Synthesis,optical, electrochemical,and thermal stability properties of poly(azomethine-urethane)s

In this study, the novel low band gap and thermally stable poly(azomethine-urethane)s (PAMUs) were synthesized to investigate aliphatic and aromatic group effects on some physical properties such as thermal stability, optical and electrochemical properties. For this reason, we firstly synthesized the new Schiff bases via condensation reaction of 5-nitrovanilin with aromatic and aliphatic diamines. Then, these monomers were converted to PAMUs derivatives by the step-polymerization reaction with aromatic and aliphatic diisocyanates. The structures of the compounds were confirmed by FT-IR, UV–vis, ¹H NMR, and ¹³C NMR techniques. The molecular weight distribution parameters of the compounds were determined by the size exclusion chromatography (SEC). The compounds were also characterized by solubility tests, TG–DTA, and DSC techniques. Cyclic voltammetry (CV) measurements were carried out and HOMO–LUMO energy levels and electrochemical band gaps (E^′g${E^{\prime }}_g$) were calculated from their absorption edges. Additionally, optical band gaps (E_g) were determined by using UV–vis spectra of the materials. Fluorescence measurements were carried out in THF, DMF, and DMSO solutions to determine the optimum concentrations and the maximal emission and excitation intensities.     

Influence of carbon nanotubes on the thermal, electrical and mechanical properties of poly(ether ether ketone)/glass fiber laminates

Novel poly(ether ether ketone) (PEEK)/single-walled carbon nanotube (SWCNT)/glass fiber laminates incorporating polysulfone as a compatibilizing agent were fabricated by melt-blending and hot-press processing. Their morphology, mechanical, thermal and electrical properties were investigated and compared with the behavior of similar non-compatibilized composites. Scanning electron micrographs demonstrated better SWCNT dispersion for samples with polysulfone. Thermogravimetric analysis indicated a remarkable improvement in the thermal stability of PEEK/glass fiber by the incorporation of SWCNTs wrapped in the compatibilizer, ascribed to a significant thermal conductivity enhancement. Differential scanning calorimetry showed a decrease in the crystallization temperature and crystallinity of the polymer with the addition of both wrapped and non-wrapped SWCNTs. The laminates exhibit anisotropic electrical behavior; their conductivity out-of-plane is lower than that in-plane. Dynamic mechanical studies revealed an increase in the storage modulus and glass transition temperature in the presence of polysulfone. Mechanical tests demonstrated significant enhancements in stiffness, strength and toughness by the incorporation of wrapped nanofillers, whilst the mechanical properties of non-compatibilized composites only improved marginally. Samples with laser-grown SWCNTs exhibit enhanced overall performance. This investigation confirms that SWCNT-reinforced PEEK/glass fiber compatibilized composites possess excellent potential to be used as multifunctional engineering materials in industrial applications.     

Copolymers of poly(arylene sulfide sulfone)/poly(ether sulfone): Synthesis,structure, and rheology properties

In order to overcome the poor flowability of poly(arylene sulfide sulfone) (PASS), we introduced ether bonds into the polymer main chain. A series poly(arylene ether sulfide sulfone) copolymers (PAESS) containing different proportion of ether bonds were synthesized with 4,4′‐dichlorodiphenyl sulfone (DCDPS), sodium sulfide (Na₂S·xH₂O), and 4,4′‐dihydroxydiphenyl ether (DHDPE). The copolymers were characterized by Fourier transform infrared (FTIR), ¹H‐nuclear magnetic resonance (NMR), differential scanning calorimetry, dynamic mechanical analysis (DMA), and rheometer. The results of FTIR and ¹H‐NMR indicate the copolymers are synthesized successfully. PAESS were found to have excellent thermal properties with glass transition temperature (T_g) of 175.7–219.1 °C and 5% weight lost temperature were all above 420 °C. The tensile and DMA test indicates that these resultant copolymers have good mechanical properties with tensile strength of 60 MPa and storage modulus of 1.5 GPa. From the results of rheology properties testing, we found that the melt stability and melt flowability of PASS were improved distinctly from 25,470 Pa s down to 355 Pa s with the incorporation of ether bonds. That will be quite beneficial to the processing of PASS, especially for the thermoforming of precision products. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46534.     

Synthesis, optical and electrochemical properties of new hyperbranched poly(triphenylamine amide)s

A new triphenylamine-containing AB₂ type monomer with one carboxylic acid and two amino groups, 4-(bis(4-aminophenyl)amino)benzoic acid (3), was synthesized and used for the preparation of hyperbranched poly(triphenylamine amide)s. The self-polycondensation of the AB₂ monomer (3) afforded hyperbranched poly(triphenylamine amide) with amino end groups. The molecular weight of the hyperbranched poly(triphenylamine amide) was 21,000 Da determined by light scattering. End-capped hyperbranched polyamides were isolated by the chemical modification of unreacted amino groups with various acid chlorides. All the hyperbranched poly(triphenylamine amide)s exhibit excellent solubility in organic solvents such as NMP, DMF, DMSO, and DMAc at room temperature. The viscosities of hyperbranched poly(triphenylamine amide)s are as low as about 0.15 dL/g due to their dendritic structures. Poly(triphenylamine amide)s end-capped with rigid benzene ring have higher thermal stability than those with amino or aliphatic end groups. The photoluminescence of the hyperbranched polyamides is blue-yellow emissions around 430-510 nm. The energy gaps of the hyperbranched poly(triphenylamine amide)s with different end groups are about 2.93 eV and are independent on the end groups, but the HOMO and LUMO energy levels are dependent on the end groups.     

Synthesis, characterization and optical properties of fluorinated poly(aryl ether)s containing phthalazinone moieties

A series of novel fluorinated poly(aryl ether)s containing phthalazinone moieties (FPPEs) have been prepared by a modified synthetic procedure for optical waveguide applications. The obtained random copolymers exhibited excellent solubility in polar organic solvents, high glass transition temperatures (T_gs: 185-269 °C), good thermal stabilities (the temperatures of 1% weight loss: 487-510 °C) and good optical properties. By adjusting the feed ratio of the reactants, the refractive indices of TE and TM modes (at 1550 nm) could be well controlled in the range of 1.575-1.498 and 1.552-1.484, respectively. The optical losses of the FPPEs exhibited relatively low values (less than 0.27 dB/cm at 1310 nm). Additionally, the thermo-optic coefficient (dn/dT) values of the FPPEs at 1310 nm and 1550 nm (TE mode) ranged from −0.97 × 10⁻⁴ °C to −1.33 × 10⁻⁴ °C and from −0.96 × 10⁻⁴ °C to −1.29 × 10⁻⁴ °C, respectively.     

Crystallization,morphology, and electrical properties of bio‐based poly(trimethylene terephthalate)/poly(ether esteramide)/ionomer blends

Bio‐based poly(trimethylene terephthalate) (PTT) and poly(ether esteramide) (PEEA) blends were prepared by melt processing with varying weight ratios (0–20 wt %) of ionomers such as lithium‐neutralized poly(ethylene‐co‐methacrylic acid) copolymer (EMAA‐Li) and sodium‐neutralized poly(ethylene‐co‐methacrylic acid) copolymer (EMAA‐Na). The blends were characterized by differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), polarized light microscopy (PLM), and transmission electron microscopy (TEM). DSC and PLM results showed that EMAA‐Na increased the crystallization rate for PTT significantly, whereas EMAA‐Li did not enhance the crystallization rate at all. Specific interactions between PEEA and ionomers were confirmed by DSC and TEM. Electrostatic performance was also investigated for those PTT blends because PEEA is known as an ion‐conductive polymer. Here, we confirmed that both sodium and lithium ionomers work as a synergist to enhance the static decay performance of PTT/PEEA blends. Morphological study of these ternary blends systems was conducted by TEM. Dispersed ionomer domains were encapsulated by PEEA, which increases the interfacial surface area between PEEA and the PTT matrix. This encapsulation effect explains the unexpected synergy for the static dissipation performance on addition of ionomers to PTT/PEEA blends. This core–shell morphology can be predicted by calculating spreading coefficient for the ternary blends. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Novel ternary poly(vinyl pyrrolidone)/poly(amide-imide)/ZnO nanocomposite: Synthesis,characterization, thermal and optical performance

The present work describes the synthesis and properties of polymer composites based on poly(vinyl pyrrolidone) (PVP) as polymer shell and poly(amide-imide)(PAI)/ZnO nanocomposite (ZNC) as efficient filler. At first, the alanine amino acid containing dicarboxylic acid was grafted on the surface of ZnO NPs. Then, modified ZnO (12 wt%) was incorporated into the PAI matrix under ultrasonic irradiations. The obtained hybrid ZNC showed high thermal stability and the size of the NPs in the TEM image of ZNC was about 31 nm. Secondly, PVP NCs with different ZNC loadings such as 2, 4 and 6 wt% were prepared via ultrasonication. Transmission electron microscopy (TEM) observations showed that the ZnO NPs were uniformly and highly dispersed in the PVP matrix. The UV–vis results exposed that the high UV-shielding efficiency of the obtained composites. Thermal analysis represented that the onset decomposition temperatures of the obtained PVPNCs had remarkable increasing in compared to the neat PVP due to the presence of both ZnO NPs and PAI.     

Studies on the mechanical,thermal, and morphological properties of poly(ether ether ketone)/poly(ether sulfone)/barium titanate nanocomposites: Correlation of experimental results with theoretical predictive models

In this study, mechanical, thermal, and morphological properties of the nanocomposites fabricated with the optimized blend of poly(ether ether ketone) (PEEK) and poly(ether sulfone) (PES) incorporated with nanobarium titanate (BT) were investigated. The optimized blend was based on the mechanical and thermal properties of the PEEK and PES in the ratio of 75 : 25 wt %. Nanoparticles were incorporated into the optimized blend with the help of twin‐screw extruder. The concentration of nano‐BT was varied from 2 to 6 wt % (0.41–1.28 vol %). With the increase in the nanosized BT concentrations, the tensile strength, tensile modulus, and elongation at break increased, whereas the crystallinity of the nanocomposites calculated by using differential scanning calorimetry method was found to decrease marginally. Morphological studies were carried out using scanning electron microscopy. The nanocomposites were evaluated by using theoretical predictive models according to “Pukanszky model” applicable to tensile strength and “Takayanagi's model” and “Guth and Smallwood model” applicable to tensile modulus. Upper and lower boundary of Hashin–Shtrikman model as well as Paul's model, applicable to tensile modulus, were also used to compare the experimental data. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis and properties of novel poly(aryl ether ketone)s containing imide linkages in the main chains

A new monomer containing imide linkages, bis[4-(p-phenoxybenzoyl)-1,2-benzenedioyl]-N,N,N′,N′-4,4′-diaminodiphenyl ether (BPBDADPE), was prepared by the Friedel–Crafts reaction of bis(4-chloroformyl-1,2-benzenedioyl)-N,N,N′,N′-4,4′-diaminodiphenyl ether (BCBDADPE) with diphenyl ether (DPE). Novel poly(aryl ether ketone)s containing imide linkages in the main chains (PEK-I) were synthesized by electrophilic Friedel–Crafts solution copolycondensation of terephthaloyl chloride (TPC) with a mixture of DPE and BPBDADPE. The polymers were characterized by different physico-chemical techniques. The polymers with 10–40 mol% BPBDADPE are semicrystalline and had increased T _gs over commercially available poly(ether ether ketone) (PEEK) and poly(ether ketone ketone) (PEKK) (70/30) due to the incorporation of imide linkages in the main chains. The polymers IV and V with 30–40 mol% BPBDADPE had not only high T _gs of 182–183 °C, but also moderate T _ms of 341–343 °C, having good potential for melt processing and exhibited high thermal stability and good resistance to common organic solvents.     

Synthesis,characterization, and properties of novel poly(ether urea)s

Two diamines, 2,6‐bis(4‐aminophenoxy)pyridine and 2,6‐bis(5‐amino‐1‐naphenoxy)pyridine, were prepared through the nucleophilic aromatic substitution reaction of 4‐aminophenol and 5‐amino‐1‐naphthol, respectively, with 2,6‐dichloropyridine. Poly(ether urea)s were synthesized through the polyaddition reactions of these diamines with aromatic, semiaromatic, and cycloaliphatic diisocyanates. All the monomers and polymers were fully characterized, and physical properties of the polymers, including the thermal behavior, thermal stability, solubility, and solution viscosity, were studied. The polyureas showed improved thermal stability. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 961–965, 2004     

Synthesis,properties, and gas permeation performance of cardo poly(arylene ether sulfone)s containing phthalimide side groups

Novel bisphenol monomers ( 1a‐d ) containing phthalimide groups were synthesized by the reaction of phenolphthalein with ammonia, methylamine, aniline, and 4‐tert‐butylanilne, respectively. A series of cardo poly(arylene ether sulfone)s was synthesized via aromatic nucleophilic substitution of 1a‐d with dichlorodiphenylsulfone, and characterized in terms of thermal, mechanical and gas transport properties to H₂, O₂, N₂, and CO₂. The polymers showed high glass transition temperature in the range 230–296°C, good solubility in polar solvents as well as excellent thermal stability with 5% weight loss above 410°C. The most permeable membrane studied showed permeability coefficients of 1.78 barrers to O₂ and 13.80 barrers to CO₂, with ideal selectivity factors of 4.24 for O₂/N₂ pair and 28.75 for CO₂/CH₄ pair. Furthermore, the structure–property relationship among these cardo poly(arylene ether sulfone)s had been discussed on solubility, thermal stability, mechanical, and gas permeation properties. The results indicated that introducing 4‐tert‐butylphenyl group improved the gas permeability of polymers evidently. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Synthesis, characterization, and thermal properties of poly(siloxane-carborane)s

Three exactly alternating carborane-siloxane polymers P1, P2, and P3, have been synthesized by the polycondensation of 1,7-bis(dimethylhydroxylsilyl)-m-carborane and cyclotrisilazanes in the presence of (NH₄)₂SO₄. The reaction shows a new and convenient synthesis of poly(carborane-siloxane)s, and the first example of stoichiometric polycondensation of cyclosilazanes with diols. The new polymers P2 and P3 could be converted into thermosets at elevated temperature through the cross-linking of pendant vinyl groups. The structures of the polymers were fully characterized. Thermogravimetric analysis (TGA) showed the superior thermal stability of the polymers and thermosets, with their char yields of over 83% both in air (800 °C) and nitrogen (1000 °C). The microstructure of the chars was studied by scanning electron microscopy (SEM). It was found that the cross-linking of vinyl groups helped in enhancing the thermal stabilities of the polymers and keeping the integrity of the chars. The results suggest their potential utility under severe thermal and/or thermo-oxidative conditions.     

Synthesis, characterization and optical properties of cross-linkable poly(phthalazinone ether ketone sulfone)

Cross-linkable poly(phthalazinone ether ketone sulfone) bearing tetrafluorostyrene groups (PPEKS-FSt) has been prepared by copolycondensation reaction for optical waveguide applications. The resulting amorphous polymer exhibits good solubility in some common polar organic solvents (e.g., N,N′-dimethylacetamide, N-methyl-2-pyrrolidinone, chloroform) at room temperature, and can be easily spin-coated into thin films with good optical quality. The glass transition temperature (T_g) and the temperature of 1% weight loss (1% T_d) are 261 °C and 494 °C, respectively, which could be further increased by 31 °C and 14 °C upon thermal cross-linking. The cross-linked polymer thin films exhibit high refractive index (∼1.65, TE mode), high thermo-optic coefficient value (dn/dT) (−1.455 × 10⁻⁴/°C, TE mode), low optical loss (less than 0.24 dB/cm at 1310 nm) and relatively low birefringence (∼0.007).     

Effect of clay modification on the structure and properties of sulfonated poly(ether ether ketone)/clay nanocomposites

Sulfonated poly(ether ether ketone) (SPEEK)/clay hybrid membranes were prepared using three types of commercially available clays, the sodium montmorillonite (IC), hydrophobic organo‐clay with long alkyl chains (OC), and organo‐clay with carboxylic acid end groups (HC). It was found that the SPEEK/HC hybrid membranes achieved the best clay dispersion, with the exfoliation of the clay nano‐platelets when the filler loading was < 10 wt%. The incorporation of the carboxylic acid groups in clay layers also improved the connectivity between the ionic clusters in the membrane, resulting in higher proton conductivity without compromising the dimensional stability of membranes. The selectivity higher than the pristine SPEEK membranes was obtained for the SPEEK/HC hybrid membranes at low filler loading (<10 wt%), with higher proton conductivity and similar methanol permeability. POLYM. COMPOS., 37:2632–2638, 2016. © 2015 Society of Plastics Engineers     

Synthesis and gas transport properties of novel poly(aryl ether ketone)s with branched structure

Poly(aryl ether ketone)s (PAEKs) based on 2‐(3′‐trifluoromethylphenyl) hydroquinone and 4,4′‐difluorobenzophenone were synthesized and characterized in the presence or absence of 2,4′,6‐trifluorobenzophenone (BB′₂ monomer). The influence of the incorporation of a branched structure (BB′₂ monomer) on the gas transport properties of PAEKs was investigated. The results showed that PAEKs with a branched structure possess a higher permeability and selectivity than PAEKs without a branched structure. Moreover, improvements in the permeability and selectivity were enhanced with increasing content of BB′₂ monomer. This synergistic effect on permeability and selectivity was mainly due to the higher fractional free volume and the unique size and distribution of free volume holes arising from the incorporation of the branched structure. © 2013 Society of Chemical Industry     

Branched poly(p‐phenylenevinylene): Synthesis,optical and electrochemical properties

A series of poly(p‐phenylene vinylene) (PPV) derivatives with phenylene vinylene side chains (branched PPVs), PPV0, PPV1, PPV2, and PPV3, were synthesized by the Heck coupling reaction and characterized by TGA, absorption spectra, photoluminescence (PL) spectra, and electrochemical cyclic voltammetry. The branched PPVs showed two absorption peaks in the UV–vis region, corresponding to the conjugated side chains (UV absorption) and the main chains (the visible absorption). Especially the absorption spectrum of PPV3 covers a broad wavelength range from 300 to 500 nm. Introducing the electron‐donating alkoxy substituents on the PPV main chains and increasing the content of the alkoxy groups lead to bathochromic shift of both absorption and PL spectra from PPV1 to PPV2 to PPV3. The onset oxidation potential of the branched PPVs is lower by 0.1–0.2 V than that of PPV, indicating that the electron‐donating ability of the branched PPVs enhanced in comparison with that of PPV. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Stabilization of higher-order structure of poly(phenyleneethynylene)s by metathesis polymerization at the side chains

Novel poly(m-phenyleneethynlene-p-phenyleneethynylene)s bearing polymerizable diene or norbornene groups were synthesized by the Sonogashira–Hagihara coupling polymerization of the corresponding d-hydroxyphenylglycine-derived diiodo monomers with p-diethynylbenzene. These polymers exhibited strong Cotton effects derived from a predominantly one-handed helical conformation in CHCl₃ and tetrahydrofuran, but exhibited weak or no Cotton effects in N,N-dimethylformamide. The metathesis polymerization of the diene and norbornene moieties was performed at the side chains of the polymers under diluted conditions in the presence of a chain-transfer agent, if necessary. The reaction took place intramolecularly, which was confirmed by size exclusion chromatography (SEC) measurements. The polymers exhibited stronger Cotton effects even in polar media after the intramolecular crosslinking, which indicated stabilization of the predominantly one-handed helical structures.     

Synthesis,structural characterization and properties of novel functional poly(ether imide)/titania nanocomposite thin films

In this study, the synthesis, morphology, and thermal properties of new poly(ether imide)/titania nanohybrid films were investigated. The novel diamine containing functional nitrile groups was prepared in two steps by the nucleophilic substitution reaction and it was fully characterized by different techniques. Reaction of this diamine with pyromellitic dianhydride and 4-aminobenzoic acid gave poly(ether imide) with carboxylic acid end groups. This acid functionalized poly(ether imide) was condense with different amount of TiO₂ nanoparticles to provide organic-inorganic bonding, and the flexible films of these hybrid were prepared. The obtained materials were characterized by Fourier transform-infrared spectroscopy, thermogravimetry analysis (TGA), differential scanning calorimetry, X-ray powder diffraction, UV–Vis spectroscopy, field emission-scanning electron microscopy, and transmission electron microscopy (TEM) techniques. TEM of the nanohybrid films with 12% of TiO₂ contents confirms well dispersion of nanoparticles in the polymer matrix. TGA data indicated that the thermal behavior of the hybrid materials was increased with an increasing the content of TiO₂ nanoparticles. The tensile stress–strain of the hybrids was investigated and the resulting nanocomposites showed good mechanical properties. The permeability and selectivity of the PEI/TiO₂ membranes as a function of the titania weight percentage were study and the results indicated that the permeabilities of CO₂ and N₂ increase with increasing the titania content.     

Synthesis, characterizations and properties of new copoly(aryl ether)s with alternate hole- and electron-transporting fluorophores

Three novel copoly(aryl ether)s, consisting of alternate isolated hole-transporting (2,5-dihexyloxy-1,4-distyrylbenzene) and electron-transporting (p-quaterphenyl or aromatic 1,3,4-oxadiazole) segments, were synthesized from corresponding bis(phenol) and bis(fluoride) monomers by nucleophilic displacement reaction. These copolymers are soluble in common organic solvents and exhibit good thermal stability with 5% weight loss temperature above 400 °C in nitrogen atmosphere. The photoluminescent (PL) spectra and quantum yields of these copolymers are dependent on the composition of the isolated fluorophores. The HOMO and LUMO energy levels of these copolymers have been estimated from their cyclic voltammograms. All the observations directly proved that the oxidation in copolymers starts at the hole transporting segments. Moreover, the electron and hole affinities can be enhanced simultaneously by introducing isolated hole-transporting and electron-transporting segments, in which p-quaterphenyl is more electron-affinitive than aromatic 1,3,4-oxadiazole chromophores.