Nanocomposites based on titanium dioxide,modified by β‐cyclodextrin containing copolymers

The range of titanium dioxide (TiO₂) samples, modified by β‐cyclodextrin containing copolymers was synthesized. The copolymers obtained were investigated by different methods, such as ultraviolet‐, Fourier transform infrared‐spectroscopy, thermal mass spectroscopy, thermogravimetric analysis, transmission electron microscopy, and scanning electron microscopy. The modification of TiO₂ is shown to promote a significant positive impact on the process of methyl orange absorption and photodegradation on its surface. The modified TiO₂‐photocatalysts prepared in such way could be promising objects for water purification from organic pollutants. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46373.     

Synthesis and characterization of polypyrrole dodecylbenzenesulfonate‐titanium dioxide nanocomposites

Nanocomposites of polypyrrole dodecylbenzenesulfonate‐titanium dioxide have been prepared from a colloidal solution of titanium dioxide (TiO₂) nanoparticles. The DC conductivity of samples with different concentrations of TiO₂ has been investigated under dark and light. The doping effect of TiO₂ has been characterized and evaluated by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy, and X‐ray diffraction. TEM shows that TiO₂ nanoparticles have strong effects on the morphology of composites, and conductivity measurements show that the conductivity first increases and then decreases as the percentage of TiO₂ is increased in the composites exhibiting a maximum in conductivity at about 20 wt % of TiO₂. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis and dielectric properties of polyaniline/titanium dioxide nanocomposites

Two series of polyaniline–TiO₂ nanocomposite materials were prepared in base form by in situ polymerization of aniline with inorganic fillers using TiO₂ nanoparticles (P25) and TiO₂ colloids (Hombikat), respectively. The effect of particle sizes and contents of TiO₂ materials on their dielectric properties was evaluated. The as-synthesized polyaniline–TiO₂ nanocomposite materials were characterized by transmission electron microscopy (TEM), Fourier transform infrared (FTIR), thermal analysis (DTA/TGA), and X-ray diffraction (XRD). Dielectric properties of polyaniline–TiO₂ nanocomposites in the form of films were measured at 1 KHz–1 MHz and a temperature range of 35–150 °C. Higher dielectric constants and dielectric losses of polyaniline–TiO₂ nanocomposites than those of neat PANI were found. PANI–TiO₂ nanocomposites derived from P25 exhibited higher dielectric constants and losses than those from Hombikat TiO₂ colloids. Electrical conductivity measurements indicate that the conductivity of nanocomposites is increased with TiO₂ content. The dielectric properties and conductivities are considered to be enhanced due to the addition of TiO₂, which might induce the formation of a more efficient network for charge transport in the base polyaniline matrix.     

Synthesis,chemical, and thermoelectric properties of n‐type π‐conjugated polymer composed of 1,2,4‐triazole and pyridine rings and its metal complexes

A soluble n‐type π‐conjugated polymer ( polymer 1 ) composed of a 1,2,4‐triazole ring substituted by a 4‐n‐octylphenyl subunit at the 4‐position of the 1,2,4‐triazole ring and pyridine‐2,5‐diyl rings was synthesized by Ni(cod)₂ (cod = 1,5‐cyclooctadiene) promoted dehalogenation polycondensation of 3,5‐bis(2‐bromopyridyl)‐4‐n‐octylphenyl‐1,2,4‐triazole ( monomer 1 ). A polymer complex ( polymer‐BiCl₃ ) was synthesized by the reaction of polymer 1 with BiCl₃. The UV–vis spectrum of polymer 1 exhibited an absorption maximum (λ_max value) at a longer wavelength than that exhibited by monomer 1 revealing that its π‐conjugation system was expanded along the polymer chain. Polymer 1 was electrochemically active in film, and the electrochemical reaction was accompanied with electrochromism. Thermoelectoric properties of polymer 1 and polymer‐BiCl₃ were investigated. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39928.     

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     

Synthesis and Characterization of 1‐Nitroguanyl‐3‐nitro‐5‐amino‐1,2,4‐triazole

The synthesis of 1‐nitroguanyl‐3‐nitro‐5‐amino‐1,2,4‐triazole (ANTA‐NQ) ( 1 ) with good yield and high purity is described. DSC analysis showed that the material displays good thermal stability. An X‐ray crystallographic analysis confirms the structure of this material, as well as displays intramolecular hydrogen bonding. A gas pycnometry density for this material was measured to be 1.79 g cm⁻³. The heat of formation of this material was also measured. These data, along with the molecular formula were used as inputs to calculate the detonation velocity and detonation pressure using the Cheetah thermochemical code. The sensitivity of this material towards impact, spark and friction was also measured, as well as its vacuum thermal stability. The 3‐azido derivative 2 was also prepared and its properties are described as well. The above data show that (ANTA‐NQ) may be a high performing material with low sensitivity and good thermal stability.     

Synthesis and investigation of oligosiloxanes containing γ‐trimethylsiloxy‐propyl or γ‐hydroxy‐propyl groups

Oligosiloxanes having different distributions of Si? H groups were prepared, and the addition of Si? H bonds to C?C double bounds of trimethyl(2‐propenyloxy)silane was utilized to obtain oligosiloxanes having different distributions of γ‐trimethylsiloxy‐propyl or γ‐hydroxy‐propyl groups as substituents. The oligosiloxanes were characterized by IR and ¹H‐NMR spectroscopy. Viscosity was studied to investigate the effects of the substituents. Differential scanning calorimetry (DSC) was used to investigate the thermal behaviour of these oligosiloxanes. It was found that they are completely amorphous materials and, hence, show only a glass transition. We found that the viscosities and glass transition temperatures of these materials increased with the increasing of the number of substituents. Hydrogen bonds have a considerable influence on the increase of the viscosities and glass transition temperatures of oligosiloxanes. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2431–2435, 2002     

Synthesis and characterization of pyridine and anthracene containing bismaleimides,bisnadimides and polyaspartimides

Three different novel diamines containing pyridine and anthracene moiety were prepared and subsequently converted into bismaleimides (BMI) and bisnadimides (BNI) and their structure was confirmed by elemental analysis, FT-IR, ¹H-NMR and ¹³C-NMR techniques. Chain extension of bismaleimides and bisnadimides was accomplished by incorporating various ether or ester groups. Owing to pendant anthracene moiety, pyridine unit and flexible linkages, the bismaleimides and bisnadimides were found to possess an excellent balance of properties; solubility and thermal stability and the curing behaviour was investigated by differential scanning calorimeter. In addition, a series of polyaspartimides containing anthracene and pyridine unit was prepared by the polyaddition of bismaleimides with various diamines via a Michael-type addition. The thermal stability of bismaleimides, bisnadimides and polyaspartimides was evaluated by thermo gravimetric analysis. All the polyaspartimides are soluble in many organic solvents and exhibit T _g in the range of 189–242 °C and 10% weight loss (T ₁₀) takes place in the range of 389–487 °C in N₂.     

Synthesis,characterization, and optimization of α‐Fe2O3/silica nanocomposites using homogenous precipitation method

The purpose of this study was to systematically synthesize and characterize the high surface area 10 wt% nanocomposites of α‐Fe₂O₃ (hematite)/silica using a simple and economically effective homogenous precipitation (HP) route via Response Surface Method combined with Central Composite Design (CCD). Accordingly, the RSM‐CCD approach including 20 experiments was designed to investigate the effects of three factors including concentration of iron chloride solution, pH and calcinations temperature on the final surface area of α‐Fe₂O₃/silica nanocomposites. The optimum surface area was 373 m²/g at the condition including iron chloride concentration of 0.018 mol/L, pH=8.95, and calcination temperature of 573°C.     

Synthesis of polyimides containing pyridine or triazole moiety to improve their adhesion to sputter-deposited copper

Polyimides containing pyridine as well as triazole were synthesized. The incorporation of pyridine or triazole improves the adhesion between polyimides and sputter-deposited copper. 4,4′-oxydianiline (ODA) was separately mixed with 2,6-diaminopyridine (DAP) and 3,5-diaminol,2,4-triazole (DATA), to form co-diamines. A series of polyimides was obtained in two steps by reacting co-diamines and 3,3′,4,4′-pyromellitic dianhydride (PMDA). The structure of the polyimides was verified by Fourier Transform Infrared spectroscopy (FT-IR) and Nuclear Magnetic Resonance (NMR). Their thermal, mechanical and dielectric properties were investigated. The rigidity of both pyridine and triazole moieties influences the coefficient of thermal expansion, the tensile strength and the elastic modulus of the films. The adhesion strength of the sputter-deposited copper to polyimide films was proportional to the functional group content. At a molar ratio of DAP to ODA of 1 : 6, the 90°-peel strength of copper/polyimide laminates reached a maximum of 990 J/m². At a molar ratio of DATA to ODA of 1 : 6, the 90°-peel strength of copper/polyimide laminates reached a maximum of 696 J/m². The corresponding polyimide films exhibited a good balance in thermal, mechanical and dielectric properties, as did the PMDA-ODA film. The locus of failure (LOF) examination by X-ray photoelectron spectroscopy (XPS) indicated that the LOF of laminates with low to moderate adhesion was mostly at the interface near the polyimide; the LOF of laminates with high adhesion was mostly in the polyimide. The N_1s core level spectra of the delaminated copper surface revealed a peak at 398.4 eV in copper/polyimide with DAP/ODA ratio of 1 : 6 and a peak at 398 eV in copper/polyimide with DATA/ODA ratio of 1 : 6, perhaps due to the formation of N-Cu charge-transfer complex. This complex substantially promoted the adhesion between sputter-deposited copper and polyimides.     

Synthesis and ultraviolet‐visible spectroscopic and electrochemical analyses of dyes derived from 2‐aminobenzothiazole,and study of their adsorption on titanium dioxide

A series of Schiff bases with hydroxyl anchoring group/s in various positions were synthesised. Their visible light absorption and electrochemical and physicochemical adsorption properties were investigated. Results show that the studied compounds have adequate highest‐occupied‐molecular‐orbital and lowest‐unoccupied‐molecular‐orbital levels that match with the conduction band of titanium dioxide and the redox potential of the electrolyte. Adsorption of azomethine compounds with hydroxyl group/s on titanium dioxide was studied. Experimental data show that the introduction of two β‐hydroxyethyl groups can greatly enhance the adsorption efficiency of the studied Schiff base on titanium dioxide. Sorption kinetics was measured for di‐(β‐hydroxyethyl)aminobenzyliden‐2‐aminobenzothiazol. Results show rapid initial sorption (<30 min), followed by a slower rate of increasing uptake between 0.5 and 6 h. Kinetic data were modelled using pseudo‐first‐order, pseudo‐second‐order, and intraparticle diffusion kinetics equations. These results indicate that the pseudo‐second‐order equation and intraparticle diffusion model can better describe the adsorption kinetics of di‐(β‐hydroxyethyl)aminobenzyliden‐2‐aminobenzothiazol onto titanium dioxide.     

Magnetic and electrical properties of polypyrrole nanocomposites with iron nanoparticles attached to 2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid

Polypyrrole (PPy) nanocomposites with iron nanoparticles attached to 2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid (AMP) were chemically prepared by varying the concentration of AMP using ammonium persulfate as an oxidant. The synthesized composites were characterized by using Fourier transform infrared (FTIR) spectroscopy, and their surface morphology and amended crystallinity were determined by using the transmission electron microscopy (TEM) and X‐ray diffraction (XRD), respectively. The electrical and magnetic properties of PPy–Fe–AMP composites were investigated at room temperature. The increase of AMP has brought out a significant increase of DC conductivity and magnetic saturation moment of the composites, which might have been caused by the increased mobility of charge carriers due to the hydrophilic AMP components. POLYM. COMPOS., 35:364–371, 2014. © 2013 Society of Plastics Engineers     

Synthesis and thermal properties of polystyrene/montmorillonite nanocomposites by γ‐ray radiation polymerization

Polystyrene/montmorillonite nanocomposites were prepared by γ‐ray radiation polymerization. X‐ray diffraction and high‐resolution transmission electron microscopy confirmed that polystyrene (PS) could be easily inserted between the sheets of montmorillonite (MMT) to form intercalated nanocomposites. In these PS/MMT nanocomposites, the distance between the sheets of MMT was barely influenced by varying the content of the MMT. Thermal stabilities of the samples were studied by thermal gravimetric analysis and differential scanning calorimetry. The glass‐transition temperature of PS/MMT nanocomposites was obviously higher than that of the pure PS. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1692–1696, 2003     

Synthesis of water‐insoluble functional copolymers containing amide,amine, and carboxylic acid groups and their metal‐ion‐uptake properties

The crosslinked poly[N‐(3‐dimethylamino)propylmethacrylamide] [P(NDAPA)] and poly[N‐(3‐dimethylamino)propylmethacrylamide‐co‐acrylic acid] [P(NDAPA‐co‐AA)] were synthesized by radical polymerization. The resins were completely insoluble in water. The metal‐ion‐uptake properties were studied by a batch equilibrium procedure for the following metal ions: silver(I), copper(II), cadmium(II), zinc(II), lead(II), mercury(II), chromium(III), and aluminum(III). The P(NDAPA‐co‐AA) resin showed a lower metal‐ion affinity than P(NDAPA), except for Hg(II), which was retained at 71% at pH 2. At pH 5, the resin showed a higher affinity for Pb(II) (80%) and Cu(II) (60%), but its affinity was very low for Zn(II) and Cr(III). The polymer ligand–metal‐ion equilibrium was achieved during the first 20 min. By changing the pH, we found it possible to remove between 60 and 70% of Cd(II) and Zn(II) ions with (1M, 4M) HClO₄ and (1M, 4M) HNO₃. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:5232–5239, 2006     

α‐Thiophene end‐capped styrene copolymer containing fullerene pendant moieties: Synthesis,characterization, and gas sensing properties

We report the synthesis, characterization, and gas sensing properties of a styrene copolymer bearing α‐thiophene end group and fullerene (C₆₀) pendant moieties P(S‐co‐CMS‐C₆₀). First, the copolymer of styrene (S) and chloromethylstyrene (CMS) monomers was prepared in bulk via a bimolecular nitroxide‐mediated radical polymerization (NMP) technique using benzoyl peroxide (BPO) as the radical initiator and nitroxy‐functional thiophene compound (Thi‐TEMPO) as the co‐radical and this gave α‐thiophene end‐capped copolymer P(S‐co‐CMS). The chloromethylstyrene units of P(S‐co‐CMS) allowed further side‐chain functionalization onto P(S‐co‐CMS). The obtained P(S‐co‐CMS) was then reacted with sodium azide (NaN₃) and this led to the copolymer with pendant azide groups, P(S‐co‐CMS‐N₃), and then grafted with electron‐acceptor C₆₀ via the reaction between N₃ and C₆₀. The final product was characterized by using NMR, FTIR, and UV–vis methods. Electrical characterization of P(S‐co‐CMS‐C₆₀) thin film was also investigated at between 30 and 100 °C as the ramps of 10 °C. Temperature dependent electrical characterization results showed that P(S‐co‐CMS‐C₆₀) thin film behaves like a semiconductor. Furthermore, P(S‐co‐CMS‐C₆₀) was employed as the sensing layer to investigate triethylamine (TEA), hydrogen (H₂), acetone, and ethanol sensing properties at 100 °C. The results revealed that P(S‐co‐CMS‐C₆₀) thin film has a sensing ability to H₂. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43641.     

Scratch behavior of epoxy nanocomposites containing α‐zirconium phosphate and core‐shell rubber particles

The effects of nanoscale core‐shell rubber (CSR) particles and α‐zirconium phosphate (ZrP) nanoplatelet fillers on the scratch behavior of epoxy have been examined using a newly established ASTM scratch testing method. The critical load for onset of microcrack formation is utilized to determine scratch resistance of the epoxy nanocomposites. Optical microscopy and scanning electron microscopy were performed to determine failure and fracture patterns caused by the scratch. The findings of this study suggest that the introduction of nanoparticles or nanoplatelets does not necessarily enhance the scratch resistance of epoxy. This implies that increases in ductility and fracture toughness alone, i.e., the epoxy/CSR case, and enhancements in modulus and tensile strength alone, i.e., the epoxy/ZrP case, will not necessarily improve scratch resistance of epoxy matrix. A combination of material property attributes is needed to prepare scratch resistant polymers. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers     

Synthesis of nano β‐TCP and the effects on the mechanical and biological properties of β‐TCP/HDPE/UHMWPE nanocomposites

High density polyethylene/tricalcium phosphate/ultra high molecular weight polyethylene (TCP/HDPE/UHMWPE) Nanocomposite as an orthopedic biomaterial (with better properties toward TCP/HDPE composite) was obtained. To evaluate the capability of this nanocomposite as a material for bone tissue replacement, mechanical and biological assessments were performed. In this study, nanosize β‐TCP powders with average grain size of 100 nm were synthesized by chemical precipitation method and characterized by means of X‐ray diffraction (XRD), Fourier‐transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). To evaluate the mechanical properties of this biomaterial, tensile properties were obtained for the material. Results showed that by increasing the weight percentage of β‐TCP, the elastic modulus increases, elongation at yield decreases and with no significant change in tensile strength. SEM micrographs of cryogenic fracture surface of samples indicated that distribution of nano powders in matrix is homogeneous. In vitro biological evaluations on the samples were done by performing cytotoxicity (MTT assay), alkaline phosphatase enzyme, and cell attachment tests. In all of the tests, osteoblast cells were used. Results of biological tests showed that the samples are biocompatible and they have no toxicity. Also, SEM observations demonstrated that the cells can attach to surface of nanocomposite samples, which reveals osteoconductivity of the surface. POLYM. COMPOS., 31:1745–1753, 2010. © 2010 Society of Plastics Engineers.     

Poly(2‐) and (3‐aminobenzoic acids) and their copolymers with aniline: Synthesis,characterization, and properties

Poly(2‐aminobenzoic acid) and poly(3‐aminobenzoic acid) were synthesized by chemical polymerization of the respective monomers with aqueous 1M hydrochloric acid and 0.49M sodium hydroxide, using ammonium persulfate as an oxidizing agent. In addition, polymerization in an acid medium was carried out in the presence of metal ions, such as Cu(II), Ni(II), and Co(II). Poly(2‐aminobenzoic acid‐co‐aniline) and poly(3‐aminobenzoic acid‐co‐aniline) were synthesized by chemical copolymerization of aniline with 2‐ and 3‐aminobenzoic acids, respectively, in aqueous 1M hydrochloric acid. The copolymers were synthesized at several mole fractions of aniline in the feed and characterized by UV–visible and FTIR spectroscopy, the thermal stability, and the electrical conductivity. Metal ions, such as Cu(II), Ni(II), and Co(II), were incorporated into homo‐ and copolymers by the batch method. The percentage of metal ions in the polymers was higher in the copolymers than in the homopolymers. The thermal stability of the copolymers increased as the feed mole fraction of aniline decreased and varied with the incorporation of metal ions in the polymers. The electrical conductivity of the homo‐ and copolymers was measured, which ranged between 10^?3 and 10^?10 S cm^?1. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2641–2648, 2003     

Preparation and characterization of polystyrene/titanium dioxide composite particles containing organic ultraviolet‐stabilizer groups

Polystyrene/titanium dioxide (TiO₂) composite particles containing organic ultraviolet (UV)‐stabilizer groups were prepared by the emulsion copolymerization of styrene and 2‐hydroxy‐4‐(3‐methacryloxy‐2‐hydroxylpropoxy)benzophenone with sodium sulfopropyl lauryl maleate as a surfactant in the presence of rutile TiO₂ modified with 3‐(trimethoxysilyl) propyl methacrylate, and the product was poly[styrene‐co‐sodium sulfopropyl lauryl maleate‐co‐2‐hydroxy‐4‐(3‐methacryloxy‐2‐hydroxylpropoxy) benzophenone] [poly(St‐co‐M12‐co‐BPMA)]/TiO₂ composite particles. The structures of the composite particles were characterized with Fourier transform infrared spectroscopy, ultraviolet–visible (UV–vis) absorption spectroscopy, thermogravimetric analysis, and differential scanning calorimetry. The Fourier transform infrared and UV–vis measurements showed that poly(St‐co‐M12‐co‐BPMA) was grafted from the surface of TiO₂, and this copolymer possessed a high absorbance capacity for UV light, which is very important for improving the UV resistance of polystyrene. The thermogravimetric analysis measurements indicated that the percentage of grafting and the grafting efficiency could reach 513.9 and 59.9%, respectively. The differential scanning calorimetry measurement indicated that the glass‐transition temperature of the poly(St‐co‐M12‐co‐BPMA)/TiO₂ composite particles was higher than that of poly (St‐co‐M12‐co‐BPMA).These research results are very important for preparing polystyrene with high UV resistance. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Synthesis and properties of new polyamide/multiwalled carbon nanotube nanocomposites containing a pyridine group

The effects of multiwalled carbon nanotubes (MWCNTs) on the thermal properties and flame retardancy of a new polyamide (PA) derived from glutaric acid and aromatic diamine were investigated in this work. The synthesized PA containing pyridine and trialkylamine groups was characterized by ¹H NMR and SEC. The PA unit structure was geometrically optimized at the B₃LYP/6‐311⁺⁺G(d, p) level of theory. PA showed a glass transition temperature of 151 ºC. PA nanocomposites containing two different amounts of MWCNTs were prepared via the solution intercalation technique with the solvent N,N‐dimethylacetamide. Transmission electron microscopy showed that MWCNTs were exfoliated in the polymer matrix, resulting in well‐dispersed morphologies at 3 wt% MWCNT content. The redox behaviors of PA and the nanocomposites were examined using cyclic voltammetry (CV). PA showed a reversible oxidation process in the CV scan. Thermal and flammability properties of the nanocomposites were studied by TGA in nitrogen and air, DSC and with a microscale combustion calorimeter. The TGA results showed that the addition of MWCNTs resulted in a substantial increase in the thermal stability and char yields of the nanocomposites compared with neat PA. The heat release rate and total heat release were significantly reduced in the presence of MWCNTs. © 2013 Society of Chemical Industry