Synthesis Of Polymer Nanocomposites Research Articles

Erratum to: Successive Modification of Montmorillonite with Quaternary Alkylammonium Salts of Various Structures as a Method of Preparing Nanofillers for in situ Synthesis of Polymer Nanocomposites (SILAR)-Deposited CuO Thin Films of Nitrobenzene

Erratum to: Successive Modification of Montmorillonite with Quaternary Alkylammonium Salts of Various Structures as a Method of Preparing Nanofillers for in situ Synthesis of Polymer Nanocomposites (SILAR)-Deposited CuO Thin Films of Nitrobenzene

Successive Modification of Montmorillonite with Quaternary Alkylammonium Salts of Various Structures as a Method of Preparing Nanofillers for in situ Synthesis of Polymer Nanocomposites

Successive Modification of Montmorillonite with Quaternary Alkylammonium Salts of Various Structures as a Method of Preparing Nanofillers for in situ Synthesis of Polymer Nanocomposites

Tuning of TiO2 nanoparticles incorporation in poly methyl methacrylate for synthesis of polymer nanocomposites for promising biomedical application

Polymer Nano-Composites (PNC) exhibit advanced applications that depend on the surface characteristics and physicochemical properties of materials. These physical and physicochemical properties of materials can be modified for the use of nanomaterials as fillers in a polymer matrix with some appropriate mixing or incorporation. Hence, it is a critical and crucial task to identify the apt amount of the filler that is suitable for most of the applications. Hence, to identify the apt amount that is suitable for various applications, we had synthesized the PNC using TiO2 Nano-Particles (NPs) as filler in various amounts in Poly-methyl-methacrylate (PMMA). As synthesized PNC was characterized for their optical, surface and electrical properties. The results are compared in such a manner to find out the apt amount of TiO2, which can give the best performance as PNC for various applications. The study illustrates that less than 2% of TiO2 incorporation is insufficient as the total surface contact is very less that is not suitable for most of the applications. While for the incorporation of more than 5% of TiO2 NPs, particles get start to agglomerate during the synthesis of PNC that limits the applications of PNC that is generated due to nano-phase of the material. The focused aim of this study is to enhance the properties of polymers in such a manner that they can be used as biomaterials. Hence, we have also explored the wettability and bacterial response of the PNC. Here 3% − 4% incorporation of TiO2 NPs provides excellent results to PNC, so at these incorporation amounts of TiO2 in PMMA, this modified PNC can be used as a biomaterial. The technique explores the use of nanotechnology for the new class of PNC with modified properties.

The Frontal Polymerization Method in High Technology Applications

The method of frontal polymerization (FP) has been presented repeatedly in different publications but, taking into account the aim of this review, we intend to focus detailed and oriented attention on the process specificity that causes its unexpected advantages. This work has disclosed the ways to detect, reveal, and investigate the foundations of the frontal polymerization method and their use in different areas of science and technology. As researchers gain closer insight into this nontypical method of polymerization, they reveal new advantages and possibilities for its use to solve many problems both in the synthesis of polymer nanocomposites with retention of nanoscale dimensions, uniform distribution, and the optimal number of nanoparticles and in the synthesis of intercalated polymeric high-temperature superconductors, multifunctional gradient materials, hydrogels with prescribed properties, and other materials. It has been shown that the models and revealed features for the transition of linear autowaves into nonlinear ones are of interest and can be used similarly to the autowave processes that occur by the Belousov–Zhabotinsky mechanism in biology and human organism. With allowance for that noted above, this paper also describes the kinetic features of frontal polymerization that cause us to reconsider certain approaches and principles of formal kinetics. The ways and methods to pass from formal (isothermal) kinetics to nonisothermal kinetics (by the example of adiabatic polymerization) with finding the new principles of kinetic computations under nonisothermal conditions in application to frontal polymerization are given.

Development of biodegradable cellulose‐g‐poly(butyl acrylate)/kaolin nanocomposite with improved fire retardancy and mechanical properties

ABSTRACTThe main aim of the work is to convert a low cost renewable biopolymer to a high performance fire‐retardant biomaterial by modification via grafting. Cellulose, a linear and most abundant biomacromolecule, has gained increasing attention for its interesting properties and potential applications in the synthesis of polymer nanocomposites. Cellulose has been grafted with butyl acrylate via emulsifier free emulsion polymerization using in situ developed transition metal complex initiating system: CuSO4/glycine/ammonium persulfate with and without additive kaolin to prepare nanocomposites and copolymer, respectively. The morphology of so‐prepared grafted nanocomposites was characterized by Fourier transform infrared spectroscopy, X‐ray diffraction, and field emission scanning electron microscopy. The enhancement in thermal behavior and mechanical properties of nanocomposites over copolymer were outstanding. The fire‐retardant properties were evaluated by limiting oxygen index and cone calorimetry test. The biodegradation and water absorbency of the fire‐retardant nanocomposites have been carried out for better commercialization and environmental concern. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45968.

Poly(meth)acrylate nanocomposite membranes containing in situ exfoliated graphene platelets: Synthesis, characterization and gas barrier properties

Here we report a novel method for the preparation of polymer nanocomposites containing in situ exfoliated graphene nanoplatelets. First, graphite particles were modified by sodium and ethylenediamine (en), yielding first-stage graphite intercalation compounds (GICs) containing [Na(en)]+ complex between carbon sheets. After subsequent ion-exchange reaction of the intercalated complex with quaternary ammonium salt bearing methacrylamide group, GICs possessing polymerizable double bond were obtained. It was found that the extent of [Na(en)]+ complex intercalation as well as the ion-exchange reaction was significantly dependent on the type of the graphite used (natural vs. synthetic). GICs derived from natural graphite were further employed in the synthesis of polymer nanocomposites. Using NMR and TEM it was confirmed that the methacrylamide group in GICs participated successfully in the process of copolymerization with 2-hydroxyethyl methacrylate and 2-ethylhexyl acrylate, resulting in the in situ GICs exfoliation. The prepared nanocomposite membranes were further characterized using X-ray diffraction, DSC and TGA. Gas permeability measurements on the polymer composites were also carried out, confirming that the initial GIC was present in an exfoliated form.

Heterogeneous initiators for the synthesis of polymer nanocomposites

Nanocomposites are obtained by the radical polymerization of styrene and methyl methacrylate on the surface of a dispersed filler containing chemisorbed compounds of quaternary ammonium, which catalyze decomposition of cumene hydroperoxide. The heterogeneous catalysts of hydroperoxide decomposition are obtained via the adsorption of cetyltrimethyl ammonium bromide and acetylcholine chloride on sodium montmorillonite, cellulose, and chitosan. The highest rate of the polymerization of both monomers is provided by the cellulose–cetyltrimethyl ammonium bromide catalyst. For a more hydrophilic methyl methacrylate, the rate of radical initiation is significantly lower at the same concentrations of the catalyst and hydroperoxide compared with hydrophobic styrene; however, the rate of polymerization is higher than for styrene because of a higher activity of methyl methacrylate in chain-propagation reactions. Relatively high rates of radical generation upon contact of cellulose–cetyltrimethyl ammonium bromide and cellulose–acetylcholine with hydroperoxides open the possibility to create cellulose-based disinfecting and medical materials.

Synthesis of nanocomposite based on poly(lactic acid) and montmorillonite by in situ polycondensation

In the present work, a method of synthesis of polymer nanocomposite based on poly(lactic acid) and layered alumosilicate montmorillonite by in situ polycondensation is described. At reaction temperatures of 160–200°С and catalyst concentration from 0 up to 5 ppt, the samples of composite materials containing 0.5–3 wt % of montmorillonite were synthesized. The composite material is characterized by an exfoliated structure of alumosilicate and a complex of enhanced physicochemical properties.

A facile method to anchor reduced graphene oxide polymer nanocomposite on the glassy carbon surface and its application in the voltammetric estimation of tryptophan in presence of 5-hydroxytryptamine

A 4-amino-3-hydroxy-1-naphthalenesulfonic acid (AHNSA) and reduced graphene oxide (rGO) based polymer nanocomposite (PNC) has been electrodeposited directly on the surface of glassy carbon electrode (GCE) using cyclic voltammertry. The electrochemical reduction of graphene oxide (GO) to rGO and the synthesis of PNC have been inspected using FE-SEM, TEM and Raman spectroscopy. The modified GCE was further used for the voltammetric quantification of Tryptophan (Trp) in the presence and absence of 5-hydroxytryptamine. The PNC modified sensor exhibited improved sensing and electrocatalytic properties in comparison to unmodified GCE, rGO modified GCE and AHNSA modified GCE. The fabricated sensor showed a linear calibration plot in the range of 0.5–200μM with sensitivity and limit of detection (L.O.D.) of 0.0451μAμM−1 and 316nM (n=3) respectively in comparison to 0.19μAμM−1 and 2.54μM (n=3) respectively for unmodified GCE. The proposed method was also successfully applied for the determination of Trp in commercially available pharmaceutical formulations, human urine and plasma samples.

L-Phenylalanine edge functionalized graphite nanoplatelets as a nanoscale filler for poly(ester–amide–imide) matrix

The recent growth in studying graphene has proved the utilization of graphene as reinforcement filler in the synthesis of polymer nanocomposite. The potential application of graphene could be improved by covalent functionalization of graphene without any defects on the graphene basal plane through edge-selective functionalization process. To this aim, in this study graphite nanosheets were selectively functionalized at their edges with l-phenylalanine in a mild reaction medium. The prepared edge functionalized graphite (EFG) was used as nanoscale filler into optically active poly(ester–amide–imide) (PEAI). The structure and properties of EFG and PEAI/EFG nanocomposites were investigated and the effects of EFG on thermal and morphological properties of PEAI were examined.

Supercritical carbon dioxide-assisted process in synthesis of polymer/clay melt

Nanocomposites are currently being used in a number of fields, and new applications are continuously being developed including mechanical and biomaterial devices, as well as various in solar and fuel cells applications. Generally, the synthesis of polymer nanocomposites are done using solution chemistry, and this may raise serious concerns regarding air and water pollutions. Immediately, the ‘green’ method using supercritical carbon dioxide (scCO2) has grabbed the attention of researchers who are responsible to synthesize polymer composites by non-hazardous routes. Extrusion processes would benefit from the use of scCO2 since the rationale of the extrusion process is to formulate, provide texture and shape molten polymers by forcing them through a die. ScCO2 has been used in several studies as a medium of clay dispersion in polymer matrix by providing a solvent-free fabrication route for nanocomposites. Furthermore, it has more favorable interactions with polymers compared to other inert gases and has the ability to be dissolve in large quantities. It acts as a plasticizer, which modifies viscosity and interfacial properties of the polymer drastically. In this paper, experimental and theoretical studies of solubility and viscosity of several polymer melts in clay are discussed in detail. The assistance of scCO2 in clay dispersion and as a foaming agent has been reviewed extensively.

Sonochemical production and characterization of d-fructose functionalized MWCNTs/alanine-based poly(amide-imide) nanocomposites

This study presents the preparation of d-fructose covalently functionalized multiwalled carbon nanotube (MWCNT-Fr) and its application in the synthesis of polymer nanocomposites (NCs). Poly(amide-imide) (PAI) as matrix of NCs was synthesized from polycondensation reaction between N-trimellitylimido-l-alanine diacid and 4,4′-diamino diphenyl methane under green conditions. Different percents of functionalized multiwalled carbon nanotube (MWCNT-Fr) were dispersed in the PAI using a solution mixing technique. Increased outer diameter and rough surface of the MWCNT-Fr showed the coating of fructose on the surface of MWCNTs. X-ray diffraction analysis was performed in order to confirm the presence of MWCNT-Fr in the PAI matrix. Surface morphology examination showed that the MWCNT-Fr was very well dispersed in the PAI matrix. The thermal properties of the blends were also evaluated. Our results demonstrated according to the limited oxygen index values that these NCs could be classified as self-extinguishing materials.

Synthesis of SBA-16 Supported Catalyst for CNTs and Dispersion Study of CNTs in Polypyrrole Composite

ABSTRACTIn last two decades, huge amount of research work has been contributed in the field of nanochemistry particularly for synthesis, characterization and applications of carbon nanotubes (CNTs). For synthesis of CNTs through chemical vapor deposition (CVD), supported metal catalyst is used preferentially. In view of that, SBA-16 supported nanoprticles of Iron, Fe/SBA-16, were prepared. To have Fe/SBA-16, adsorption of Fe nanoparticles on SBA-16 have been accomplished by reduction of ferrous ion on the surface of SBA-16. Afterwards, CNTs were synthesized by CVD using benzene as precursor over Fe/SBA-16 nanocatalyst. Synthesis of CNTs was carried out at 750°C with ambient pressure. Synthesized CNTs were functionalized by treating the them with a mixture of H2SO4/HNO3. As a result of this acidic treatment, carboxylic functional group was introduced on the surface of CNTs due to oxidation. As such prepared and functionalized CNTs were, further, used as filler in the synthesis of polymer nanocomposites of polypyrrol(PPY), matrix. These nanocomposites were prepared by in situ polymerization. Thus, electrical conductivity is measured for both types of polymer composites. On their comparison, important information regarding dispersion of CNT in the matrix are extracted.

Light-Selective Nanofilms of Quantum Dot-Poly(ethylene-co-vinyl acetate) Synthesized with Supercritical CO2

The synthesis of polymer nanocomposites with incorporated quantum dots (QDs) has been attracting significant interest due to their unique applications in a variety of fields. Here we explored the synthesis and characterization of novel QD-poly(vinyl acetate) (PVAc) and poly(ethylene-co-vinyl acetate) (PEVA) nanocomposites for application as light-selective nanofilms. Both CdS and CdS-ZnS core−shell QDs were synthesized by means of pyrolysis of single molecular precursors at 180 °C, and then functionalized with a methoxysilane group for subsequent attachment to polymer chains by using sol−gel chemistry. These novel materials were examined with FTIR, EDX elemental analysis, solubility tests, photoluminescence, and UV−vis spectroscopy for characterization of the QDs, indicating successful synthesis and functionalization. The functionalized QDs were then used to synthesize novel QD-PVAc and QD-PEVA nanocomposites via a one-pot technique in supercritical carbon dioxide (scCO2), which acts as a solvent and drying agent for the sol−gel chemistry linking the QDs to the polymer chains. In the synthesis of QD-PVAc, the characteristic emission peak of the QDs was quenched attributed to phase separation in the nanocomposites. By stabilizing the QDs with an excessive amount of ligands and controlling the reaction conditions, light-selective QD-PEVA nanofilms were successfully synthesized by using a two-step technique in scCO2. The synthesized QD-PEVA nanofilms displayed significant absorption in the UV and violet regions of the electromagnetic spectrum, while providing a characteristic emission in the region from orange to red light. This novel synthesis route can be applied to the synthesis of other light-selective nanofilms by varying the quantum dot and polymer systems.

Dispersity and stability measurements of functionalized multiwalled carbon nanotubes in organic solvents

Multiwalled carbon nanotubes (MWCNTs) have attracted a great deal of attention due to their unique properties. However, due to interstrand van der Waals forces, their poor dispersity in aqueous or organic solvents has limited their practical applications. Chemical modification of their surfaces has been investigated in order to achieve good dispersity of MWCNTs in general and specifically regarding organic solvents. Because organic solvents are more suitable than water for processing various polymers, it is necessary for MWCNTs to be dispersed in organic solvents to allow the synthesis of polymer nanocomposites. To uniformly disperse MWCNTs in common organic solvents without the use of surfactants, acid treatment was carried out to introduce carboxyl groups, followed by alkylation with an alkyl halide to form alkylated MWCNTs. In this study, the effective dispersity of alkylated MWCNTs in acetone, toluene, and chloroform was observed by transmission electron microscopy. The dispersive stability of the MWCNTs over a period of 10 days was also investigated by using a Turbiscan optical analyzer.

Alternative Synthetic Routes to Epoxy Polymer – Clay Nanocomposites using Organic or Mixed‐Ion Clays Modified by Protonated Di/Triamines (Jeffamines)

AbstractThe use of homoionic organic clays and mixed‐ion organic/inorganic clays modified by di‐ or triamines (Jeffamines), which are being used as epoxy resin curing agents, in the synthesis of polymer nanocomposites has been studied in this work. Our aim is to enhance polymer crosslinking and interfacial adhesion in the nanocomposite structure by utilizing the functionality of the di/triamines on the surface of clay nanolayers and by reducing the organic modifier via formation of homostructured mixed‐ion organic/inorganic clays. The results show that the use of homoionic organic clays exchanged with relatively short chain di‐ or triamines and mixed‐ion organic/inorganic clays partially exchanged (ca. 35%) with long chain diamines resulted in intercalated structures with enhanced thermo‐mechanical properties (Young's Modulus, Storage Modulus). On the other hand, homoionic organic clays exchanged with long chain diamines and triamines resulted in exfoliated nanocomposites but with compromised mechanical properties due to the plasticizing effect of the long chain amine modifiers.

Organo-vermiculites: synthesis, structure and properties. Platelike nanoparticles with high aspect ratio

Organo-vermiculites with large d-spacing, advantageous for the synthesis of polymer nanocomposites, were prepared by exchanging the mineral inorganic cations for quaternary alkylammonium ions. The interlayer Mg2+ of the pristine vermiculite was exchanged by Na+ in advance to enhance the exchange with the organic cations. The organophylization of the mineral was monitored by determining its exchange capacity as well as the organic surface coverage. Alkylammonium ions with different chain length and number of chains attached to the nitrogen atom were exchanged and the properties of the organo-vermiculites investigated by infrared spectroscopy (IR), nuclear magnetic resonance spectroscopy (NMR), X-ray diffraction (XRD) and differential scanning calorimetry (DSC). Dioctadecyldimethylamonium–vermiculite showed a d-spacing as large as 3.9 nm. The alkylammonium ions self-assemble on the vermiculite surface, leading to an ordered two-dimensional lattice, in which the alkyl chains preferentially assume an all-trans conformation. On heating, conformational transformation of the alkyl chains gradually takes place resulting in a dynamically disordered phase. The transition from an ordered all-trans conformation to a dynamically disordered state manifests itself in IR-absorption and carbon resonance frequency shifts accompanied by an abrupt enthalpy change. The transition temperature and enthalpy depend on the alkyl chain length and packing density.

Synthesis of polymer nanocomposites by UV-curing of organoclay–acrylic resins

Nanocomposite materials made of silicate platelets dispersed in a crosslinked polymer have been produced by photoinitiated polymerization of a multifunctional acrylic resin containing organophilic clay. Exfoliation of the silicate nanoparticles was demonstrated by X-ray diffraction spectroscopy and by transmission electron microscopy. Under intense illumination, the solvent-free hybrid formulation was transformed within seconds into a hard and tough material at ambient temperature. The UV-curing reaction was followed by infrared spectroscopy (mid-IR, near-IR and ATR) through the decrease upon UV exposure of the characteristic IR bands of the acrylate double bond. The organoclay was found to have no detrimental effect on the photopolymerization reaction. The performance of the UV-cured polymer, microcomposite (clay) and nanocomposite (organoclay) samples were compared with respect to their tensile strength, break elongation, hardness and moisture resistance. Nanocomposites were found to outperform microcomposites in most of these properties. They proved particularly resistant to accelerated weathering in the presence of adequate light-stabilizers.

Structure and Properties of Alkylammonium Monolayers Self-Assembled on Montmorillonite Platelets

Monolayers of mono-, di-, tri-, and tetraalkylammonium cations of varying chain length (C4, C8, and C18) were self-assembled on montmorillonite platelets. The structure and chain dynamics of these SAMs were probed by infrared spectroscopy (IR), nuclear magnetic resonance spectroscopy (NMR), X-ray diffraction (XRD), and differential scanning calorimetry (DSC). Depending on the cross-sectional area, the available area/cation, and the alkyl chain length, the molecules adopt a two-dimensional order or a disordered state at ambient temperatures. Short alkyl chains lie flat, disordered on the substrate surface as long as there is enough space. With increasing volume of the organic layer between two silicate layers facing each other, the chains force the layers to enlarge their basal-plane spacing but remain disordered. At a certain length and number of chains, the molecules adopt an ordered state due to increasing chain interactions and packing density. To minimize their conformational entropy and maximize their packing density, the chains attached to platelets facing each other interdigitate. The average molecular axis in the organic thin film is inclined to the montmorillonite surface normal by an angle, which depends on the packing environment and the geometry of the molecules. In the ordered state, the alkyl chains preferentially assume an all-trans conformation. With increasing temperature, conformational transformation of the chains takes place, leading to a dynamically disordered phase (liquidlike). Although the translational freedom of the chains is restricted by the electrostatic binding of the headgroups to the substrate, the conformational transformation leads to chains with random conformation and destroys the two-dimensional order. The phase transition manifests itself in an increase in basal-plane spacing as well as in IR absorption frequency and carbon resonance shifts accompanied by an entropy change. The density of the organic ultrathin film confined between two silicate layers seems to decrease on heating across the phase transition, leading to an increase in volume and consequently in the organic layer thickness and in d-spacing, respectively. The basal-plane spacing of 3C18 and 4C18 is appreciably larger than that of C18 and 2C18, which is advantageous for exfoliation in the synthesis of polymer nanocomposites.

Cluster-Containing Polymers as Precursors for the Synthesis of Polymer Nanocomposites

Cluster-Containing Polymers as Precursors for the Synthesis of Polymer Nanocomposites