed by FTIR, water contact angle, environmental scanning electron microscopy (ESEM), TEM and AFM analysis, respectively. FT-IR spectra confirmed that the chemical structures of the sol-gel derived organic-inorganic materials are changed as function of inorganic precursor and Si O Si networks are formed during the co-hydrolysis and copolycondensation reactions. The water contact angle on the sol-gel latex film containing TEOS + VTES increased to 135° ± 2 compared to 65° ± 5 for the blank latex, due VTES incorporation into latex material. TGA curves of hybrid sample modifies against neat polymer, the thermal stability being influenced by the presence of the inorganic partner. ESEM analysis showed that the latex hybrid films prepared with different inorganic precursors were formed and the Si-based polymers were distributed on the surface of the dried sol-gel hybrid films. TEM and AFM photos revealed that the latex emulsion morphology was modified due to the VTES incorporation into system.

This paper debates the effect of the stabilizer (vinyl benzyl trimethyl ammonium chloride—VBTAC or cetyl trimethyl ammonium chloride—CTAC) and the structure (typical SiO2 matrix or inorganic–organic interpenetrated matrix) influence in molecular imprinting of gallic acid-polyphenol class of templates. For this purpose, gallic acid-imprinted particles were obtained via typical polycondensation sol–gel reactions and via sol–gel/radical polymerization concurrent reactions of tetraethoxy silane (TEOS) and aminopropyl ethoxy silane (APTES) or vinyl triethoxy silane (VTES), respectively. The influence of the mesophase formation and stabilizer nature upon the re-binding of gallic acid was investigated using thermal, infrared and morphology measurements. Adsorption assays of organosilica particles were well correlated with their physical properties. Unlike the polycondensation of TEOS with APTES in the presence of CTAC, concurrent radical polymerization of VBTAC consumed the vinyl functionalities of VTES, decreasing the capacity of VBTAC to mediate the mesophase formation and the capacity of VTES to coordinate template molecules; hence, both the binding capacity and the “memory” effect of the interpenetrated organosilica structure were significantly affected.

The radical polymerization of aniline hydrochloride (ANIHCl) in the presence of ammonium persulfate was studied. 1D-Polyaniline (PANI) with fibrillar morphologies was obtained in the presence of anionic surfactants. The changes of the PANI-template structures in aqueous solution were studied using static fluorescence measurements. The dispersed PANI nanoparticles were characterized using dynamic light scattering, scanning electron microscopy (SEM), and Raman and Fourier transform infrared spectroscopies. The thermal analysis and the electrical conductivity of the dried samples were also performed. The fluorescence measurements indicated that nanocrystals of ANIHCl form in water complexes with the anionic surfactants at smaller concentrations than the critical micellar concentration. The same method revealed that other organic complexes with sulfonate groups do not induce an increase of the hydrophobic region due to short hydrocarbon tails. The SEM micrographs and Raman spectra revealed that the PANI nanofibers are compact and different compared to the nanoparticles prepared without surfactants.

Thermogravimetric analysis (TG), derivative thermogravimetry (DTG), differential scanning calorimetry (DSC), dynamic mechanical thermal analysis, simultaneous differential thermogravimetry (SDT) coupled with mass spectrometry (MS), and pyrolysis coupled with gas chromatography/mass spectrometry (Py-GC/MS) were used to characterize molecularly imprinted polymers (MIPs) obtained with two anti-cancerous template molecules, diosgenin and sclareol, imprinted in acrylonitrile–acrylic acid copolymer matrices. First of all, TG analyses revealed a specific mass loss in the temperature range 220–300 °C characteristic to diosgenin-MIPs, while for the sclareol-MIPs, the specific interval was 100–240 °C. Further, the DSC analyses evidenced two major aspects: first, that the copolymer matrices have a single glass transition temperature (T g), which confirms the random statistic copolymer structure, an essential characteristic of a homogenous MIP matrix; secondly, both templates influence the T g values of the MIPs, fact that is an additional proof of molecular imprinting. The SDT results confirmed the TG and DSC results and, additionally, proved that the system with higher acrylic acid content generates stronger template–matrix interactions via hydrogen, van der Waals, and other non-covalent forces, fact that appears as an increased thermal stability on the TG curve and a higher maximum for template decomposition on the DTG curve. The MS results evidenced that a single mass fragment, 139 ± 1 m/z, characteristic for the class of steroid sapogenines of which diosgenin belongs, is enough to prove, qualitatively and quantitatively, the molecular imprinting and the template elution. As global conclusion, the applied thermal analyses proved to be exceptional tools for analyzing these molecularly imprinted polymers.

In this research, both commercially available (Cloisite 93A) and advanced functionalized clay mineral were used to obtain clay–epoxy nanocomposites. Cloisite 93A was modified with three different alkoxysilanes and was incorporated in Epon 862 epoxy resin which was crosslinked using tetraethylenepentamine as a curing agent. The determination of color grades of the composite samples was followed. The morphology of the composites was analyzed using X-ray diffraction and ESEM micrographs which provided insight into the fracture mechanism. Thermal behavior was evaluated by TGA and DSC and thermo-mechanical properties of the cured samples have been evaluated by DMA technique. The data indicated that intercalated or agglomerated silylated Cloisite–epoxy nanocomposites were obtained. The silylated Cloisite samples are more compatible with the polymer matrix due to their enhanced hydrophobic behavior leading to an improvement in storage modulus and stiffness but also to the increase of glass transition temperature up to 30 °C.

Obtaining composite materials based on multiwalled carbon nanotubes (MWCNT) from water dispersion is viable nanotechnology with low impact on the environment and with concrete directions for advanced materials used in coating application. Emulsion, miniemulsion, or microemulsion polymerization techniques can offer by their nature the reducing of the interfacial tension (between MWCNTs and monomers). By free radical polymerization, MWCNT-polymer composites can be obtained in a greener manner by cutting off several supplementary technological steps involved by functionalizing (toxic reagents, energy consuming), solvent phase purification, and separation of the fillers. Providing such examples involving large tonnage polymers like polystyrene, SAN copolymer, polyacrylonitrile, poly(methyl methacrylate) and other, a detailed picture of the state of the art can be achieved for synthesis and application in automotive industry, aerospace, coating materials, antistatic materials, sensors, actuators, membrane production, fibers industry, and others. The chapter tries to answer to some technological bottlenecks: decreasing the environment impact and extending the areas of application by reducing the costs of MWCNTs processing for polymer composites as a natural step for the sustainable development of an MWCNT-composite industry.

The stability of the organosilica–gallic acid (GA) complex, and thus the strength of initial interactions which influences directly the sorption parameters of imprinted materials, is mostly given by the nature of co-monomers. Therefore, combining tetraethoxysilane, tetrametoxysilane, vinyl triethoxysilane and vinyl benzyl triethoxysilane as functional monomers, six formulations were obtained in order to optimise the nature of imprinted sieves. Vinyl benzyl trimethylammonium chloride and tertamethyl ammonium hydroxide directed the mesophase formation. Morphology and thermal properties of imprinted organosilica sieves were evaluated and compared to those of blank polymers synthesised in the same conditions as the imprinted ones but without GA. Thermal analysis results corroborated with the morphology of imprinted sieves were confirmed by specific GA sorption tests.

The increased interest in silica nanowires for nanophotonics, mechanical applications, microsurgery, chemical and biological sensors strongly motivates the search for new discoveries involving complex silica nanowire-clay mineral layers (SiNW), particularly focusing on their growth mechanism, their involvement during polymer synthesis and the generation of a new class of polymer nanocomposites. This paper addresses the major findings involving the growth mechanism of silica nanowires on the clay mineral layers as well as their high segmental mobility and influence on the kinetics of butylacrylate mini-emulsion radical polymerisation. The growth mechanism for the silica nanowires was a sol-gel process involving tetraethylorthosilicate at the edge groups of the clay layers after blocking the reactive sites with a monofunctional alkoxysilane. To demonstrate the mobility of the network, an indirect method was utilised, specifically the interaction between the ethoxylated molecules and Tween 60. No cross-linking side effects occurred in the silica nanowires. SiNW enhance the free radical polymerisation of butylacrylate in dispersed media, increasing the monomer conversion from 2.5% to 33%. The kinetics of the polymerisation process can be tuned by SiNW, modulating the system between emulsion- and mini-emulsion-like systems by acting on the pseudo-steady state interval of the radicals (10%–40% conversion).

Polymer-clay nanocomposites were synthesized by solution polymerization method using advanced functionalized clay and vinyl benzyl trimethyl ammonium chloride as monomer. First stage consisted in the silylation of a commercial organo-modified clay-Cl 20A using alkoxysilanes with different chain lengths. In the second step, the synthesis and characterization of polymer-nanocomposites were followed. To evaluate the clay functionalization process as well as the final polymer-clay products, thermogravimetric, X-ray diffraction, dynamic light scattering, Fourier transform infrared spectroscopy and three test liquid contact angles analyses were used. The loss of ammonium ions from commercial clay, the grafting degree, the lengths and the nature of alkyl chain influence the dispersion of the advanced modified clay into the polymer solution and, furthermore, the properties of the final polymer-clay nanocomposite film.

This paper reports the synthesis of coating silica particles, in order to design hybrid materials with hydrophobic surface properties. The silica particles were prepared in basic conditions under atmosphere of carbon dioxide (CO 2 ), using tetraethylorthosilicate (TEOS) as a precursor and octyltriethoxysilane (OTES) as a surface modifying agent. It was demonstrated that the contact angles of silica hybrid films could be changed by varying temperature and pressure of CO 2 . The investigation of the prepared hybrid materials by dynamic light scattering (DLS) and environmental scanning electron microscopy (ESEM), respectively, showed that they consisted mainly of particles with a diameter of 100–250 nm. Fourier transform infrared (FT-IR) spectra indicate that the interaction between the coupling reagents, at different conditions, is mainly through chemical bonding.

The objective of this study is to design new hybrid silica materials as templates with hydrophobic properties, prepared at room temperature by a base catalyzed sol–gel process. As silica sources, organoalkoxysilanes functionalized with short hydrophobic chains were used: tetraethylorthosilicate (TEOS), methyltriethoxysilane (MTES), vinyltriethoxysilane (VTES), octyltriethoxysilane (OTES) and isobutyltriethoxysilane (iTES). It was shown that hydrophobicity of the functionalized silica nanoparticles increased as a function of length of the aliphatic chains (MTES < iTES < OTES) or when, instead of a hydrophobic alkyl chains (substituting group of silica precursors), a monounsaturated group was used (VTES). It was observed that the samples responded in a specific way to each type (hydrophilic or hydrophobic) of the dropped liquid. Even though the experiments were limited to short hydrocarbon chains, they showed that there is a threshold to reach high hydrophobicity of the hybrid surface.

Hybrid thin films, silica–titanium oxides and silica–aluminum oxides, designed based on the sol–gel process are evaluated as catalysts in the photo-degradation of the cationic dyes. Silica matrices from different precursors with various organic functional groups and cross-linked with titanium or aluminum agents (tetraisopropyl orthotitanate and aluminum sec-butoxide) allow the surface property tailoring related to the high capacity of the dye adsorption respective, high photo-degradation activity. The cationic dyes (methylene blue, rhodamine B, crystal violet, malachite green) embedded on the hybrid silica matrix, under ultraviolet light, have a first order kinetics of photodegradation. The cross-linking agents play a key role in the photocatalytic degradation and silica matrix as dye absorbent. The photo-degradation rate for the binary system derived from methyltriethoxysilane/vinyltriethoxysilane precursors with both cross linkers showed a significant improvement by comparison with other hybrid materials. The significant increasing in the photodecomposition rate is related to the capacity to generate additional oxidizing species by each silica hybrid compounds.

In this report, we present the versatile and effective technique, using environmental friendly reductant glucose, to prepare stable silver nanodispersions by reduction of Ag+ ions. Alternant copolymers of maleic anhydride with vinyl acetate and styrene sulphonate sodium acid salt polyelectrolytes were synthesized in aqueous solution and used as stabilizers. The formation of nano silver particles was confirmed by UV-Vis spectrophotometry and TEM measurements. Dynamic Light Scattering (DLS) measurements were needed to study how the reagents and their concentrations influence particle size. SEM images show the nanostructure of the hybrid films and indicate a strong interaction between the polyelectrolyte and the silver NPs. Moreover, the silver NPs could be stored for one year without observation of aggregates or sedimentation. The final solid products obtained after evaporating to dryness can be used to produce stable dispersions upon mixing with water. Few of the final products were found to exhibit a high antibacterial and antifungal activity.

Ultra-hydrophobic bilayer coatings on a glass surface were fabricated by sol–gel process using hexadecyltrimethoxysilane (C16TMS) and tetramethoxysilane (TMOS) (1:4 molar ratio) as precursors. After coating, silica nanoparticles (SiO2 NPs) functionalized with different mono-alkoxy derivatives (methoxytrimethylsilane, TMeMS; ethoxydimethylvinylsilane, DMeVES; ethoxydimethylphenylsilane, DMePhES; and methoxydimethyloctylsilane, DMeC8MS) were added, assuring the microscale roughness on the glass surface. Influences of the functionalized SiO2 NPs and surface morphology on the hydrophobicity of the hybrid films were discussed. The successful functionalization of SiO2 NPs with hydrophobic alkyl groups were confirmed by Fourier transform infrared spectroscopy (FTIR). The thermal stability of hydrophobic SiO2 NPs showed that the degradation of the alkyl groups takes place in the 200–400 °C range. Bilayer coating with C16TMS/TMOS and SiO2 NPs modified with alkoxysilane substituted with C8 alkyl chain (SiO2 NP-C8) has micro/nano structure. Hydrophobicity of functionalized SiO2 NPs-C8 and its higher degree of nanometer-scale roughness gave rise to ultra-hydrophobicity performance for bilayer coating C16TMS/TMOS + SiO2 NPs-C8 (145°), compared to other similar hybrid structures. Our synthesis method for the functionalization of SiO2 NPs is useful for the modification of surface polarity and roughness.

Liquid crystals/magnetic particles composites have been shown to exhibit very interesting behaviors when subjected to different external fields, finding new applications in the field of functional nanomaterials. We present a new colloidal composite formed by combining polymer-magnetite nanoparticles and a lyotropic nematic liquid crystals. TEM investigations on the polystyrene magnetite show magnetite nanocrystals anchored in polymeric chains. The optical transmission of the ferronematic was investigated when the samples were subjected to different values of static magnetic field and the critical magnetic field corresponding to the Freedericksz transition was estimated.

Bulk and microemulsion systems were studied in order to obtain molecularly imprinted copolymers selective for gallic acid. Both systems contained acrylic acid as the functional monomer and ethylene glycol dimethacrylate as crosslinker. Microemulsion formation was confirmed by refractive index measurements and by conductivity analyses. Simple uptake tests revealed higher affinities for the microemulsion polymers; a 3.55 imprinting factor and a 0.275 g gallic acid (g polymer)–1 adsorption capacity were recorded. Competitive uptake tests, from an oak bark extract, were in agreement with the simple uptake results and BET analyses. Microemulsion polymer particles selectively bind 4.58 times more gallic acid molecules relative to other competitor species.

Magnetite alternating copolymers divinylbenzene–maleic anhydride (DVB–MA) composites were prepared by dispersion polymerization. Because magnetite is used as a complex with oleic acid (Fe3O4OLA), the final hybrids show good dispersion of inorganic nanofillers in the polymer matrix. The obtained composites were analyzed by infrared absorption spectrometry, diffuse reflectance in visible light, thermogravimetry, X-ray fluorescence, X-ray diffraction, dynamic light scattering, scanning electron microscopy and vibrating sample magnetometry. The obtained results indicate the successful preparation of magnetite nanoparticles with an average size of about 23 nm dispersed in micrometer size copolymer spherical particles, which relative content can be controlled via the processing parameters. A relationship between the relative content of magnetite nanoparticles and the size of the polymer particles, with direct influence on the diffuse reflectance in the visible domain, was observed. A superparamagnetic behavior was evidenced at room temperature with a blocking temperature lower than as expected from the bulk anisotropy constant and the average size of the magnetite nanoparticles. Both the unexpected low blocking temperature and the observed low specific magnetizations were explained by a defected and poor crystalline structure of the magnetite nanoparticles, giving rise to spin disorder and diminished crystalline anisotropy constant.

We report the synthesis of molecularly imprinted sorbents, selective for gallic acid. The particles were prepared by using acrylic acid, acrylonitrile, and hydroxyethyl methacrylate as functional monomers, whereas ethyleneglycol dimethacrylate and 1,4-buthanediol dimethacrylate were used as crosslinkers. Preparation and manipulation protocols were adjusted considering template's nature. To highlight the influence of monomer/crosslinker nature upon imprinted particles, the adsorption capacity, the imprinting factor, and the distribution and selectivity coefficients were calculated. An imprinting factor of 3.53 and a selectivity coefficient of 6.86 were found for hydroxyethyl methacrylate/ethylene glycol methacrylate system. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci. 2013

The paper deals with the rheological properties of epoxy resin additivated with organically modified montmorillonites, carbon nanotubes and nanocarbon. The paper also presents the influence of nanoadditives over composites mechanical properties. The epoxy polymer is diglycidyl ether of bisphenol A (DGEBA) and the curing agent is an aliphatic tetraamine. Organically modified montmorillonites Cloisite 30B and Cloisite 93A, MWCNTs and laser synthesized nanocarbon were used to synthesize nanocomposites by dispersing each in an epoxy resin. The dispersion was achieved through mechanical and sonic methods. The epoxy resin additivated with nanosized fillers was rheologically tested to study the dispersion influence. The sonic dispersion of nanoadditives is observed to drastically influence the rheological behavior of the suspensions. Newtonian fluid behavior disappears as the additive loading increases. The work mentions the influence of nanoadditives on the manufacturing process of epoxy /glass fibre and epoxy/ carbon fibre laminated composites.

Sodium montmorillonite (NaMMT clay) derivatives were encapsulated in polymer particles obtained through dispersion copolymerization of divinyl benzene (DVB) with maleic anhydride (MA). To evidence the effect of alkyl monoalkoxysilanes upon MMT reaction, a variety of MMT clay functional derivatives were investigated. Particles with an increased size of modified MMT clay dispersed in dichloromethane were obtained using alkyl monoalkoxysilanes with a longer hydrocarbon chain. Relatively long hydrocarbon chains can exhibit a low substitution degree of MMT clay with alkyl monoalkoxysilanes. MMT class with a low substitution degree leads in the presence of alkoxysilanes to particles with average size between 700 and 1200 nm, and when DVB–MA copolymer is added the particles size decreases (~480 nm). The influence of layered silicates on the thermal stability of DVB–MA copolymer as a function of the used vinyl siloxanes derivatives for functionalization of MMT, on one hand, and the nonlinear variation of refractive index of used silanes on the other hand, pointing out the autoassociation during initial reaction of substitution.

Polymer composites from polylactic acid (PLA) and two types of cellulose fibers obtained either by acid hydrolysis of microcrystalline cellulose (HMCC) or by mechanical disintegration of regenerated wood fibers (MF) were prepared and characterized. To enhance the compatibility of the cellulose fibers with PLA matrix, a surface treatment based on 3-aminopropyltriethoxysilane (APS) was performed. The Fourier Transform Infrared (FTIR) spectroscopy was used to determine the chemical groups involved in the surface modification reaction. The silanization treatment resulted in different modifications on both types of cellulose fibers because of their different structural and morphological characteristics. The composites were prepared by incorporating 2.5% of the treated or untreated HMCC and MF into a PLA matrix using a melt-compounding technique. An improved adhesion between the two phases of the composite materials was observed by scanning electron microscopy thanks to treatment. The dynamic mechanical thermal analyses showed that both untreated and silane treated fibers led to an improvement of the storage modulus of PLA in the glassy state. A higher enhancement of the storage modulus in the case of PLA/HMCC composites than the composites containing MF was obtained as a result of the high aspect ratio of these fibers which allows better matrix-to-filler stress transfer. Furthermore, the storage modulus of PLA composites was enhanced by silanization even at higher temperatures especially after thermal treatment. The cellulose fibers addition in PLA matrix modified significantly the relaxation phenomenon as observed in tan δ curves, emphasizing strongly modified molecular mobility of PLA macromolecules and crystallization changes. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers.

This paper describes a method to prepare silica particles able to encapsulate 3 different hydrophobic dyes: Disperse Red, Solvent Red and 2-{4-[4-(Benzyl-ethyl-amino)-phenylazo]-benzenesulfonyl}-ethanol (HESA). Dye doped silica particles were prepared by the sol–gel process in aqueous medium, with a base catalyst, using various concentrations of a “home made” surfactant (named NP9-Si). The surfactant is the addition byproduct of –OH groups of polyethylene glycol nonylphenyl ether Tergitol® NP-9 with -NCO groups from (3-isocyanatopropyl) triethoxysilane and was added to increase both the stabilization of the silica particles and the compatibility of the inorganic network versus the dopant (the aromatic dye). It was shown that there is an optimum range of the amount of surfactant which should be added in the sol–gel reaction system. If a higher amount of surfactant is used, it forms probably micelles which entrap the dye and prevent its encapsulation in the formed silica particles. Because the silica particles are designed to encapsulate systems containing aromatic derivatives (aromatic dyes) we used phenyltriethoxy silane and tetraethylorthosilicate as silica precursors. As coupling agent for the silica network we used a bis (trialkoxysilane) derivative—1,2-bis (triethoxy silyl) ethane.

New nanocomposites based on polyacrylates and five types of montmorillonites modified by edge covalent bonding, were obtained. The alkoxysilanic substituent strongly influenced the physical–chemical properties of the final material. All modified clay minerals exhibit a lower wettability compared to pure montmorillonite. FTIR and TGA analyses confirmed the incorporation of montmorillonite in the polyacrylate matrix. Rugged spherical particles indicated that the platelets were predominantly on the polymer particles.

Cellulose nanofibers were obtained from microcrystalline cellulose (MCC) by the action of hydrodynamic forces associated with ultrasound. Nanofibers isolated from MCC by applying different ultrasonication conditions were characterized to elucidate their morpho-structural features by field emission scanning electron microscopy, atomic force microscopy, X-ray diffraction, and dynamic light scattering. Several differences were observed regarding the size of the nanofibers obtained in different ultrasonic conditions, but no significant changes in the crystalline structure of cellulose nanofibers were detected. The obtained cellulose fibers were used at low levels (1 to 5 wt.%) as reinforcements in a poly(vinyl alcohol) (PVA) matrix. The mechanical and thermal properties of the PVA/cellulose fibers nanocomposites films were determined. The tensile strength and modulus of the PVA film were significantly improved by the addition of cellulose nanofibers. Slightly higher onset degradation temperatures were obtained for PVA composites in comparison to neat PVA, showing an increase of the thermal stability caused by the addition of cellulose fibers.

Nanocomposites of divinylbenzene-maleic anhidride (DVB-MA) copolymers were synthesized in aqueous medium by generating silver nanoparticles from AgNO3-NaBH4 reaction. SEM images evidence the forming of metal nanoparticles on the particles surface of DVB-MA copolymers. The copolymer particles have larger diameters in the presence of monoesther maleic of nonyl phenol ethoxylate or sodium montmorillonite than DVB-MA copolymer particles although the nanoparticles' forming is still possible. The average size and the Zeta potential of the hybrid particles decrease in water, toward the initial copolymers sustains the forming of nanocomposites with Ag nanoparticles on the surface.

The sol–gel synthesis strategies combined with the templated growth of organic–inorganic hybrid networks provide access to an immense new area of innovative multi-functional advanced materials. One possible way to prepare such new advanced materials is to encapsulate liquid active agents (such as monomers, dyes, catalysts and hardeners) in microcapsules. Silica microcapsules of tetraethylortosilicate (TEOS) and 3-(trimethoxysilyl)propyl methacrylate (MPTS) were prepared in a precursor-monomer/NH4OH water microemulsion system. Trimethylolpropane triacrylate (TMPTA)—a trifunctional monomer useful in manufacturing of coatings, inks and adhesives—and a corresponding photoinitiator (DAROCUR 1173) were entrapped inside the obtained microcapsules. MPTS was used to increase compatibility between TMPTA and the sol–gel precursors. As stability agent we added a “home made” product resulted from functionalization of poly (ethylene glycol) methyl ether (MPEG) with (3-isocyanatopropyl) triethoxysilane (NCOTEOS). Were obtained microcapsules containing incorporated monomer and having average particle size in range of 0.5–50 μm. Thermal analysis, morphology study and the increase of the silica microcapsules average diameter, measured by DLS technique confirm the monomer encapsulation.

Synthesis of nanocomposites based on polystyrene/polybutylacrylate with layered silicates using emulsion polymerization procedure in aqueous medium allowed obtaining stable nanolatexes with sodium dodecyl sulfate as surfactant. Monomer and layered silicate nature influences the average diameter of the particles and the zeta potential appeared on the particle-disperse medium interface, as it was shown by dynamic light scattering analyses. In order to evidence the layered silicate structure, two structural evaluation methods were used. A new approach was used based on Fourier transform infrared analyses as a method to asses the clay delamination. The method was followed in conjunction with X-ray diffraction patterns and showed the pronounced delamination of the clay in the polymer matrix. The thermal stability was investigated by thermogravimetric analyses and the morphologies in solid state observed by environmental scanning electron microscope measurements.

We examined the electrical and optical properties of a new material containing polymer–clay nano-composite dispersed in a nematic liquid. The clay (Cloisite-type) was modified by copolymerization of maleic anhydride and divinyl benzene, using azobisisobutytironitrile as the initiator. The final polymer–clay nano-composite has an intercalated structure according to XRD patterns. We measured the thermally stimulated depolarization currents and determined the activation energies. Simultaneously we measured the optical transmission and we studied the influence of the previously applied polarizing electric fields.

Polymer nanocomposites (PNCs) ,namely, nanoparticles dispersed in a polymer matrix, have garnered academic and industrial interest since 1990. This is due to the very attractive properties of nanostructurated fillers, as carbon nanotubes, laser synthesized nanocarbon and layered silicates; PNCs do not expand the performance space of traditional filled polymers, but introduce new properties, low volume additions (1÷5 %) of nanoparticles such as carbon nanotubes and montmorillonite providing properties and enhancements comparable to those achieved by conventional loadings (15-40%) of traditional fillers [1]. Most important, tough, are value –added such as reduced permeability, flame retardant, increased resistance to oxidation and ablation. Also, the effect of carbon nanotubes on grain boundary sliding in zirconia policrystals as re- reentry shield, or thermal barrier [2]represents a matter of interest. Multifunctional composites are materials with carbon fibre or glass fibre as reinforcing networking in nanoaditivated polymer matrix. In aerospace technique these may be antistatic, antilightning, anti radar protectors, as paints, laminates and as sandwich structure. Though the most important application of nanocomposites is their usability in the engineered structural composites. The work presents a partial synthesis of researches performed in this field by the consortium INCAS, INFLPR, ICECHIM, Ovidius University within the CEEX Programme 2005.

Hybrid thin films containing palladium nanoparticles in different concentrations (0.5% and 1%) with and without nanoparticle stabiliser agent [mercaptopropyl trimethoxysilane, MPTMS] were prepared using a sol–gel process. Pd nanoparticles were found to be highly dispersed on the thin films with particles ranging from 7 to 10 nm. The catalytic properties of the thin films supported Pd nanoparticles were investigated in the Heck reaction of iodobenzene and methyl acrylate. Films containing Pd MNP (with and without MPTMS) gave quantitative conversion and complete selectivity to the targeted product (methyl cinnamate) in a short time of reaction (

A commercial vinylester-urethane (VEUH) hybrid resin was modified with organophilic layered silicates (OLS), incorporated in various amounts (0.1 to 5 wt.%). As organophilic intercalants of the layered silicate (synthetic fluorohectorite) trimethyl dodecylamine (TMDA) and octadecylamine - N,N-bis[allyl(2-hydroxypropyl)ether] (OAE) served. The latter quaternary amine was expected to support the intercalation/exfoliation of the silicate by participating in the crosslinking reactions. Both OLS types became intercalated based on X-ray diffractograms (XRD). Dynamic-mechanical thermal analysis (DMTA) displayed a slight increase in the stiffness by adding OLS up to 2.5 wt.%. However, at 5wt% OLS content the stiffness of the nanocomposites was below that of the unfilled hybrid resin. The glass transition temperature (Tg) did not change practically with the OLS type and content. Fracture mechanical tests were performed on compact tension (CT) specimens. The fracture toughness (Kc) increased slightly, while the fracture energy (Gc) markedly with increasing OLS content. Unexpectedly, TMDA proved to be a more suitable intercalant than OAE. The failure mode of the specimens was studied in a scanning electron microscope (SEM) and discussed. In addition, the water sorption behavior of the OLS modified VEUHs was determined and the diffusion coefficients (D) deduced.

We synthesized hybrid materials by sol-gel process, using: methyltriethoxysilane, tetraetylorthosilicate and vinyltriethoxysilane, in the presence of Rhodamine 6G. It was synthesized as well organic-inorganic hybrids with addition of tetraisopropyl orthotitanate and maleic anhydride UV-VIS spectra of dye show two absorption peaks at 499 nm (dimer) and 530 nm (monomer). Evaluating FTIR spectra of hybrid films, it was observed a band at 1077 cm−1, characteristic of the asymmetric Si-O-Si stretching vibration in oligomer. Fluorescence spectra show that tetraisopropyl orthotitanate presence in the composites modifies the nature of the inorganic matrix and affects the interaction with the added dye.

It was studied the polymerization of styrene (St) and of butyl acrylate (BuA) in nonionic microemulsions in the presence of a layered alumino silicates, montmorilonit (MMT) type. In time, the latexes separate in two distinct strata, MMT being distributed in the inferior strata where forms aggregates with on order of size bigger than the diameters of nanoparticles of latex. The solid products obtained are nanohybrids of intercalate type whose structural order increases direct proportional with the increase of hydrophobic character of the quaternary ammonium salts used for organophilization of MMT. The presence of nonionic surfactant, nonyl phenol with 25 mols of ethylene oxide, intercalated between the lamellar strata of MMT produces the decrease of thermal stability of hybrids and decreases the glass transition temperature of PSt which is more compatible than PBuA.

We have synthesized polymer particles of the type alternated copolymers DVB- maleic anhydride. The dimensions of the obtained particles have been determined by electron microscopy and are in the range 1–2 μm. These particles have been mixed by stirring and ultrasound with nematic liquid crystals ZLI 1221 (Merck), in a concentration of 5% b.w.(polymer/LC). We applied cycles of temperature and electric field, corresponding to the TSDC method. We measured the depolarization currents and simultaneously the optical transmission as a function of the electric field and temperature. We obtained information regarding the conduction mechanism, the activation energy and the pre-exponential frequency factor in the Arrhenius diagrams. The dipolar current obtained is consequent to a superposition of a dipolar distribution with a wide spectrum of relaxation times.

The work presents some preliminary results obtained in the attempt to perform hybrid polymer-based nanocomposites with laser synthesized carbon nanostructures and layered silicate. The preliminary results suggest that there is a close relation between the improved characteristics of the obtained nanocomposite and filler's properties. Laser synthesized nanocarbons, from almost amorphous up to fullerenic-like structure were used. As layered silicate, a modified Cloisite-type montmorillonite is mentioned. Preliminary results suggest that some of these addition agents lead to samples of nanocomposites with significant improvement of their aimed properties.

Carbon nanostructures with different morphologies to be used as reinforcing agent in hybrid polymer–carbon nanocomposites were prepared by CO 2 laser pyrolysis of a hydrocarbon-based mixture. Investigations on the epoxy-resin/nanocarbon composites have shown that their properties depend on the morphology of the nanopowders. Preliminary results suggest that some of these carbon nanopowders lead to samples of nanocomposites with significant improvement of their mechanical properties.

New hybrid materials based on polyether polyols were prepared by using a sol-gel reaction of alkyltriethoxysilanes, in the presence of propylenoxide-ethylenoxide trifunctional block copolymers. The resulting composites are transparent and have a filmogene behavior. Two types of filler systems were used: one based on silane precursors and one based on both the silane precursors and nanoclay (sodium montmorillonite). FT-IR spectra were evaluated to prove both the covalent interaction at the functional groups level and the presence of silica nanodomains formed by sol-gel process. The polarity changes were analyzed in the UV spectra, which shift according to the nature of different cationic dyes. Polyether hybrids were also obtained in the presence of some layered silicates. The X-ray diffraction reflects the changes in basal spacing of the Cloisite Na+, when it is added to different formulations. The modification of film morphology, depending on the reactants nature, can be observed in the SEM images.

Hybrid materials containing poly(vinyl acetate) and montmorillonite (MMT) were prepared using an one-batch emulsion polymerization recipe, assisted by a nonionic surfactant. To explain the results of our experiments, a thorough investigation of the specific interactions between the compounds was done, in the wet as well as the dried state of the end-products. In dispersion, polymer–surfactant interactions were found to be driven by hydrophobic coupling into superficial (mixt) admicelles. Another important finding is that the amount of clay used in the recipes and its relative concentration with respect to the other reaction partners influences drastically the morphological units in the end-products. For low [MMT], well-defined, spherical particles are formed. At the other extreme, for high [MMT], production of polymeric, water-swollen aggregates is favored. A small amount of reformed MMT tactoids was detected in all casted hybrid films, indicating that most of the inorganic is dispersed in the organic phase.

Polymer composites with cellulose microfibrils are materials with unique properties compared to existing materials: high strength, formability, and geometrical complexity at very small scale, low density, and abrasivity, biomedical compatibility, and possibility of recycling. Polymer composites from polypropylene and two types of cellulose microfibrils were prepared and characterized. To enhance the compatibility of cellulose microfibrils with polypropylene matrix, a silane-coupling agent and a modified polypropylene were used. Depending on the applied method, composite materials with enhanced mechanical properties were obtained. Morphostructural properties of cellulose microfibrils and polymer composites with treated and untreated microfibrils were investigated using scanning electronic microscopy (SEM), FTIR spectroscopy, and differential scanning calorimetry (DSC).

A series of aminopropyl-functionalized silica nanoparticles were prepared through a basic two step sol-gel process in water. Prior to being aminopropyl-functionalized, silica particles with an average diameter of 549 nm were prepared from tetraethyl orthosilicate (TEOS), using a Stöber method. In a second step, aminopropyl-silica particles were prepared by silanization with 3-aminopropyltriethoxysilane (APTES), added drop by drop to the sol-gel mixture. The synthesized amino-functionalized silica particles are intended to be used as supports for immobilization of humic acids (HA), through electrostatic bonds. Furthermore, by inserting beside APTES, unhydrolysable mono-, di- or trifunctional alkylsilanes (methyltriethoxy silane (MeTES), trimethylethoxysilane (Me3ES), diethoxydimethylsilane (Me2DES) and 1,2-bis(triethoxysilyl)ethane (BETES)) onto silica particles surface, the spacing of the free amino groups was intended in order to facilitate their interaction with HA large molecules. Two sorts of HA were used for evaluating the immobilization capacity of the novel aminosilane supports. The results proved the efficient functionalization of silica nanoparticles with amino groups and showed that the immobilization of the two tested types of humic acid substances was well achieved for all the TEOS/APTES = 20/1 (molar ratio) silica hybrids having or not having the amino functions spaced by alkyl groups. It was shown that the density of aminopropyl functions is low enough at this low APTES fraction and do not require a further spacing by alkyl groups. Moreover, all the hybrids having negative zeta potential values exhibited low interaction with HA molecules.

Organic–inorganic hybrid films were prepared based on a recipe using organoalkoxysilanes’ ability to create an inorganic network combined with polymer network formation via radical polymerization of the organic groups. The starting mixtures included different triethoxysilanes (RTES), where the organic substitute (R) was varied from methyl- (MeTES), phenyl- (PTES), octyl- (OTES) to vinyl- (VTES). Additionally, films prepared using methacryloxypropyltrimethoxysilane (MPTS) were also investigated. Most of the formulations were enriched with tetraisopropyl orthotitanate (TIP). Based on phase diagrams, the limits of the one-phase liquid regions were determined for the initial (RTES–ethanol–water) ternary mixtures. Non-linear modifications of the refractive indexes versus water concentration, as well as the measured conductivity changes indicate that these apparent homogeneous systems are nanostructured as microemulsions. Based on the results of combined microscale (atomic force microscopy (AFM)) and macroscale (wettability, thermal analysis) investigations, it was possible to observe the internal structure and to explain the measured properties of the final composite films. The high resistance against solvent attack is based on the regular, granular-like structure of the end products. Heating the films (at temperatures above the thermal degradation range for the incorporated organics) forces the inorganic structures to collapse and undergo phase transformations.

Free radical miniemulsion polymerization of styrene (St), St/acrylonitrile 3 : 1 mixture or methylmethacrylate in the presence of multiwalled carbon nanotubes (MWCNT) was proven as a convenient way to obtain homogenous hybrids with perspectives in associated applications like foams specialties materials. Miniemulsion polymerization was viable up to 2% wt. MWCNT to monomer, without agglomerations. The grafting on MWCNT during the polymerization occurs without the need for supplementary functionalization and the polymer grafted nanotubes showed stable dispersions in the polymer solvent. Monomer polarity affected the grafting ability during the polymerization process. The nanocomposites obtained after purification and drying were used in foaming process. MWCNT presence in the related nanocomposites decreased the pore sizes in foam-like materials (for all three different matrices). At 1 wt % MWCNT content, low density ( 109 cell/cm3) were achieved. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41148.

Composition domains corresponding to “one phase microemulsions” have been studied for the monomer mixtures consisting in vinyl acetate (VAc)–2-ethyl-hexyl acrylate (EHA) and VAc–ethyl acrylate (EtA). Maleic monoester with nonyl phenol ethoxylated with 25 mol ethylene oxide has been used as surfactant; n-propanol (n-PrOH), t-butanol (t-BuOH) and 2-ethyl-hexanol have been employed as cosurfactants. The number of microemulsions formed in the frame of the existing systems (as shown in ternary diagrams) is higher for polar monomers and cosurfactants: EtA>EHA; n-PrOH>t-BuOH. Refractometric and conductometric studies have proved the reality of three types of microemulsions: O/W, bicontinuous and W/O respectively. The homogeneous domains lessen after radical copolymerization. However, for the zone with a bicontinuous microstructure the conversion for the comonomer mixture reaches a minimum; a degradative chain transfer of the growing radicals with the cosurfactant might explain this phenomenon. It has been proved by GPC, that the concentration of unreacted surfactant increases when the concentration of the acrylic monomer increases as well.

In the present work the sol-gel process in the ternary system VAc-VTES-TEOS was approached. The monomer that ensures the crosslinking of the obtained networks is VTES, which could react with VAc by free-radical polymerisation and with TEOS by hydrolysis-polycondensation. The early stage evolution of the process was monitored by gas chromatography coupled with mass spectrometry (GC-MS). The gels obtained were characterised by IR spectroscopy, DTA/TG analysis and DSC measurements. Important differences in the gelling process and in the properties of the obtained gels could be noticed, related to the presence of VAc and VTES in the reaction mixtures. The investigation allowed to establish the compositions and the experimental conditions in which gels with high degree of crosslinking could be obtained.

The modification of decomposition rate of the potassium persulfate initiator during the synthesis of “two-stage latexes” polystyrene-ethyl acrylate (EtA) of butyl acrylale (BuA) and of 2-ethylhexyl acrylate (EHA) is studied. This rate is minimum for BuA and maximum for EHA, in good agreement with the value of solubility parameters. The appearance of poryacrvlaf.es determines the existence of water bonded to the polar polymer. The amount of water bonded increases in the sequence PEtA⩽PBuA⩽PEHA, function of the modification of the diameters of the particles resulted from the latexes obtained.

Ternary diagrams for the methyl methacrylate (MMA) (methanol (MeOH)/water and tetraethoxysilane (TEOS)/MeOH/water systems were studied. The composition domains, where microemulsions form owing to the nanostructures developed by the MeOH–water system, were determined. Refractometric and conductometric studies showed that water-in-oil (w/o), bicontinuous or oil-in-water )(o/w) microemulsions may form. Hybrid materials were obtained by the sol–gel reaction of TEOS combined with the free-radical copolymerization of MMA and methacryloxypropyltrimethoxysilane (MPS). MPS was added in order to avoid phase separation. The change of the glass transition temperature and of the thermal stability of the organic network in the presence of the inorganic one, and the similar forming mechanisms and rates proved the formation of simultaneous interpenetrating polymer-inorganic networks.

Polyacrylonitrile (PAN) and poly(acrylonitrile-co-vinylcarbazole) (PAN-VK) hybrids were obtained in presence of multiwalled carbon nanotubes (MWCNT) by a one-step free radical polymerization in miniemulsions. MWCNTs, in an unmodified state, as well as MWCNTs functionalized with maleic anhydride or monoethoxy dimethylvinyl silane, were used. The presence of MWCNT increased the molecular weights of the polymers and affected the polydispersity index. The polymers obtained next to the MWCNT showed a high value in their crystallinity index (33 %). The method was proven as an efficient route for dispersing nanotubes in the polymer matrix. Functionalized MWCNTs restrict the transfer reaction to areas next to the walls of the nanotubes during the polymerization and increase the dispersability in the final polymer matrix. MWCNT –polymer hybrids showed perspectives in membrane fabrication, as well as a specific profile, for carbon fibers precursors (with advantages in the three main stages: cyclization, dehydrogenation and decomposition).

Highly selective gallic acid imprinted polymers were synthesized by a suspension polymerization technique. Poly (hydroxyethyl methacrylate-co-ethyleneglycol dimethacrylate) and poly (dimethoxystyrene-co-divinylbenzene) beads were studied for gallic acid separation from green tea leaves. Isothermal binding was explained using Langmuir and Freundlich models. Recovery of gallic acid molecules was significantly improved up to 83 % when water was used as extraction solvent. Competitive adsorption, from a green tea leaves alcoholic extract, revealed higher affinities of imprinted polymers for gallic acid. An 18.8 selectivity coefficient was obtained for poly (hydroxyethyl methacrylate-co-ethyleneglycol dimethacrylate) imprinted beads. The performances of the imprinted polymers were in agreement with morphology and nitrogen adsorption analyses.