Search

The preparation of 2,6-Bis(m-amino phenoxy) benzoyl naphthalene-based polyimides for solid polymer electrolytes was reported. Li-salt and PEO bearing polyimide membranes were prepared. Thermo-gravimetric analysis results reveal that the PI/PEO/LiCF3SO3 polymer electrolyte membranes are thermally stable up to 500°C. The “Tg” values are in the range 167–221.5°C according to dynamic mechanical analysis (DMA). The conductivities of Li-salt and PEO containing PI membranes are in the range of 10−7–10−5 S/cm. The conductivity increases with incorporation of PEO and Li+ concentration. The linear sweep voltammetry experiments showed that no peaks were observed between 1.75 and 4.5 V.

Bis[(4 -β-(2-bromopropanoate)ethoxy)phenyl]phenylphosphine oxide was used for the first time as the initiator of atom transfer radical polymerization of styrene and methyl methacrylate in the presence of CuBr/N, N,N′, N″, N″-pentamethyldiethylenetriamine as catalyst/ligand and dimethyl sulfoxide as solvent. The presence of phosphine oxide linkages in the backbone gives the polymers special properties; low Tg, high char yield, and decreases the oxygen induction time value. A linear increase of number average molecular weight (Mn) versus monomer conversion was observed, and the molecular weight distribution was relatively narrow (Mw/Mn = 1.1–1.3). FTIR, 1HNMR, gel permeation chromatography, ultraviolet spectroscopies were used for the characterization of the related polymers. The thermal properties of these polymers were investigated by differential scanning calorimetry and thermogravimetric analysis. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

In this study, a series of PI/TiO2 nanohybrid materials were prepared from polyamic acid of 3,3′,4,4′-benzophenonetetracarboxylic dianhydride/3,3′-diaminodiphenyl sulfone, and titania precursor by the sol-gel method. The titania content in the hybrid system was varied from 0 to 5 wt %. The physical and mechanical properties of the hybrids such as refractive index, optical transmission, and tensile strength were investigated. It was determined that incorporation of titania precursor into the PI matrix improved the refractive indices and tensile modulus of the hybrid films. It was observed that the optical transmittance and tensile strength of the nanohybrids were slightly decreased with the increasing titania content. It was determined that the hybrid films might have enhanced the UV shielding properties compare to the PI films. Furhermore, the hybrid materials showed better thermal stability than the PI. SEM studies demonstrated that titania particles (1 and 3 wt %) were distributed homogeneously through the PI matrix. The effect of the titania content in the PI on DC conductivity and dielectric constant were also analyzed. For the PI film containing 5 wt % titania, activation energy value increased to 1.0 eV from the value of 0.65 eV. DC conductivity value of the films depending on titania content varied between 3.0 × 10−11 and 1.4 × 10−10 S/cm at room temperature. Relative dielectric constants of the films were calculated from capacitance measurements depending on frequency (40–100 kHz) at different temperatures (303–360 K). The values increased with the increasing titania content. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Polyimide (PI)/hexagonal boron nitride (h-BN) composites were produced via the thermal imidization procedure from solution mixtures of a polyamicacid, which is prepared from 3,3′,4,4′-benzophenonetetracarboxylic dianhydride and 3,3′-diaminodiphenyl sulfone (DADPS) in N-methyl-2-pyrrolidone (NMP), and alkoxysilane functionalized h-BN. The structure, thermostability, thermal behavior, and surface properties of the resulting materials were characterized by means of Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM). The thermal characteristics of PI/h-BN films were better than the pure PIs. The physical and mechanical properties of the films were evaluated by various techniques such as contact angle, chemical resistance, and tensile tests. The flame retardancy of the composite materials was also examined by the limiting oxygen index (LOI). The experiments showed that the LOI values of PIs increased from 32 to 43 for the materials containing hexagonal boron nitride. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

A branched methacrylated poly(caprolactone-co-lactic acid) and methacrylated poly(tetramethylene ether glycol) (PTMG-IEM) resins were synthesized. 1H-NMR spectroscopy, attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) spectroscopy, and gel permeation chromatography confirmed the chemical structures of copolymers. The photoinitiated polymerization of formulation composed of various amounts of methacrylated poly(caprolactone-co-lactic acid), PTMG-IEM, poly(ethylene glycol) diacrylate, water, and photoinitiator were performed. The curing reactions were followed by photo-DSC (Differential scanning calorimetry). Gel fraction was calculated from the insoluble part and found as ≥93%. Swelling and contact angles were measured, and all increased with the increasing amount of PTMG-IEM in network formulations. In vitro degradation studies were performed at 37 °C in phosphate-buffered saline (pH 7.4). Collagen-modified polymers were also prepared and introduced as a bioactive moiety to modify the polymer to enhance cell affinity. To compare the cell adhesion affinity to the polymer with and without collagen, cell growth experiments were performed. The results showed that collagen improves the cell adhesion onto the polymer surface. With the increasing amount of collagen, cell viability increases 86% (ECV304, p

In this study, a series of ultraviolet (UV)-curable organic–inorganic hybrid coating materials containing phosphorus were prepared by sol–gel approach from acrylate end-capped urethane resin, acrylated phenyl phosphine oxide oligomer (APPO), and inorganic precursors. TEOS and MAPTMS were used to obtain the silica network and Ti:acac complex was employed for the formation of the titania network in the hybrid coating systems. Coating performance of the hybrid coating materials applied on aluminum substrates was determined by the analysis techniques, such as hardness, gloss, impact strength, cross-cut adhesion, taber abrasion resistance, which were accepted by international organization. Also, stress–strain test of the hybrids was carried out on the free films. These measurements showed that all the properties of the hybrids were enhanced effectively by gradual increase in sol–gel precursors and APPO oligomer content. The thermal behavior of the hybrid coatings was investigated by thermogravimetric analysis (TGA) analysis. The flame retardancy of the hybrid materials was examined by the limiting oxygen index (LOI); the LOI values of pure organic coating (BF) increased from 31 to 44 for the hybrid materials containing phosphorus (BF-P:40/Si:10). The data from thermal analysis and LOI showed that the hybrid coating materials containing phosphorus have higher thermal stability and flame resistance properties than the organic polymer. Besides that, it was found that the double bond conversion values for the hybrid mixtures were adequate in order to form an organic matrix. The polycondensation reactions of TEOS and MAPTMS compounds were also investigated by 29Si-NMR spectroscopy. SEM studies of the hybrid coatings showed that silica/titania particles were homogenously dispersed through the organic matrix. In addition, it was determined that the hybrid material containing phosphorus and silica showed fibrillar structure. Copyright © 2009 John Wiley & Sons, Ltd.

A series of ultraviolet (UV)-curable, boron- containing hybrid coatings were prepared by an anhy- drous sol-gel technique from a mixture of an acrylated bisphenol A based epoxy resin, methacryloxymethyl trie- thoxysilane, and boric acid. The use of boric acid allowed the hydrolysis and condensation of hybrid silicon alkox- ides without the further addition of water or a catalyst. The chemical structure of the boron-containing hybrid coatings was characterized with Fourier transform infra- red, real-time infrared, and 29 Si cross-polarization/magic- angle spinning NMR techniques. UV-curable coatings were applied to polycarbonate and Plexiglas substrates. The physical and mechanical properties of the UV-cured coatings (e.g., pendulum hardness, pencil hardness, con- tact angle, gel content, methyl ethyl ketone rubbing test, tensile test, abrasion resistance, chemical resistance, neutron absorption, and limiting oxygen index) were examined. The hybrid coatings showed a significant enhancement in their radiation-shielding properties. The thermal behavior of the coatings was also evaluated. It was observed that the thermal stability of the coatings mainly depended on their boron and silicate contents. The results of all analyses of the free films and coatings were examined. V C 2010 Wiley Periodicals, V C 2010 Wiley Periodicals, Inc. J Appl Polym Sci 120: 2112-2121, 2011

In this article, a series of novel polyimide/silica (PI/SiO2) nanocomposite coating materials were prepared from tetraethoxysilane (TEOS), γ-glycidyloxypropyltrimethoxysilane (GOTMS), and polyamic acid (PAA) via sol-gel technique. PAA was prepared by the reaction of 3,3′,4,4′-benzophenone tetracarboxylic dianhydride (BTDA) and bis (3-aminophenyl) phenyphosphine oxide (BAPPO) in N-methyl-2- pyrrolidone (NMP). BAPPO was synthesized hydrogenation of bis (3-nitrophenyl) phenyphosphine oxide (BNPPO) in the presence of Pd/C. The silica content in the hybrid coating materials was varied from 0 to 20 wt %. The molecular structures of the composite materials were analyzed by means of FT-IR and 29Si-NMR spectroscopy techniques. The physical and mechanical properties of the nanocomposites were evaluated by various techniques such as, hardness, contact angle, and optical transmission and tensile tests. These measurements revealed that all the properties of the nanocomposite coatings were improved noticeable, by the addition of sol-gel precursor into the coating formulation. Thermogravimetric analysis showed that the incorporation of sol-gel precursor into the polyimide matrix leads to an enhancement in the thermal stability and also flame resistance properties of the coating material. The surface morphology of the hybrid coating was characterized by scanning electron microscopy (SEM). SEM studies indicated that nanometer-scaled inorganic particles were homogenously dispersed throughout the polyimide matrix © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

UV-curable fluorinated organic–inorganic hybrid coatings were prepared by the sol–gel technique. Perfluorinated urethane modified alkoxysilane was synthesized by the reaction between perfluoro alcohol and 3-isocyanatopropyltrimethoxysilane. The prepared formulations were applied onto poly(methyl methacrylate) (PMMA) and acrylonitrile butadiene styrene (ABS) panels and polymerized by UV-curing. The properties of the hybrid coatings such as hardness, chemical resistance, thermal stability, surface morphology, double bond conversion, and also contact angle measurements were investigated. Contact angle measurements have shown that the addition of fluorinated silane precursor to the hybrid system improved the water repellency and increased the contact angle from 65° to 106°. Copyright © 2009 John Wiley & Sons, Ltd.

In the present study, maleimide-modified epoxide resin containing UV-curable hybrid coating materials were prepared and coated on polycarbonate substrates in order to improve their surface properties. UV-curable, bismaleimide-modified aliphatic epoxy resin was prepared from N-(p-carboxyphenyl) maleimide (p-CPMI) and cycloaliphatic epoxy (Cyracure-6107) resin. The structure of the bismaleimide modified aliphatic epoxy resin was analyzed by FTIR and the characteristic absorption band for maleimide ring was clearly observed at 3100 cm−1. Silica sol was prepared from tetraethylorthosilicate (TEOS) and methacryloxy propyl trimethoxysilane (MAPTMS) by sol–gel method. The coating formulations with different compositions were prepared from UV-curable bismaleimide-based epoxy oligomer and sol–gel mixture. The molecular structure of the hybrid coating material was analyzed by 29Si-CP/MAS NMR spectroscopy techniques. In the 29Si CP/MAS NMR spectrum of the hybrid coating, mainly two kinds of signals were observed at −68 and −110 ppm that correspond to T3 and Q4 peaks, respectively. This result shows that a fully condensed structure was obtained. The thermal and morphological properties of these coatings materials were investigated by using TGA and SEM techniques. Hardness and abrasion resistance properties of coating materials were examined and both were found to increase with sol–gel precursor content of the coating. The photopolymerization kinetics was investigated by using RT-IR. 70% conversion was attained with the addition of 15 wt% of BMI resin into the acrylate-based coating formulation. It was found that the UV-curable organic–inorganic hybrid coatings improved the surface properties of polycarbonate. Copyright © 2009 John Wiley & Sons, Ltd.

The objective of this study was to synthesize a new bifunctional photoinitiator by the reaction between 1-hydroxy-cyclohexyl-phenyl-ketone and 3-isocyanato propyl trimethoxysilane (ICPTMS) and examine its capability in the photoinitiation process comparing it with the unmodified photoinitiator. This new photoinitiator also acts as a coupling agent for inorganic and organic phases. Therefore, its effect on the physical and mechanical properties of UV-curable transparent organic-inorganic hybrid coatings was investigated. The presence of the new bifunctional photoinitiator and TEOS, increased the abrasion resistance and also improved the hardness of the polymeric films.

In the present work adipic acid modified and methacrylated bisphenol A based epoxy resins were prepared. The structures of oligomers were characterized by FT-IR. UV curable clear coatings were applied on aluminum substrates. The physical and mechanical properties of UV-cured coatings such as gel content, solvent resistance, hardness, gloss, flexibility and tensile tests were examined. In addition, the thermal behavior of coatings was also evaluated. It is observed that the tensile properties and thermal stabilities of modified epoxy methacrylate coatings mainly depend on the adipic acid content. The best results were obtained with 5 wt% adipic acid modification. Copyright © 2007 John Wiley & Sons, Ltd.

Acrylated epoxidized soybean resin has been utilized to immobilize the α-amylase via UV-curing technique. Among the numerous methods that exist for enzyme immobilization, entrapment and covalent binding are the focus of this study. The properties of immobilized enzyme were investigated and compared with those of the free enzyme. Upon immobilization by the two methods, the catalytic properties of the enzyme were not considerably changed as compared with that of nonimmobilized form; only the pH profile was broadened for the immobilized enzyme. The free enzyme lost its activity completely in 20 days, where as storage and repeated usage capability experiments demonstrated higher stability for the immobilized form. Immobilized enzyme prepared by attachment method possesses relatively higher activity compared with the activity of those obtained by entrapment method. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4757–4761, 2006

Various UV-curable acrylated urethane prepolymers based on tolylene-2,4-diisocyanate (TDI), poly(ethylene glycol) (PEG 400), and 2-hydroxyethyl methacrylate (HEMA) were synthesized. The effects of reactive diluent types, the composition of the products and of different humidity conditions on mechanical properties of cured films were investigated. Effects of diethylene glycol diacrylate (DEGDA) and thiodiethylene glycol diacrylate (TDGDA) as reactive diluents on tensile strength, elongation and Young's modulus values of the UV cured films were examined systematically. The results show that the increase of relative humidity from 50 to 95% leads to a decrease in tensile strength and Young's modulus values of polymeric films. The decrease of these mechanical properties in high relative humidity is due to the formation of hydrogen bonding in the polymer chain caused by water molecules. Verschiedene UV-hartbare Acrylat-Urethan-Prapolymere auf Basis von Toluol-2,4-diisocyanat (TDI), Polyethylenglykol (PEG 400) und 2-Hydroxyethylmethacrylat (HEMA) wurden synthetisiert. Die Einflusse von reaktiven Verdunnungsmitteln, von der Produktzusammensetzung und von verschiedenen Feuchtigkeitsgehalten auf die mechanischen Eigenschaften geharteter Filme wurden untersucht. Die Effekte von Diethylenglykoldiacrylat (DEGDA) und Thiodiethylenglykoldiacrylat (TDGDA) als reaktive Verdunnungsmittel auf Zugfestigkeit, Dehnung und E-Modul der UV-geharteten Filme wurden systematisch untersucht. Die Ergebnisse zeigen, das ein Anstieg der relativen Feuchtigkeit von 50 auf 95% zu einem Abfall der Zugfestigkeit und des E-Moduls der Polymerfilmer fuhrt. Dies last sich auf die Bildung von Wasserstoffbrucken durch Wassermolekule in der Polymerkette zuruckfuhren.

A UV-curable acrylated urethane prepolymer was synthesized from tolylene-2,4-diisocyanate (TDI), a polyether polyol (Arcol 1131) and endcapped with 2-hydroxyethyl methacrylate (HEMA) by addition reaction in the presence of dibutyltin dilaurate as catalyst. UV curing was performed with either diethylene glycol diacrylate or thiodiethylene glycol diacrylate as reactive diluent. The effects of reactive diluent types, their concentrations and the humidity of environment on mechanical properties of cured films were investigated. Changes in the tensile strength, elongation and Young's modulus values of the cured films upon addition of reactive diluents with different concentrations were related to the effect of the diluent on the crosslinking density of cured films. The increase of relative humidity from 50 to 95% caused a decrease of tensile strength and Young's modulus values of cured films. It is proposed that the decrease of these physical properties in high relative humidity is due to the formation of hydrogen bonding in polymer chains caused by water molecules. Ein UV-hartbares acrylhaltiges Urethanprepolymeres wurde durch Umsetzung von Toluylen-2,4-diisocyanat (TDI) mit einem Polyetherpolyol (Arcol 1131) und 2-Hydroxyethylmethacrylat (HEMA) in Gegenwart von Dibutylzinn-dilaurat als Katalysator hergestellt. Die UV-Hartung wurde entweder mit Diethylenglykoldiacrylat oder Thiodiethylenglykoldiacrylat als reaktiver Verdunnungskomponente durchgefuhrt. Der Einflus des reaktiven Verdunners, seiner Konzentration und der Umgebungsfeuchtigkeit auf die mechanischen Eigenschaften der vernetzten Produkte wurde untersucht. Die Veranderungen der Zugfestigkeit, der Dehnung und des E-Moduls der vernetzten Polymerfilme mit der Konzentration der reaktiven Verdunnungsmittel wurden auf den Einflus der Verdunnungskomponente auf die Vernetzungsdichte der Filme zuruckgefuhrt. Die Abnahme der Dehnungs- und der E-Modulwerte der vernetzten Polymerfilme mit steigender relativer Feuchtigkeit von 50% auf 95% wird mit der Bildung von Wasserstoffbrucken zwischen den Polymerketten erklart.

Synthesis and characterization of the novel sulfonated BAPPO monomer and its use in the synthesis of a new phosphine oxide-based sulfonated polyimide are described. BTDA, 6FDA, and DDS were used as monomers in the polyimide synthesis. Sulfonated polyimide membranes were obtained by a solution thermal imidization method. The thermal behavior of the polymers was investigated by DSC and TGA. The morphological structure of the membranes was investigated by tapping-mode AFM. The proton conductivities of the sulfonated polyimide increased regularly as a function of sulfonated diamine content. The conductivities are good compared to typical proton exchange membranes.