Synthesis and structural reactivity of inorganic–organic hybrid nanocomposites – A review

Chemistry of hybrid nanocomposites depends mainly on their reactivity and structural relationship. This review mainly reports on the processing techniques of inorganic–organic hybrid nanocomposites and their natural reactivity. Herein, the structure, processing methods and properties of nanocomposites with three different types of matrices are discussed in general. The perusal of this review enables the researchers to design a novel and simple route in processing the hybrid nanocomposites.     

Polyhedral oligomeric silsesquioxane (POSS) reinforced-unsaturated polyester hybrid nanocomposites: Thermal,thermomechanical and morphological properties

Unsaturated polyester (UP)-POSS hybrid nanocomposites have been developed successfully through the reaction between maleimide groups Octa (maleimido phenyl) silsesquioxane (OMPS) and olefinic reactive sites (maleimide and styrenic units) present in the unsaturated polyester resin system through free radical polymerization using benzoyl peroxide (BP) as the initiator. The hybrid molecular structure of nanocomposites resulted was evaluated by FT-IR spectroscopy. The data obtained from XRD, SEM and TEM analysis ascertain the presence of homogeneous morphology and nanoscale dispersion of OMPS into the polyester hybrid nanocomposites. Data resulted from thermal (DSC and TGA) and thermo-mechanical (DMA) studies indicated that the incorporation of octamaleimide functionalized POSS into unsaturated polyester systems appreciably improved the thermal properties of the hybrid nanocomposites according to their percentage concentration.     

Redox‐Active Hybrid Polyoxometalate‐Stabilised Gold Nanoparticles

We report the design and preparation of multifunctional hybrid nanomaterials through the stabilization of gold nanoparticles with thiol‐functionalised hybrid organic–inorganic polyoxometalates (POMs). The covalent attachment of the hybrid POM forms new nanocomposites that are stable at temperatures and pH values which destroy analogous electrostatically functionalised nanocomposites. Photoelectrochemical analysis revealed the unique photochemical and redox properties of these systems.     

Mechanical and anti‐stabbing properties of modified thermoplastic polymers impregnated multiaxial p‐aramid fabrics

New forms of hybrid multiaxial nanocomposites with enhanced mechanical and stab resisting properties are presented. This study is motivated by the lack of knowledge in the study of the multiaxial fabric nanocomposites with two modified thermoplastic matrices for antiballistic protection. Introduction of 5 wt.% silica nanoparticles in the composite of polyurethane/p‐aramid/poly (vinyl butyral) leads to significant improvement in mechanical properties, and the addition of silane as a coupling agents and glutaraldehyde as a crosslinking agents yielded maximal values of storage modulus, tensile modulus and anti‐stabbing properties for hybrid nanocomposites. Ballistic resistance testing and penetration depth of the hybrid nanocomposites were visualized using image analysis. Copyright © 2013 John Wiley & Sons, Ltd.     

Polypropylene wax (PPw)/silica hybrid by in situ non-aqueous sol–gel process for preparation of PP/silica nanocomposites

This paper presented a novel approach to prepare PP/silica nanocomposites. First, PPw-g-KH570 (γ-methacryloxypropyl trimethoxysilane) was obtained by pre-irradiation grafting method and characterized by FTIR and TGA. Then the non-aqueous sol–gel gelation kinetics of TEOS (tetraethoxysilane)-formic acid system in xylene was researched. Subsequently PPw/silica hybrid was obtained by in situ non-aqueous sol–gel reaction of TEOS in the presence of PPw-g-KH570 solution in xylene. Finally PP/silica nanocomposites were prepared by blending of PP matrix and PPw/silica hybrid. The mechanism of in situ formed PPw/silica hybrid was proposed. The morphology of PPw/silica hybrid and microstructures of PP/silica nanocomposites were characterized by TEM and SEM. The mechanical and thermal properties of PP/silica nanocomposites were also well studied by tensile tests and DSC. It was showed that the nanosilica particles were well dispersed in PPw/silica hybrid with the aid of grafting KH570 due to co-condensation by grafted KH570 and TEOS. PPw/silica hybrid was well dispersed in PP matrix with good compatibility and strong interactions. The resulted PP/silica nanocomposites possessed better performance than that of pure PP matrix.     

Direct Anisotropic Growth of CdS Nanocrystals in Thermotropic Liquid Crystal Templates for Heterojunction Optoelectronics

The direct growth of CdS nanocrystals in functional solid‐state thermotropic liquid crystal (LC) small molecules and a conjugated LC polymer by in situ thermal decomposition of a single‐source cadmium xanthate precursor to fabricate LC/CdS hybrid nanocomposites is described. The influence of thermal annealing temperature of the LC/CdS precursors upon the nanomorphology, photophysics, and optoelectronic properties of the LC/CdS nanocomposites is systematically studied. Steady‐state PL and ultrafast emission dynamics studies show that the charge‐transfer rates are strongly dependent on the thermal annealing temperature. Notably, annealing at liquid‐crystal state temperature promotes a more organized nanomorphology of the LC/CdS nanocomposites with improved photophysics and optoelectronic properties. The results confirm that thermotropic LCs can be ideal candidates as organization templates for the control of organic/inorganic hybrid nanocomposites at the nanoscale level. The results also demonstrate that in situ growth of semiconducting nanocrystals in thermotropic LCs is a versatile route to hybrid organic/inorganic nanocomposites and optoelectronic devices.     

Enhancing dielectric and mechanical behaviors of hybrid polymer nanocomposites based on polystyrene,polyaniline and carbon nanotubes coated with polyaniline

The dielectric and mechanical properties of hybrid polymer nanocomposites of polystyrene/polyaniline/carbon nanotubes coated with polyaniline(PCNTs) have been investigated using impedance analyzer and extensometer. The blends of PS/PANI formed the heterogeneous phase separated morphology in which PCNTs are dispersed uniformly. The incorporation of a small amount of PCNTs into the blend of PS/PANI has remarkably increased the dielectric properties. Similarly, the AC conductivity of PS/PANI is also increased five orders of magnitude from 1.6 × 10~(-10) to 2.0 × 10~(-5) S·cm~(-1) in the hybrid nanocomposites. Such behavior of hybrid nanocomposites is owing to the interfacial polarization occurring due to the presence of multicomponent domains with varying conductivity character of the phases from insulative PS to poor conductor PANI to highly conductive CNTs. Meanwhile, the tensile modulus and tensile strength are also enhanced significantly up to 55% and 160%, respectively, without much loss of ductility for three phase hybrid nanocomposites as compared to the neat PS. Thereby, the hybrid nanocomposites of PS/PANI/_P CNTs become stiffer, stronger and tougher as compared to the neat systems.     

漆酚钛聚合物/蒙脱土纳米复合材料的制备、结构与性能

用溶液插层聚合方法制备漆酚钛聚合物/蒙脱土纳米复合材料(PUTi/OMMT),并用XRD、TEM和TG等对其结构、性能进行测试与表征.XRD结果表明,通过溶液插层,PUTi分子链进入了OMMT片层间,从而使片层间距增大.TEM观察表明OMMT片层在PUTi聚合物中基本达到纳米级分散.与PUTi相比,PUTi/OMMT纳米复合材料具有更好的耐热性能和抗紫外光性能.     

Study on the Zn(II)-Doped CdS Luminescent Nanoparticles Formation on the Chelating Polymer Microsphere

Highly photoluminescent hybrid Zn(II)-doped CdS nanocluster/copolymer nanocomposites latex were prepared by using the chelating copolymer, poly(methyl methacrylate-co-methyl acrylate-co-2-methyl acrylic acid 3-(bis-carboxymethyl amino)-2-hydroxyl-propyl ester), with in-situ chemical precipitation method. The morphology and photoluminescence property of the hybrid Zn(II)-doped CdS nanocluster/copolymer nanocomposites latex was examined by TEM and photoluminescence analyzer (PL), respectively. The photoluminescent intensity of the hybrid CdS nanocluster/copolymer nanocomposites could be enhanced by Zn(II) doped treatment from the PL measurement. Furthermore, these hybrid nanocomposite latex could be easily manufactured into the transparent nanocomposite membrane without losing their photoluminescence property as they were cured at 60 °C. Interestingly, the photoluminescence property of the hybrid Zn(II)-doped CdS nanocluster/copolymer nanocomposite membranes would be influenced by amino compounds due to the surface passivation effect. When the secondary amine compounds were used as the surface passivation materials, the photoluminescent intensity of the hybrid nanocomposite membrane would be enhanced. On the contrary, the hybrid nanocomposite membranes would descend their photoluminescent intensity as the primary amine compounds were used as surface passivation materials.     

Polyaniline‐Intercalated Molybdenum Oxide Nanocomposites: Simultaneous Synthesis and their Enhanced Application for Supercapacitor

A new and universal synthetic strategy to hybridize metal oxides and conduct polymer nanocomposites has been proposed in this work. The simultaneous reaction process, which includes the generation of metal oxide layers, the oxidation polymerization of monomers, and the in situ formation of polymer–metal oxides sandwich structure is successfully realized and results in the unique hybrid polyaniline (PANI)‐intercalated molybdenum oxide nanocomposites. The peroxomolybdate proved to play a dual role as the precursor of the inorganic hosts and the oxidizing agent for polymerization. The as‐obtained hybrid nanocomposites present a flexible lamellar structure by oriented assembly of conductive PANI chains in the MoO₃ interlayer, and thus inherit excellent electrical performance and possess the potential of active electrode materials for electrochemical energy storage. Such uniform lamellar structure together with the anticipated high conductivity of the hybrid PANI/MoO₃ nanocomposites afford high specific capacitance and good stability during the charge–discharge cycling for supercapacitor application.     

Gold and iron oxide hybrid nanocomposite materials

This critical review provides an overview of current research activities that focused on the synthesis and application of multi-functional gold and iron oxide (Au-Fe(x)O(y)) hybrid nanoparticles and nanocomposites. An introduction of synthetic strategies that have been developed for generating Au-Fe(x)O(y) nanocomposites with different nanostructures is presented. Surface functionalisation and bioconjugation of these hybrid nanoparticles and nanocomposites are also reviewed. A variety of applications such as theranostics, gene delivery, biosensing, cell sorting, bio-separation, and catalysis is discussed and highlighted. Finally, future trends and perspectives of these sophisticated nanocomposites are outlined. Underpinning the fundamental requirements for effectively forming Au-Fe(x)O(y) hybrid nanocomposite materials would shed light on future development of nanotheranostics, nanomedicines, and chemical technologies. It would be interesting to investigate such multi-component composite nanomaterials with different novel morphologies in the near future to advance chemistry, biology, medicine, and engineering multi-disciplinary research (120 references).     

Toughening of Polymer-layered Silicate Nanocomposites

The field of organic-inorganic nanocomposites has recently attracted consideration attention due to their unexpected hybrid properties synergistically resulting from their parent components. One of the most promising organic-inorganic nanocomposites is polymer-layered silicate (PLS) nanocomposites. Some PLS nanocomposites exhibite dramatic increase in mechanical properties as well as gas barrier properties. But one pervasive problem with nylon-6 and epoxy nanocomposites for applications is their low fracture toughness. The objective of this research is to a method of toughening the nylon-6 and epoxy-silicate nanocmposites in order to have the proper toughness/stiffness balance of such nanocomposites.     

Polymer Sol-Gel Synthesis of Hybrid Nanocomposites

The current state and main problems of polymer sol-gel synthesis as a method of the preparation of hybrid polymer-inorganic nanocomposites are analyzed. The general characterization of sol-gel reactions is given and the routes of the combination of sol-gel synthesis with the polymerization of traditional monomers are considered. Particular attention is given to the formation of sol-gel precursors in the presence of organic polymers, including the formation of interpenetrating hybrid networks. The specificity of hybrid nanocomposites based on multicomponent ceramics is discussed. The sol-gel process is analyzed as a promising route for the preparation of bioceramics in the presence of templates.     

Octafunctional cubic silsesquioxane (CSSQ)/poly(methyl methacrylate) nanocomposites: Synthesis by atom transfer radical polymerization at mild conditions and the influence of CSSQ on nanocomposites

Organic/inorganic hybrid star‐like nanocomposites from two different octafunctional cubic silsesquioxane (CSSQ) nano‐cage cores and poly(methyl methacrylate) (PMMA) were synthesized using atom transfer radical polymerization (ATRP) at mild conditions, in which octafunctional octakis(3‐hydroxypropyldimethylsiloxy)octasilsesquioxane (OHPS) and octa(aminophenyl)silsesquioxane (OAPS) nano‐cages were used as ATRP initiators. The polymerization was carried out at 50 °C in acetonitrile/water mixture. ¹H‐NMR and GPC were employed to characterize the obtained nanocomposites. GPC data revealed that the resulting nanocomposites exhibit unimodal and narrow molecular weight distributions indicating well‐controlled synthesis and well‐defined hybrid nanocomposites with star architecture. The influence of CSSQ nano‐cages on the thermal property of nanocomposites was investigated using differential scanning calorimetry and thermal gravimetric analysis (TGA). It was observed that the nanocomposites exhibit significantly higher glass transition temperature compared with its linear counterpart because of slow relaxation caused by the star‐like architecture. TGA study, however, did not reveal any significant improvement in thermal stability of nanocomposites as compared with linear PMMA. Finally, field emission scanning electron microscopy images of fractured surfaces of nanocomposite sample films showed well dispersed CSSQ nano‐cages in PMMA matrix without phase separation. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 766–776, 2008     

A comprehensive study on the impact of RGO/MWCNT hybrid filler reinforced polychloroprene rubber multifunctional nanocomposites

Flexible dielectric chloroprene rubber (CR) nanocomposites reinforced by one-dimensional carbon nanotube (CNT)/two dimensional reduced graphene oxide hybrids have been prepared using two-roll mill mixing technique. Non-covalent π-π interaction between multiwalled carbon nanotubes (MWCNTs) and reduced graphene oxide (RGO) nanosheets and the secondary interaction between fillers and chloroprene rubber matrix are responsible for generating the effective load transfer between RGO/MWCNTs and CR. The prepared RGO-MWCNT hybrid nanocomposites with high dielectric constant (≈650), low dielectric loss (≈0.42) and high energy storage efficiency (78.6%) values are practically good enough to use as a low cost polymeric dielectric layer in transistors. Furthermore, the prepared nanocomposites showed excellent electromagnetic effectiveness; a maximum shielding efficiency of 11.87 dB @ 3.5 GHz was achieved at 4 phr of MWCNT loading. This excellent electromechanical performance can be ascribed to the synergistic effect of RGO-MWCNT hybrid suggesting that this novel hybrid nanocomposite serves as an attractive candidate in modern electronics and electric power systems.     

Dispersion of silica nano-particles in sol-gel hybrid resins for fabrication of multi-scale hybrid nanocomposite

Multi-scale hybrid nanocomposites containing both ∼15 nm silica colloids and ∼2 nm oligosiloxanes in a methacryl polymer matrix were newly designed and fabricated. Colloidal silica sols were dispersed in methacryl oligosiloxanes nano-hybrid resins synthesized by sol-gel reaction of methacryloxypropylmethoxysilane and diphenylsilanediol. On the basis of TEM and SANS analyses, it was confirmed that the silica colloids were compatibly dispersed and different sizes of colloidal silica and oligosiloxanes co-exist in the solutions. Multi-scale hybrid nanocomposites fabricated by UV and thermal curing with incorporation of silica colloids in the nano-hybrid materials show enhanced mechanical and thermal characteristics.     

Poly(methyl methacrylate)/Methacryl-POSS Nanocomposites with Excellent Thermal Properties

Poly(methyl methacrylate) (PMMA) nanocomposites containing (methacryloxy)propyl polyhedral oligomeric silsesquioxane (methacryl‐POSS) were prepared by bulk‐polymerization process. The structures of the products were characterized by FTIR, solid‐state NMR, TEM, XRD, DSC, TGA, XPS and UV‐Vis spectra. The hybrid materials were found to be largely homogeneous. DSC and TGA results indicate that the thermal properties of PMMA nanocomposites are significantly improved. The glass transition temperature (T_g) and thermal decomposition temperature (T_dec) of the nanocomposites increased by 58 and 110°C, respectively. The bulk hybrid material maintains excellent optical transparency in visible region.     

Photophysical Characteristics of Multicolor Emitting MDMO-PPV–DMP/ZnO Hybrid Nanocomposites

The tuning of photophysical properties of the poly[2-methoxy-5-(3,7-dimethyl-octyloxy)-1,4-phenylenevinylene]—end capped with dimethylphenyl (DMP), MDMO-PPV–DMP, was achieved by incorporation of ZnO NPs with various contents. Hybrid nanocomposites of MDMO-PPV–DMP with ZnO NPs were prepared by solution blending method and then deposited onto glass substrates. The structural properties of the hybrid nanocomposites samples were characterized using X-ray diffraction, FTIR, and FE-SEM, while their optical properties were extracted from the absorption and photoluminescence spectra. The energy band gap, energy tail, steepness parameter, and CIE chromatic coordinates were tuned by increase the content of ZnO NPs into the polymer matrix. The ZnO NPs incorporation assists the emission wavelength shift and multicolor emitting from the hybrid nanocomposites.     

Polybenzoxazine–silica (PBZ–SiO2) hybrid nanocomposites through in situ sol–gel method

New type of Polybenzoxazine–silica (PBZ–SiO₂) hybrid nanocomposites was prepared through in situ sol–gel method. Benzoxazine was synthesized using bisphenol-A, trans-4-aminocyclohexanol hydrochloride and formaldehyde solution through Mannich condensation reaction and was characterized by FT-IR, ¹HNMR and ¹³CNMR spectroscopy. The methodology adopted in the present study involves to formation of hydrogen bond interaction between the benzoxazine monomer and the silica matrix, followed by the ring opening polymerization of benzoxazine monomer through thermal curing to obtain a red brown transparent PBZ–SiO₂ hybrid. The formation of hybrid nanocomposites was confirmed by FT-IR. Thermal and morphological properties of the hybrid materials were investigated by the differential scanning calorimetry (DSC), thermo gravimetric analysis (TGA), scanning electron microscopy (SEM). The PBZ–SiO₂ hybrids show improved thermal properties and glass transition (Tg) temperature. The nitrogen porosimetry study was carried out to confirm the nanometer level integration of polybenzoxazine in the PBZ–SiO₂ hybrid nanocomposites.     

乳液聚合法制备聚苯乙烯/Mg-Al层状双氢氧化物纳米复合材料

采用乳液聚合法制备阻燃性聚苯乙烯MgAl层状双氢氧化物(LDHs)纳米复合材料.通过对不同合成条件下复合材料的XRD谱,讨论了纳米复合材料的形成过程;经SEM图证实了LDHs是以剥离的纳米级层片分散在基体中的;TG和DSC谱图揭示了LDHs纳米层板可有效提高PS的热稳定性,并可使PS的玻璃化转化温度明显提高;当层状双氢氧化物在插层复合材料中含量为14.92%时,纳米复合材料的氧指数可达23.5%,其用量比在PS中直接添加纳米LDHs时要少约一倍.文中还分析了纳米复合材料的形成过程.