The structure and properties of a novel nanocomposite films from chitosan and layered zirconium phosphonate

A new type of layered zirconium phosphonate (zirconium glycine‐N, N‐dimethylphosphonate, abbreviated as ZGDMP), with functional group of ‐COOH, has been successfully prepared and characterized by Fourier transform infrared (FTIR) spectroscopy, X‐ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). To confirm the effect of the functional group ‐COOH on the structure and properties of composites, a series of chitosan/zirconium phosphonate modified by n‐butylamine (BA‐ZGDMP) nanocomposite films were prepared by casting process. FTIR spectra suggested that strong interactions existed between BA‐ZGDMP and chitosan matrix. Compared to neat CS film, tensile strength (σ_b) and elongation at break (ε_b) of the nanocomposite film improved by 35.1% and 15.6%, respectively, with loading ratio of just 1.0 wt %. In addition, the BA‐ZGDMP also improved the water resistance of the nanocomposites. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Effect of org-titanium phosphonate on the properties of chitosan films

A new type of titanium glycine-N,N-dimethylphosphonate Ti[(O₃PCH₂)₂NCH₂COOH] (TGDMP), with the functional groups –COOH, has been prepared first and then characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and transmission electron microscopy (TEM). Subsequently, chitosan/titanium glycine-N,N-dimethylphosphonate (CS/TGDMP-n) nanocomposite films of various compositions were prepared by solution casting method. The structure, morphology, and properties of nanocomposite films were investigated by FTIR, XRD, scanning electron microscopy (SEM), thermal gravimetric analysis (TGA), and tensile tests. The results showed that the mechanical properties of chitosan films were improved by the incorporation of TGDMP, and the samples kept at moisture environment showed the larger elongation and lower tensile strength than the dried counterparts. In addition, the CS/TGDMP-n films exhibited higher thermal stability and better moisture barrier property than neat CS films.     

Modification of structural,thermal, and electrical properties of PVA by addition of silicon carbide nanocrystals

SiC‐PVA nanocomposite films, synthesized using solution‐casting technique were structurally characterized using X‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy. Morphological studies of the SiC‐PVA nanocomposite films were carried out using Transmission electron microscopy (TEM) and Scanning electron microscopy (SEM). TEM analysis confirms that the size of SiC nanocrystals present in PVA matrix are 23 ± 9 nm, which is consistent with size calculated using XRD. SiC‐PVA nanocomposite films were further characterized for their thermal and electrical properties. Thermogravimetric/differential thermal analysis (TG/DTA) indicates that the char yield of nanocomposite films containing 3 wt % SiC nanocrystal is ～30% more than PVA. This increase in char yield is an indication of the potency of flame retardation of SiC‐PVA nanocomposite films. I‐V analysis reveals that Schottky mechanism is the dominant conduction mechanism which is responsible for the increase in conductivity of PVA with the addition of SiC nanocrystals. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42464.     

Assembly, characterization of Ag nanoparticles in P(AAm-co-NVP)/CS semi-IPN, and swelling of the resulting composite hydrogels

Silver nanoparticles (AgNPs) with controlled size and size distribution were prepared by an in situ chemical reduction route based on a microreactor template composed of poly(acrylamide-co-N-vinylpyrrolidone)/chitosan semi-interpenetrating network hydrogels, P(AAm-co-NVP)/CS semi-IPN, in the presence of sodium hypophosphite. The characterization of structures and morphologies of the as-fabricated P(AAm-co-NVP)/CS–Ag nanocomposite hydrogels was conducted on a Fourier transformation infrared spectroscopy (FTIR), scanning electron microscope (SEM), transmission electron microscope (TEM), and UV–vis spectrometer. The effect of various component proportions of the reactants on formation of AgNPs and swelling of the resulting P(AAm-co-NVP)/CS–Ag nanocomposite hydrogels was investigated. The experimental results indicated that the Ag grains were uniformly dispersed within P(AAm-co-NVP)/CS hydrogel networks in a spherical shape, and were stabilized by the semi-IPN structure and a complexation and/or electrostatic interaction between Ag⁺ cations and chemical functional groups, such as –OH, –CONH₂, –NH₂ or –C=O based on the semi-IPN structure reactor templates. The size of the majority of AgNPs ranges from 12 to 25 nm, depending on the three-network templates, the presence of functional groups as well as feed ratios of N-vinylpyrrolidone, acrylamide, and chitosan. Thermogravimetric analysis (TGA) provides the stability of the resulting nanocomposite hydrogels. The nanocomposite hydrogels demonstrate reduced swelling in comparison with the P(AAm-co-NVP)/CS ones. The kinetics modeling confirms that transport mechanism of the samples follows anomalous diffusion mode, and the kinetic parameters vary with the component ratios, and the maximal theoretical water volume S _∞ is well in agreement with the experimental values.     

Preparation and properties of castor oil‐based polyurethane/α‐zirconium phosphate composite films

Novel castor oil‐based polyurethane/α‐zirconium phosphate (PU/α‐ZrP) composite films with different α‐ZrP loading (0–1.6 wt %) and different NCO/OH molar ratios were synthesized by a solution casting method. The characteristic properties of the PU/α‐ZrP composite films were examined by Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), X‐ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and tensile testing. The results from Fourier transform infrared spectroscopy indicated that strong intermolecular hydrogen bonding formed between α‐ZrP and PU, XRD and SEM results revealed that the α‐ZrP particles were uniformly distributed in the PU matrix at low loading, and obvious aggregation existed at high loading. Because of hydrogen bonding interactions, the maximum values of tensile strength were obtained with 0.6 wt % α‐ZrP loading and 1.5 of NCO/OH molar ratio in the matrix. Evidence proved that the induced α‐ZrP used as a new filler material can affect considerably the mechanical and thermal properties of the composites. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Electrochemical synthesis and In situ spectroelectrochemistry of conducting NMPy‐TiO2 and ZnO polymer nanocomposites for Li secondary battery applications

Poly(N‐methylpyrrole) (PNMPy), poly(N‐methylpyrrole‐TiO₂) (PNMPy‐TiO₂), and poly (N‐methylpyrrole‐ZnO) (PNMPy‐ZnO) nanocomposites were synthesized by in situ electropolymerization for cathode active material of lithium secondary batteries. The charge–discharging behavior of a Li/LiClO₄/PNMPy battery was studied and compared with Li/LiClO₄/PNMPy‐nanocomposite batteries. The nanocomposites and PNMPy films were characterized by cyclic voltammetry, in situ resistivity measurements, in situ UV–visible, and Fourier transform infra‐red (FTIR) spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The differences between redox couples (ΔE) were obtained for polymer nanocomposites and PNMPy films. During redox scan, a negative shift of potential was observed for polymer nanocomposite films. Significant differences from in situ resistivity of nanocomposites and PNMPy films were obtained. The in situ UV–visible spectra for PNMPy and polymer nanocomposite films show the intermediate spectroscopic behavior between polymer nanocomposites and PNMPy films. The FTIR peaks of polymer nanocomposite films were found to shift to higher wavelengths in PNMPy films. The SEM and TEM micrographs of nanocomposite films show the presence of nanoparticle in PNMPy backbone clearly. The result suggests that the inorganic semiconductor particles were incorporated in organic conducting PNMPy, which consequently modifies the properties and morphology of the film significantly. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41526.     

Mesua ferrea L. seed oil based acrylate-modified thermostable and biodegradable highly branched polyester resin/clay nanocomposites

Mesua ferrea L. seed oil based highly branched polyester resin was modified by methyl methacrylate through grafting polymerization technique. The nanocomposites of this acrylate-modified polyester and 1–5 wt% loadings of organically modified montmorrilonite (OMMT) nanoclay were prepared by an ex situ technique using strong mechanical mixing and ultrasonication. Formation of nanocomposites was confirmed by X-ray diffractometeric (XRD), scanning electron microscopic (SEM) and transmission electron microscopic (TEM) analyses. The absence of d_{0 0 1} reflections of OMMT in XRD and TEM study revealed the partial exfoliation of OMMT by the polymer chain. The homogeneous surface morphology was also ascertained from SEM. Mechanical and thermal studies of the nanocomposites showed an appreciable improvement in tensile strength and thermal stability by OMMT loading. The enhancement of tensile strength by 2.5 times and thermal stability by 32 °C for 5 wt% OMMT filled nanocomposite was observed compared to that of pristine system. The rheological behavior of the nanocomposites was also investigated and shear thinning was observed. Biodegradation of the nanocomposite films was assayed using two strains of Pseudomonas aeruginosa, SD2 and SD3 and one strain of Bacillus subtilis, MTCC736. The nanocomposites exhibited enhanced biodegradability as compared to pristine acrylate modified polyester. All the results showed the potentiality of the nanocomposites as advanced thin film materials for suitable applications.     

Effect of different preparation routes on the structure and properties of rigid polyurethane‐layered silicate nanocomposites

To identify the effect of reactive preparation on the structure and properties of rigid polyurethane (PU)‐layered silicate nanocomposite, a range of nanocomposites were prepared by combining the various precursors in different sequences. The morphology of the samples was characterized by XRD and TEM. Tensile properties and dynamic mechanical thermal properties were measured. The reactions between the layered silicates and PU precursors were monitored via FTIR to gain an understanding of the participation of nanofiller in the polymerization reaction, and the impact of this on system stoichiometry. The XRD and TEM results provided evidence that morphology can differ significantly if different synthesis methods are used. However, the mechanical properties are dominated by the stoichiometry imbalance induced by the addition of the layered silicates. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2894–2903, 2006     

Polymeric carbon nanocomposites from multiwalled carbon nanotubes functionalized with segmented polyurethane

Multiwalled carbon nanotubes (MWNT) were functionalized with segmented polyurethanes (PU) by the “grafting to” approach. Raman and X‐ray photoelectron spectroscopy (XPS) spectra show that the sidewalls of MWNTs have been functionalized with acid treatment, and the amount of COOH increases with increasing acid treatment time. FTIR and X‐ray diffraction (XRD) spectra confirm that PU is covalently attached to the sidewalls of MWNTs by esterification reaction. Similar to the parent PU, the functionalized carbon nanotube samples are soluble in highly polar solvents, such as dimethyl sulfoxide (DMSO) and N,N‐dimethylformamide (DMF). The functionalized acid amount and the grafted PU amount were determined by thermogravimetric analyses (TGA). Comparative studies, based on SEM images between the PU‐functionalized and chemically defunctionalized MWNT samples, also reveal the covalent coating character. Dynamic mechanical analysis (DMA) of nanocomposite films prepared from PU and PU‐functionalized MWNTs show enhanced mechanical properties and increased soft segment T_g. Tensile properties indicate that PU‐functionalized MWNTs are effective reinforcing fillers for the polyurethane matrix. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

A facile route for the preparation of novel optically active poly(amide–imide)/functionalized zinc oxide nanocomposites containing pyromellitoyl-bis-l-phenylalanine moieties

In the present investigation, at first, the surface of zinc oxide (ZnO) nanoparticles was treated with a silane coupling agent of γ-methacryloxypropyltrimethoxy silane (KH570), which introduces organic functional groups on the surface of ZnO nanoparticles. Secondly, optically active poly(amide–imide) (PAI) was synthesized via solution polycondensation of N,N′-(pyromellitoyl)-bis-phenylalanine diacid chloride 1 (M-1) with 4,4′-diaminodiphenylsulfone 2 (M-2). The polycondensation of diacid chloride with aromatic diamine was carried out with N,N-dimethylacetamide/triethylamine systems. Finally PAI/ZnO nanocomposites (NCs) containing 4, 8, and 12% of nanoparticles were successfully fabricated through ultrasonic irradiation technique. The obtained NCs were characterized by Fourier transform-infrared (FT-IR) spectroscopy, thermogravimetry analysis, X-ray powder diffraction, UV–Vis spectroscopy, scanning electron microscopy (SEM), field emission-scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM). The FT-IR spectroscopy indicated that the silane coupling agent was anchored on the surface of ZnO nanoparticles. SEM, FE-SEM, and TEM images were showed ZnO nanoparticles were dispersed homogeneously in PAI matrix.     

Improving hydrophobicity of polyurethane by PTFE incorporation

A simple and facile method was established of incorporating polytetrafluoroethylene (PTFE) on to polyurethane (PU) to improve hydrophobicity of PU by incorporating low levels of fluorine at a molecular level. Nanocomposites were made by preparing PU in the presence of PTFE using seeded miniemulsion polymerization method. The resulting PTFE/PU nanocomposites were characterized by transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectrometry, differential scanning calorimetric, and thermo gravimetric analysis (TGA). FTIR and TEM indicated changes observed in their structure, size and morphology. The water contact angle of PTFE/PU nanocomposite films increased with increasing amount of PTFE and more on blending with silica nanoparticles but a slight decrease in thermal stabilities of SiO₂/PTFE/PU nanocomposites were noticed. The hydrophobicity imparted by PTFE to PU surface was found to be at its best for 1 : 2 PTFE/PU latex film. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42779.     

Synthesis and characterization of polyimide‐γ‐Fe2O3 nanocomposites

Novel polyimide‐γ‐Fe₂O₃ hybrid nanocomposite films (PI/γ‐Fe₂O₃) has been developed from the poly(amic acid) salt of oxydianiline with different weight percentages (5, 10, 15 wt %) of γ‐Fe₂O₃ using tetrahydrofuran (THF) and N,N‐dimethylacetamide (DMAc) as aprotic solvents. The prepared polyimide‐γ‐Fe₂O₃ nanocomposite films were characterized for their structure, morphology, and thermal behavior employing Fourier transform infrared spectroscopy (FTIR), scanning electron micrograph (SEM), transmission electron micrograph (TEM), X‐ray diffraction (XRD), ¹³C‐NMR, and thermal analysis (TGA/DSC) techniques. These studies showed the homogenous dispersion of γ‐Fe₂O₃ in the polyimide matrix with an increase in the thermal stability of the composite films on γ‐Fe₂O₃ loadings. Magnetization measurements (magnetic hysteresis traces) have shown very high values of coercive force indicating their possible use in memory devices and in other related applications. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 834–840, 2007     

Mechanical and UV absorption behavior of zinc oxide nanoparticles: reinforced poly(vinyl alcohol-<Emphasis Type="Italic">g</Emphasis>-acrylonitrile) nanocomposite films

In the present work PVA-g-PAN/ZnO nanocomposite films were prepared by free radical graft copolymerization of acrylonitrile on to PVA and subsequent in situ precipitation of ZnO nanoparticles into the polymer matrix. The films were characterized by FTIR, Raman spectroscopy, differential scanning calorimetry (DSC) and Scanning electron microscopy (SEM). The size of the crystallites and extents of crystallinity were ascertained by X-ray diffraction (XRD) analysis. The SEM with energy dispersive X-ray analysis (EDX) showed that the ZnO nanoparticles were uniformly dispersed within the host grafted copolymer matrix. The transmission electron microscopy (TEM) results clearly indicated that the size of nanoparticles varied in the range 10–30 nm. The UV-absorption properties showed that the films were capable of absorbing more than 95% of UV radiations. Photoluminescence (PL) measurements revealed the presence of defects in the synthesized nanocomposite films. The mechanical properties of the PVA-g-PAN/ZnO nanocomposites such as microhardness and tensile strength were also studied.     

Synthesis and characterization of elastomeric polyurethane and PU/clay nanocomposites based on an aliphatic diisocyanate

This investigation reports preparation of polyurethane and polyurethane/clay nanocomposites based on polyethylene glycol, isophorone diisocyanate (IPDI), an aliphatic diisocyanate and 1,4‐ Butanediol as chain extender by solution polymerization. In this case PU/clay nanocomposites were prepared via ex‐situ method using 1, 3, and 5 wt % of Cloisite 30B. Thermogravimetric analysis showed that the maximum decomposition temperature (T_max) of the PU/clay nanocomposite is much higher than the pristine PU. The tensile properties improved upon increasing the organoclay (Cloisite 30B) content upto 3 wt %, and then decreased to some extent upon further increasing the nanoparticle loading to 5 wt %. Optical properties of the nanocomposites were studied by UV‐vis spectrophotometer. X‐ray diffraction (XRD) and transmission electron microscopy (TEM) were used to study the morphology of the nanocomposites. It was observed that with the incorporation of 3 wt % nanoclay the crystallinity in PU nanocomposite increases, then diminishes with further loading. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3328–3334, 2013     

Synthesis and properties of castor oil-based waterborne polyurethane cloisite 30B nanocomposite coatings

Waterborne polyurethane dispersions (WPUDs) were synthesized successfully from castor oil-based polyol, isophorone diisocyanate and dimethylol propionic acid with NCO/OH ratio of 1.5. Different weight percentages of cloisite 30B (1, 2, and 3 wt%) were loaded with WPUDs to prepare nanocomposite films. Prepared prepolymer and nanocomposite films were characterized using FTIR, XRD, SEM, TEM, DSC, and TGA techniques, and coating properties, such as pencil hardness, abrasion resistance, impact resistance, and contact angle, were evaluated. The results obtained from different amounts of clay loading were compared with the pristine castor oil-based WPUDs. The FTIR spectra deconvolution technique was used to study the hydrogen bonding effect within the polymer with an increase in clay content. TGA analysis showed that the thermal stability of WPUDs increases with cloisite 30B (C30B) content. The surface morphology and hydrophilicity/hydrophobicity nature of the nanocomposite films were characterized using scanning electron microscopy and contact angle measurement. The results obtained from tensile tests indicated that the mechanical property of the dispersion system improved with C30B content. A high-performance castor oil-based nanocomposite coating with low volatile organic component can be targeted as an outcome of this work.     

Synthesis,characterisation and enhanced properties of polyimide/mica hybrid films

Polyimide/mica (PI/mica) hybrid films were prepared from pyromellitic dianhydride/4,4-bis(3-aminophenoxy)biphenyl (PMDA/4,3-BAPOBP) and mica in a solution of N,N-dimethylacetamide. The structure–property relationships of the composites were studied by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, ultraviolet–visible spectroscopy and differential scanning calorimetry. FTIR indicated successful preparation of PI/mica hybrid films. XRD and SEM results indicated that the mica was well dispersed in the PI matrix. The dependence of morphology, glass transition temperatures (T_g), dielectric properties and mechanical properties at room temperature of the hybrid films on the content of mica was discussed. It was observed that T_g, the breakdown strength and tensile strength of the hybrid films, could be simultaneously increased when the mica content was lower than 8?wt-%. Meanwhile, the dielectric constant and dielectric loss of PI/mica hybrid films increased with the increase in the mica content.     

Converting Layered Zinc Acetate Nanobelts to One-dimensional Structured ZnO Nanoparticle Aggregates and their Photocatalytic Activity

We were successful in synthesizing periodic layered zinc acetate nanobelts through a hydrothermal solution process. One-dimensional structured ZnO nanoparticle aggregate was obtained by simple thermal annealing of the above-mentioned layered ZnO acetate nanobelts at 300 °C. The morphology, microstructure, and composition of the synthesized ZnO and its precursors were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), and infrared spectroscopy, respectively. Low angle X-ray diffraction spectra reveal that as-synthesized zinc acetate has a layered structure with two interlayer d-spacings (one is 1.32 nm and the other is 1.91 nm). SEM and TEM indicate that nanobelt precursors were 100–200 nm in width and possesses length up to 30 μm. Calcination of precursor in air results in the formation of one-dimensional structured ZnO nanoparticle aggregates. In addition, the as-prepared ZnO nanoparticle aggregates exhibit high photocatalytic activity for the photocatalytic degradation of methyl orange (MO).     

Microstructural,Optical, Morphological,Luminescence and Electrical Properties of a CdO Nanocomposite Synthesized by a Chemical Route Assisted Microwave Irradiation Technique

This article reports a CdO nanocomposite successfully synthesized by a chemical route assisted microwave irradiation technique. Sodium dodecyl benzene sulfonate (SDBS) is a good surfactant and it is used in forming the nanocomposite. The microwave irradiation technique is simple and less time consuming for preparing a nanocomposite. The obtained products were characterized by different techniques such as X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FTIR), UV-Vis DRS, scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), room temperature photoluminescence (PL), and DC electrical conductivity. The grain size determined by the XRD pattern was found to be 20–40 nm. The lattice fringes and nanocomposite morphology particle size were obtained by TEM. The room temperature PL spectra reveal blue and red emissions. The calculated average electrical conductivity was around 5.1 × 10⁻⁸ to 2.02 × 10⁻⁸ S/cm.

     

Sea‐island polyurethane/polycarbonate composite nanofiber fabricated through electrospinning

Sea‐island polyurethane (PU)/polycarbonate (PC) composite nanofibers were obtained through electrospinning of partially miscible PU and PC in 3 : 7 (v/v) N,N‐dimethylformamide (DMF) and tetrahydrofuran (THF) mixture solvent. Their structures, mechanical, and thermal properties were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, thermogravimetric (TG), and differential scanning calorimetry (DSC). The structures and morphologies of the nanofibers were influenced by composition ratio in the binary mixtures. The pure PC nanofiber was brittle and easy to break. With increasing the PU content in the PU/PC composite nanofibers, PU component not only facilitated the electrospinning of PC but improved the mechanical properties of PU/PC nanofibrous mats. In a series of nanofibrous mats with varied PU/PC composition ratios, PU/PC 70/30 showed excellent tensile strength of 9.60 Mpa and Young's modulus of 55 Mpa. After selective removal of PC component in PU/PC composite nanofibers by washing with acetone, the residual PU maintained fiber morphology. However, the residual PU nanofiber became irregular and contained elongated indents and ridges along the fiber surface. PU/PC composite fibers showed sea‐island nanofiber structure due to phase separation in the spinning solution and in the course of electrospinning. At PC content below 30%, the PC domains were small and evenly dispersed in the composite nanofibers. As PC content was over 50%, the PC phases became large elongated aggregates dispersed in the composite nanofibers. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Novel biodegradable flame retardant,poly(butyl methacrylate)/sodium silicate/Mg(OH)2 nanocomposite

Flame retardant poly(butyl methacrylate)/sodium silicate/Mg(OH)₂ (MH) nanocomposite has been prepared via in situ emulsion polymerization of BMA, benzoyl peroxide, layered silicate, and conventional fire retardant additive, MH. The morphology, thermal stability, and flammability properties of the nanocomposite were characterized by IR, XRD, TEM, TGA, cone calorimetry, and limiting oxygen index. The thermal stability and the flame retardant properties of the polymer‐silicate‐MH showed significant improvements in the decomposition temperature and the lower heat release rates due to the formation of nanocomposites with layered silicates. Biodegradation testing by Bacillus cereus (gram‐positive) revealed the ecofriendly nature of the nanocomposite. POLYM. COMPOS., 2008. © 2007 Society of Plastics Engineers