A new confined p-phenylenevinylene (PPV)-type polymer (BPAF-PPV) has been synthesized using Wittig condensation. The chemical structure of the polymer was well defined by ¹H-NMR, ¹³C-NMR, and FT-IR spectroscopic analysis. BPAF-PPV contains oligomeric PPV units separated by hexafluoroisopropylidene groups in the main chain; it is fully soluble in common organic solvents and has a number-average molecular weight of 4570 g mol^–1. Differential scanning calorimetry indicates that BPAF-PPV is amorphous and displays a glass transition temperature of 114 °C. The optical properties of the polymer were investigated by UV-visible absorption and photoluminescence spectroscopies. Its thin film showed a blue photoluminescence with a narrow emission spectrum. A high photoluminescence quantum efficiency of about 83% was determined in dilute solution. From the cyclic voltammetry analysis, the electrochemical bandgap was estimated to be 3.08 eV. A single-layer diode device of the configuration indium-tin oxide/BPAF-PPV/aluminium has been fabricated and has a relatively low turn-on voltage of 3.0 V.

A new copolymer based on gamma radiation initiated polymerization of methyl methacrylate in the presence of aniline was prepared for potential applications in electric fields. The electrical properties of the new material, such as permittivity, relaxation time and ac conductivity, were compared to the properties of poly(methyl methacrylate). The frequency and irradiation dose dependency of the loss tangent factor and dielectric constant showed a Debye dielectric relaxation process. The main objective of the dielectric investigation in this study was to provide a better understanding for the correlated hopping electron process involved in the conduction. On the other hand, for the ac conductivity, at room temperature, there was a deviation in the conduction mechanism of the correlated barrier hopping of electrons between paired and random defects. This deviation showed a maximum value for aniline methyl methacrylate copolymer irradiated at a dose of 30 kGy. The analysis of the data of the dielectric loss showed a well-defined peak at a frequency assigned to dipole relaxations in the system. The results indicated that the gamma irradiation results in the formation of some traps in the energy gap, which reduce the movement of the charge carriers. Also it can be stated that aniline acts as an effective protection agent against structural damage caused by gamma radiation in the copolymer matrix.

In this study, a novel aromatic diamine containing thioether and pyridine linkages, 2,6-bis[4-(4-aminophenylenesulfanyl)phenyl]-2-phenylpyridine (BASPP), was synthesized and characterized. The BASPP, along with several other sulfur-containing diamines, including 4,4'-(p-phenylenedisulfanyl)dianiline (2SPDA), 4,4'-bis(p-aminophenylsulfanyl)biphenyl (2SBPA), 4,4'-sulfonylbis[(p-phenylenesulfanyl)aniline] (BADPS), and 2,7-bis(p-aminophenylenesulfanyl)thianthrene (APTT) were polymerized with a sulfur-containing dianhydride, 4,4'-thiodiphthalic anhydride (TDPA), via a two-step polycondensation procedure to obtain five polyimides (PI-1 to PI-5). Flexible, tough, and transparent polyimide (PI) films with tensile strengths that ranged from 78.6 to 96.3 MPa were successfully cast from their poly(amic acid) (PAA) precursors. The PI films exhibited good thermal stability with glass transition temperatures (T_g values) as high as 265 °C and 5% weight loss temperatures > 505 °C. The high sulfur contents and flexible thioether linkages endowed the PI films with refractive indices (n_av) as high as 1.7166 at 1310 nm and birefringence (n) < 0.01. The PI-4, containing both pyridine and thioether moieties in the main chain, exhibited the best combined properties, including T_g of 265 °C, n_av of 1.6966, n of 0.0078, and optical transmittance of 88% at 450 nm at the film thickness of 10 µm.

Aromatic polyimides, which had trifluoromethyl group at 2,2'-position of the diphenyl ether, were synthesized from bis(4-amino-2-trifluoromethylphenyl)ether (1) and previously prepared tetracarboxylic dianhydrides, 3,3''',4,4'''-p-quaterphenyltetracarboxylic dianhydride (2d), 3,3'''',4,4''''-p-quinquephenyltetracarboxylic dianhydride (2e) and 3,3''''',4,4'''''-p-sexiphenyltetracarboxylic dianhydride (2f), and the properties were compared than those of corresponding polyimides from commercially available tetracarboxylic dianhydrides. The polyimides were synthesized by the conventional two-step procedure of ring-opening polyaddition in N-methyl-2-pyrrolidinone (NMP) and subsequent thermal cyclic dehydration. The polyimides were characterized by differential scanning calorimetry (DSC), thermogravimetry, and dynamic mechanical analysis (DMA). The polyimides showed excellent thermal stability, and had glass transition temperature (T_g) at 234–300 °C. The properties of polyimides were compared with those of previously prepared polyimides, which had phenyl group at 2,2'-position of the diphenyl ether, and the effect of the trifluoromethyl groups at the 2, 2'- positions of the diphenyl ether were observed in the thermal properties, solubility and optical properties of polyimides.

Bis(7-bromo-9,9-dialkylfluorenyl)diphenylsilanes with different alkyl chain lengths (C_n = 4 and 8) were synthesized in this work. Conventional 9,9-dialkyl-substituted polyfluorenes (PFs) were modified through copolymerization of the diphenylsilane-containing comonomers by the Suzuki coupling method to improve electroluminescence (EL) color purity. The PF copolymers possessed high molecular weights that were enough for film-forming ability and good solubility in various common organic solvents such as toluene. The incorporation of the diphenylsilane units suppressed effectively the PF-inherent green PL, which is undesirable for the present purpose, with a slight blue-shift of the interesting blue emission band. The results are closely related to a bent and bulky structure at the diphenylsilane units which disturb interchain stacking and a controlled conjugation length along the PF main chains. This effect was observed much more prominently in the EL spectra. Even in the di-n-butyl-substituted PF copolymer which tends to show a strong green excimer emission, the incorporation of the diphenylsilane units completely erased the green EL band. The results suggest that the PF copolymers can be a good candidate as a novel deep-blue emission layer material in EL devices.

An efficient synthetic method to control the molecular weights of poly(phenylene ether) copolymer (Allyl-PPE) with a narrow molecular weight distribution (MWD) by oxidative coupling polymerization of 2,6-dimethylphenol (DMP) and 2-allyl-6-methylphenol (AMP) has been developed. This polymerization was carried out in the presence of the di-µ-hydroxo-bis[(N,N,N',N'-tetramethylethylenediamine)-copper(II)] chloride (Cu/TMEDA) catalyst in a water droplet/toluene heterogeneous system. The polymerization conditions such as the effects of the Cu/TMEDA concentration and the amount of water were investigated, and it was found that the molecular weight of Allyl-PPE could be easily controlled by changing the concentration of Cu/TMEDA aqueous solution.

Hybrid polyimide films based on barium and titanium oxides were obtained by sol-gel technique using a poly(amic acid) containing nitrile groups and a soluble precursor of barium and titanium oxides. The poly(amic acid) was synthesized by solution polycondensation reaction of 4,4'-oxydiphthalic anhydride with 2,6-bis(3-aminophenoxy)benzonitrile. Hybrid polymer films were investigated by atomic force microscopy, scanning electron microscopy, thermogravimetric analysis and dynamic mechanical analyses. The nanoactuation properties of some hybrid polyimide films were also investigated.

Poly (m-aminophenol) (PmAP) was synthesized from m-aminophenol (mAP) by ammonium persulfate (APS) as an oxidizing agent in aqueous HCl. Polymerization conditions were optimized by varying HCl concentration, amount of mAP and APS, temperature and time. The synthesized polymers were insoluble in organic solvents even after dedoping. The polymers were characterized by UV-VIS and Fourier transform infrared spectroscopy, thermogravimetric and elemental (CHNS) analyses. Four-probe DC electrical conductivity of the pelletized polymer was measured. The spectral results clearly indicated that the ladder structure was formed during the chemical polymerization of mAP in aqueous HCl. This structure was supported by elemental analysis. Thermal stability of the undoped and in-situ HCl doped polymers was measured. The highest conductivity of the synthesized polymer pellet was 1.0 x 10^–7 S cm^–1. A polymerization mechanism was proposed.

Erratum for Ebrahim, S.M., Soliman, M.M. and Abd El-Latif, M.M. (2009). Blend of Nylon 6 and Polyaniline Doped with Sulfanilic Acid and its Schottky Diode. High Perform. Polym., first published on March 25, 2009 as doi:10.1177/0954008309103796.

A series of crosslinked sulfonated polystyrene (SPS) membranes with different degree of sulfonation (DS) were prepared in the presence of phosphorous pentoxide-methanesulfonic acid (PPMA) in the ratio of 1:10 by weight via the condensation reaction between the sulfonic acid groups and the activated hydrogen atoms of SPS. The crosslinking reaction was confirmed by ¹H-NMR and Fourier transform infrared spectrometry. In comparison with uncrosslinked SPS membrane, the crosslinked one showed much higher thermal stability as the degradation temperature increased from about 200 to 300 °C, lower but enough ion exchange capacity (IEC), lower water uptake, and lower swelling ratio. Moreover, the crosslinked SPS membranes still maintained high proton conductivity (3.3–6.1 x 10^–2 S cm^–1) and keep good shape at room temperature in 100% relative humidity. The relationships among crosslinking time, crosslinking ratio, DS and membrane properties are discussed.

Three poly(ethylene oxide) based sodium ion-conducting mixed anion systems, namely. PEO: (1 – x)NaI + xNaSCN, PEO:(1 – x)NaI + xNaCH₃COO, PEO:(1 – x) NaSCN + xNaCH₃COO have been studied. The characteristic dip in conductivity isotherm for all the three systems was observed below and above the melting of the complex. The isolated cation transference number has also been reported by the combined a.c.–d.c. technique for all three systems. The value of t_Na⁺ was found to be modified due to mixed anion doping. The detailed analysis of the systems under optical microscopy, differential scanning calorimetry, complex impedance spectroscopy and dielectric constant is discussed in the paper. It is shown that the mixed anion doping in polar-non polar combination of the anions is more effective in terms of changes in and t_Na⁺ The percentage crystallinity and dielectric constant of the medium are also correlated with the observed effect. The electrolyte dissociation model has been applied to explain the composition-dependent behavior.

The contribution of extreme ultraviolet (EUV) and vacuum ultraviolet (VUV) from a laser-sustained plasma on mass loss phenomenon of fluorinated polymer in the ground-based laser-detonation atomic oxygen (AO) beam source was evaluated. The AO beam and EUV/VUV from an oxygen plasma were separated by a high-speed chopper wheel installed in the beam source. Mass changes of fluorinated polymer and polyimide were measured from the frequency shift of the quartz crystal microbalances during the beam exposures. It has been made clear that the fluorinated polymer is eroded by EUV/VUV exposure alone. In contrast, no erosion was detected for polyimide by EUV/VUV alone. The AO-induced erosion was measured for both materials even without EUV/VUV exposure. However, no strong synergistic effect was observed for the fluorinated polymer even under the simultaneous exposure condition of AO and EUV/VUV. Similar results were observed even in the simultaneous exposure condition of AO (without EUV/VUV from the laser plasma) and VUV from the 172 nm excimer lamp and D₂ lamp. These experimental results suggest that the primary origin of the accelerated erosion of fluorinated polymer observed in the laser detonation AO source is not EUV/VUV from the laser-sustained plasma.

Well-defined antibacterial block copolymers of 4-vinyl pyridine (4VP) and pentachlorophenyl acrylate (PCPA) (P(4VP-b-PCPA)) were prepared via reversible addition–fragmentation chain transfer (RAFT) polymerization. Electrospinning of the P(4VP-b-PCPA) from a solution in mixed tetrahydrofuran and dimethylformamide gave rise to fibers with diameters in the range of 0.5–4.0 µm. The quaternary ammonium salts (QASs) were generated by N-alkylation of pyridine groups of P4VP block and chloro-aromatic compounds of PPCPA block (or self-quaternization of P(4VP-b-PCPA)). The self-quaternization of P(4VP-b-PCPA) nanofibers was studied by X-ray photoelectron spectroscopy. Attributable to the hydrophobicity of the PPCPA blocks and the electrostatic interaction of QASs generated from the self-quaternization of P(4VP-b-PCPA), the resulting nanofibers exhibit a high antibacterial efficiency. The antibacterial effect of the P(4VP-b-PCPA) nanofibers was assayed using Escherichia coli and Staphylococcus aureus cultures. It was found that 99.6% of E. coli and 99.1% S. aureus were killed after being in contact with 50 mg nanofibers in 10 min. The permanence of antibacterial activity of the self-quaternized P(4VP-b-PCPA) nanofibers was also demonstrated in repeat application.

Five polytriazole resins, TAMTMB-BPF, TAMTMB-BPA, TAMTMB-BPK, TAMTMB-BPE, and TAMTMB-BPR, were prepared from 1,3,5-tris(azidomethyl)-2,4,6-trimethylbenzene (TAMTMB) and dipropargyl ethers of hexafluorobisphenol A (BPF), bisphenol A (BPA), 4,4'-dihydroxybenzophenone (BPK), 4,4'-dihydroxydiphenyl ether (BPE), and resorcinol (BPR), respectively. The resins were characterized by Fourier transform infrared spectrometry, differential scanning calorimetry, dynamic mechanical analysis, and thermogravimetric analysis. The results illustrate that the structures of dipropargyl ethers had no obvious effect on the curing behavior of the polytriazole resins and the thermal stability of the cured resins. The polytriazole resins could be cured at 80 °C and further post-cured at higher temperature. The cured resins had a thermal decomposition temperature T_d5 near 360 °C. However, the structural units of the polytriazole resins influenced the glass transition temperature T_g, dielectric properties, and mechanical properties of the cured resins to some extent. The cured TAMTMB-BPF resin had the highest T_g (226 °C) and best dielectric properties among the resins, whereas the cured TAMTMB-BPR resin showed the highest flexural strength of 200.6 MPa.

Epoxidized soybean oil at various concentrations was cured with amine curing agent. The prepared matrices were chemically modified with three types of bismaleimides, namely N,N'-bismaleimido-4,4'-diphenylmethane (BMI-1), 1,3-bis(maleimido)benzene (BMI-2) and 3,3'-bis(maleimidophenyl)phenylphosphine oxide (BMI-3). The interpenetrating networks thus developed were characterized for glass transition temperature, thermal stability, dynamic mechanical analysis, heat distortion temperature, flame retardancy and water absorption behavior. The incorporation of bismaleimides in the soy-based epoxy matrices significantly enhanced thermal stability and flame retardancy. The excellent flame retardant properties of the BMI-3 incorporated system were also demonstrated by high char yield and high limiting oxygen index. Dynamic mechanical analysis studies showed that the storage modulus increased with the increase in the concentration of bismaleimides and a reduction in the tan value for the bismaleimide-modified, 30 wt.% soy-based epoxy system due to enhanced cross-linking density and rigidity.

Real-time measurement of the erosion rate of a commercially available Si-containing polyimide (BSF30) under hyperthermal atomic oxygen (AO) beam exposure condition, which simulates the AO environment in low Earth orbit (LEO), was performed. It was found that the erosion rate of BSF30 decreased with increasing AO fluence and it reached as low as 4% of the standard PMDA-ODA polyimide. X-ray photoelectron spectroscopy confirmed that the surface of AO-exposed BSF30 was covered by a SiO₂ layer which functioned as a protective coating. In contrast, an SiO₂ surface layer thick enough to protect bulk BSF30 was not formed by thermal AO, which was generated by vacuum ultraviolet exposure in an O₂ atmosphere. Exposure to hyperthermal AO collision in LEO can also form an SiO₂ layer which enables the surface to be self-healing and is desirable for a polyimide that would be used in LEO.

Two aromatic isophthalic polyesters and three copolyesters were synthesized by interfacial polycondensation using 2,4-dihydroxybenzophenone (2,4-DBP) and 4,4'-(hexafluoroisopropylidene)diphenol (HFD) with isophthaloyl chloride (ISO). All polymers were soluble in common chlorinated solvents. These aromatic polyesters and copolyesters were characterized by infrared and nuclear magnetic resonance spectroscopy. Their thermal, dynamic mechanical and physical properties were also determined. The glass transition temperature, onset of decomposition, and thermal stability of the homopolymer, poly(hexafluoroisopropilydene)isophthalate (HFD/ISO), were higher than those of homopolymer poly(2,4-benzophenone)isophthalate (2,4-DBP/ISO). The thermal properties of the copolyesters HFD/ISO-co-DBP/ISO depend upon the amounts of HFD/ISO moiety present in the copolymer. Physical properties of the copolyesters were intermediate between those of the homopolyesters and depend upon the concentration of comonomers present in the copolyester..

Aromatic polyesters and poly(ester-imide)s based on bisphenol-A derivatives were prepared by solution polycondensation at high temperature of three diols with an aromatic diacide chloride containing two preformed ester groups, namely terephthaloyl-bis-(4-oxybenzoylchloride) or two diacide chlorides containing preformed imide rings, namely 4-chloroformyl-N(p-chloroformylphenyl)-phthalimide and 2,2-bis[N-(4-chloroformylphenyl)phthalimidyl] hexafluoropropane. The polymers were easily soluble in polar organic solvents, such as N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide and chloroform. They showed high thermal stability, the decomposition temperature being above 320 °C and the glass transition temperature in the range 92–196 °C. Some of the polymers exhibited thermotropic liquid crystalline behavior.

Solid-state microwave synthesis was found to give a simple, rapid and economical route to prepare different kinds of materials. In this investigation, a new method for solid-state polymerization reaction of 4-phenylurazole (PHU) and 4-(4-methoxyphenyl)urazole (MPU) with different diisocyanates was developed under microwave irradiation. The reaction of PHU and MPU with hexamethylene diisocyanate, isophorone diisocyanate, and tolulyene-2,4-diisocyanate were performed under solid-state conditions in the presence or absence of dibutyltin dilaurate as a catalyst. The resulting polyureas showed good yields and moderate inherent viscosities ranging of 0.20 to 0.34 dL g^–1 in N,N-dimethylformamide at 30 °C. All of the aforementioned polymers were characterized by ¹H-NMR, FT-IR spectroscopy and thermogravimetric analysis. This method was compared with solid-state polymerization under high temperature conditions and also with the solution polymerization reaction in N,N-dimethylacetamide. Under microwave-assisted, solid-state conditions, higher yields and inherent viscosities were obtained. In addition in this method we do not need to use any solvents and the polymerization reaction can be classified as a green, cost-effective and environmentally friendly method.

In order to further improve both processability of imide oligomers containing pendent or/and terminal phenylethynyl groups and their cured T_g values without sacrificing mechanical properties, isomeric dianhydrides, 2,2',3,3'-biphenyltetracarboxylic dianhydride (3,3'-BPDA) or 2,3',3,4'-biphenyl tetracarboxylic dianhydride (3,4'-BPDA), were introduced into main chain. The rigid and bent structure of the isomeric BPDAs can provide a good combination of melt flow while maintaining a high T_g. Phenylethynyl containing oligoimides were prepared from the reaction of isomeric dianhydrides (3,3'-BPDA, 3,4'-BPDA and 4,4'-BPDA), 4,4'-oxydianiline (4,4'-ODA), 3,5-diamino-4'-phenylethynyl benzophenone (DPEB) and 4-phenylethynylphthalic anhydride (4-PEPA) or phthalic anhydride (PA) at an approximate number average molecular weight of 2500 and 5000 g mol^–1. The imide oligomers from 3,3'-BPDA and 3,4'-BPDA exhibited good processability. The 3,3'-BPDA-based imide oligomers exhibited slightly lower melt viscosity and the cured resins exhibited similar T_g values compared with those from 3,4'-BPDA. OI-7 and OI-8 each with a molecular weight of 2500 g mol^–1 had lower melt viscosities of 25 Pa s (342 °C) and 178 Pa s (344 °C) and higher cured T_g at 367 °C and 365 °C. The cured films from OI-7, OI-8 showed good tensile properties and the elongations at break were around 10%. The neat resins from OI-7 and OI-8 had higher compressive strengths of 200 and 190 MPa. G827/OI-7 and G827/OI-8 exhibited comparable mechanical properities: flexural strengths of 1714 and 1826 MPa, flexural modulus of 130 and 124 GPa, and interlayer shear strengths of 95 and 101 MPa, respectively.

In the present study, the synthesis of high molecular weight polyimides was conducted in water using microwave irradiation. High molecular weight polymers were obtained after only 5~min of reaction time. The influence of different experimental parameters is discussed in connection with a thorough characterization of the synthesized polymers. From these polymers, self-supporting films were obtained.

The porous structure and shape memory effect (SME) were studied for a porous shape memory polymer (SMP) with varying densities, two different thicknesses and the addition of varying weight percentages of organoclay. In order to alter the density of the SMP, a batch processing technique was utilized in which the saturation pressure and foaming time were varied and saturation time and foaming temperature were kept constant. The change in density as the effect of reducing the thickness of the SMP on the time response of the SME was investigated. In addition, the effects of the change in density, change in thickness or the addition of organoclay on the recovery force of the SMP were elucidated. With the objective of designing an SMP to be used as an actuator, response time, recovery force and weight savings are critical parameters.

The study was concerned with the synthesis and characterization of a silsesquioxane-based hybrid nanocomposite with self-assembling properties intended for monumental porous limestone conservation. Radical polymerization of 3-(trimethoxysilyl)propyl methacrylate in the presence of a primary amine surfactant yielded a new type of hybrid nanocomposite, in which silica was dispersed as domains with typical sizes in the nanometer range. The self-assembling properties of the synthesized composite have been ascribed to the supramolecular assembling abilities of the surfactant, as well as to the combination of linear, ladder, and cage-like fragments of silsesquioxane type. This new sol–gel approach, in which the surfactant makes the pore size of the network more coarse and uniform, avoids cracking while drying inside the stone and thus provides an effective alternative for porous limestone conservation.

We investigated by attenuated total reflection Fourier infrared spectroscopy the chemical behavior of macromolecules on the surface of polyurethane microporous film doped with silver nanoparticles at temperatures between 25 and 200°C. Silver nanoparticles interact with the urethane group and form a urethane-silver-urethane structure with a specific surface configuration and a higher resistance to temperature. Chemical transformations of the macromolecules on the surface of polyurethane film depend on both the silver nanoparticles concentration and temperature.

A new monomer containing naphthalene, 2,6-bis(β-naphthoxy)benzonitrile (BNOBN) was synthesized by reaction of β-naphthol with 2,6-difluorobenzonitrile in N-methyl-2-pyrrolidone (NMP) in the presence of KOH and K₂CO₃. Novel copolymers of poly(ether ketone ketone) and poly(ether ether ketone ketone) containing naphthalene moieties and pendant cyano groups were prepared by electrophilic Friedel–Crafts solution copolycondensation of terephthaloyl chloride (TPC) with varying mole proportions of diphenyl ether and 2,6-bis(β-naphthoxy)benzonitrile (BNOBN) using 1,2-dichloroethane as solvent and NMP as Lewis base in the presence of anhydrous AlCl₃. The crystallinity and melting temperatures of the polymers were found to decrease as the concentration of BNOBN in the polymer increased, whereas the glass transition temperatures of the polymers increased as the concentration of BNOBN in the polymer increased. The copolymers with 20–25 mol% BNOBN had high T_g values of 182–184 °C; moderate T_m values of 324–335 °C; tensile strengths of 101.8–103.2 MPa, Young's moduli of 3.14–3.23 GPa, and elongations at break of 15–18%. The copolymers exhibited outstanding thermal stability and good resistance to organic solvents, acidity and alkali.

The electrical conductivity of cross-linked lanthanum(III)- and cerium(III)-alginate complexes in the form of circular discs has been studied as a function of temperature. The Arrhenius plots of log versus 1/T showed a sharp increase in the electrical conductivity values at elevated temperatures, whereas no changes in values were observed at lower temperatures (< 450 K). This behavior was explained by the degradation of the complexes at higher temperatures to give rise to metal oxide products at the final stages. The heterogeneous chemical equilibrium for exchange of La³⁺ and Ce³⁺ metal ions by H⁺ ions has been investigated complexometrically and titrimetrically. The X-ray diffraction pattern indicated that these complexes are amorphous in nature. Infrared absorption spectra indicated the presence of chelated La³⁺ and Ce³⁺ metal ions with alginate macromolecular chains. A geometrical structure for chelation of lanthanum(III) and cerium(III) to the carboxylate and hydroxyl functional groups of the alginate macromolecule is suggested and discussed in terms of complex stability.

The polymeric ligand was synthesized by condensation of 2-hydroxy-4-ethoxyacetophenone with 1,4-butane diol in presence of polyphosphoric acid as a catalyst at 145 ºC for 10 h. The synthesized polymeric ligand was used to synthesize the corresponding polychelates with 4f-block elements. The polymeric ligand and its polychelates were characterized by elemental analyses, electronic spectra, magnetic susceptibilities, Fourier transform infrared spectroscopy, nuclear magnetic resonance and thermogravimetric analyses. Morphological study of the polymeric ligand and polychelates were carried out by scanning electron microscopy. Number average molecular weight (M_n) was determined by a vapor pressure osmometry method. Antimicrobial activity for all polychelates and catalytic activity of selected polychelates in organic synthesis were examined. It was observed from the study that the polychelates acted as an efficient catalysts and antimicrobial agents.

Organophilic montmorillonite clay – unsaturated polyester (UP) and vinyl ester oligomer (VEO) – unsaturated polyester nanocomposites were prepared and the formation of nanocomposites was evaluated by X-ray diffraction (XRD), dynamic mechanical analysis (DMA) and scanning electron microscopy (SEM). The VEO was prepared by reactingcommercially available epoxy resin LY556 and acrylic acid and was used as a toughening agent for unsaturated polyester resin. Organoclay-filled hybrid VEO–UP matrices, developed in the form of castings, were characterized for their thermal and mechanical properties. Dynamic mechanical measurements indicated the presence of higher crosslink density for the clay-filled systems than unfilled systems. X-ray diffraction analysis infers the intercalation of the polymer molecules between the clay layers which in turn restricts the mobility of polymer in the vicinity of clay layers. A shift in T_g towards lower temperature was observed for nanocomposites. Significant improvement in the mechanical properties was also observed in the case of nanocomposites when compared with neat resin matrix.

Benzophenone-type unsymmetrical substituted aromatic diamines of general formula

were prepared starting with p-nitrobenzoyl chloride and substituted benzenes. Interaction of the diamines obtained with aromatic tetracarboxylic acids dianhydrides under the conditions of high-temperature solution polycyclocondensation in m-cresol led to the formation of new high molecular weight organosoluble polyimides.

Five new co-poly(imide siloxane)s have been prepared by reacting two diamine monomers 9, 10-bis [3'-trifluoromethyl-4' (4-aminobenzoxy) benzyl] anthracene (TFAA) and amino-propyl terminated polydimethylsiloxane (APPS) together with different commercially available dianhydrides like benzene-1,2,4,5-tetracarboxylic dianhydride (PMDA), 4,4'-(hexafluoro-isopropylidene)diphthalic anhydride (6FDA), 4,4'-oxydiphthalic anhydride (ODPA), 4,4'-(4,4'-Isopropylidenediphenoxy)bis(phthalic anhydride) (BPADA) and benzophenone-3,3',4,4'-tetracarboxylic dianhydride (BTDA). In each case the siloxane loading was adjusted to about 40 wt.% in the respective copolymers. The polymers were either synthesized by the one-pot solution imidization method or by the thermal imidization route. The synthesized polymers show predominantly good solubility in different organic solvents. The resulting polymers have been characterized by gel permeation chromatography, infrared and nuclear magnetic resonance techniques. These polyimides show good thermal stability with decomposition temperature (5% weight loss) up to 463 ºC in nitrogen. Transparent thin films of these polyimides exhibit tensile strengths up to 31 MPa, a modulus of elasticity up to 0.63 GPa and elongation at break up to 110%.

For co-polyimides (PIs) of mellitic acid dianhydride, 1,3-aminophenoxybenzene and 4,4'-oxydiphthalic anhydride, Zr-pendent group content could be increased to 50% (mol) improving atomic oxygen (AO) resistance while retaining good film properties. Spectral data are consistent with expected structures. Intrinsic viscosities of 0.54–0.60 dL g^–1 and average molecular weights of 111 000–122 000 g mol^–1 estimated from gel permeation chromatography confirm the polymeric nature of co-polyamic acid precursors. Nuclear magnetic resonance integrations and amounts of thermogravimetric analysis residue verify pendent group concentrations. Increasing Zr-pendent group concentration from 10 to 50% (mol) caused glass transition temperatures to increase (198–245 °C), decomposition temperatures to decrease (518–455 °C), and the number of film layers able to be fabricated prior to crack formation to decrease (10 to 8). These numbers of layers were much higher than those for other PIs with comparable Zr-pendent group concentrations. Increased pendent group concentration caused the amount of protective oxide layer formed upon AO exposure to increase.

The influence of the ratio of epoxy (EP) to dicyclopentadiene bisphenol cyanate ester (DCPDCE) on the curing behavior of EP/DCPDCE system was studied using differential scanning calorimetry and Fourier transform infrared spectroscopy. The conversion of –OCN groups and the formation of the reaction products in the different EP/DCPDCE systems and at different curing steps were determined. The results show that the epoxy resin has both a catalytic effect and a dilution effect on the trimerization reaction of –OCN groups. These two effects reach an approximate balance when the content of epoxy resin in the EP/DCPDCE system is 15 wt.%. In addition, the epoxy resin can improve the final conversion of –OCN groups, and the initial amount of epoxy resin has a significant influence on the final structure of the co-polymers.

The tensile properties of sulfonated polyoxadiazoles were studied as a function of molecular weight and sulfonation level. All sulfonated polyoxadiazoles synthesized through a polycondensation reaction of the hydrazine sulphate salt and a dicarboxylic acid in poly(phosphoric acid) exhibit rigid-ductile behavior with high Young's modulus (3–4 GPa) and with larger elongations at break (up to 120%). Sulfonated polyoxadiazoles with maximum reproducible tensile strength (190 6.9 MPa) could be synthesized in the frame of time of 4–5 h.

Thermoplastic polyurethanes (PU) were prepared from 4,4'-diphenyl methane diisocyanate (MDI), polyether polyol and 1,4 butane diol with and without a hindered amine light stabilizer (Tinuvin^®-123) and UV absorber (Tinuvin^®-400). The accelerated hygrothermal and UV aging were performed at different humidity and aging temperatures for 720, 1440, and 2160 h of exposure, in a Thermotron environmental chamber and QUV chamber, respectively. Fourier transform infrared spectroscopy was used to evaluate the structural changes during aging. The thermal transition for PU, studied by differential scanning calorimetry showed a marginal structural damage after hygrothermal aging. After only 720 h of UV exposure, the neat PU showed a noticeable change in the chemical structure; however, the stabilized one showed almost no change. Tensile strength for the neat PU deteriorated by about 47% after 2160 h of UV exposure; however, the stabilized polyurethane maintained its almost original strength (i.e., 83% retention) after the whole exposure time. The acceleration factor was found to be 6 and the predicted life time for the stabilized polyurethane was about 6 years.

A completely amorphous polyimide (PI) derived from 2,3,3',4'-biphenyltetracarboxylic dianhydride (a-BPDA) with 4,4'-oxydianiline (4,4'-ODA) (i.e. a-BPDA/ODA) was used as a matrix polymer for a rod-like polyimide structure derived from pyromellitic dianhydride (PMDA) with p-phenylenediamine (PDA) (i.e. PMDA/PDA) to improve the toughness without sacrificing its ultra-low coefficient of thermal expansion (CTE) characteristics. A matrix effect of a-BPDA/ODA was investigated by comparing with an isomer PI system, s-BPDA/ODA (s-BPDA: 3,3',4,4'-biphenyltetracarboxylic dianhydride). Neither of the PMDA/PDA-based blend systems with a minor fraction of these flexible PIs showed any distinct glass transitions during dynamic mechanical thermal analysis. The unique fluorescence behavior of perylenetetracarboxydiimide (PEDI), which became almost non-fluorescent by intimate intermolecular contact with the PMDA/PDA chains, was applied to study the miscibility of the PMDA/PDA-based blend systems. For this purpose, a- and s-BPDA/ODA was labeled by copolymerization using a trace amount of difunctional PEDI. The results revealed that the a-BPDA/ODA-containing blend system was miscible over the entire blend composition whereas the s-BPDA/ODA-containing counterpart was essentially immiscible. The a-BPDA/ODA was much more effective as a flexible component than s-BPDA/ODA for reducing the crystallinity of PMDA/PDA and, as a result, significantly improved the film toughness. Blending of only small amounts of a-BPDA/ODA (5–10 wt.%) into PMDA/PDA caused an unexpected further decrease in the ultra-low CTE (2.8 ppm/K) of homo PMDA/PDA film. A mechanism is proposed to reasonably explain the results obtained in the present study. The blend system composed of PMDA/PDA (90 wt/%) and a-BPDA/ODA (10 wt.%) achieved an ultra-low CTE of 0.9 ppm K^–1 in addition to sufficient film flexibility.

A series of poly(ether sulfone)s copolymers (BP-COPPESs) based on phthalazinone and biphenyl moieties were synthesized by nucleophilic displacement reaction from 4-(4-hydroxyphenyl)-2,3-phthalazin-1-one (DHPZ), biphenol (BP) and bis(4-chlorophenyl) sulfone (BCS). The experimental results indicated that the higher initial concentration of the polymerization reaction resulted in lower cyclic content and narrower molecular weight distribution of resultant copolymers. Moreover, the molecular weight decreased with increasing content of phthalazinone moiety of the main chain. These copolymers showed high glass transition temperatures (T_g values) together with superior thermal properties. These copolymers were soluble in various aprotic solvents and were amorphous as evidenced by wide-angle X-ray diffraction. The molecular weights of BP-COPPES64 (60% phthalazinone moiety) could be controlled by utilizing excess molar content of BCS monomer. The rheological property test of copolymers indicated that the torque values decreased with increasing biphenyl group and ether linkage content.