Preparation and chelating properties of polychalcones derived from 8-hydroxyquinoline-5-aldehyde

The polychalcones designated as poly(7-acetyl-8-hydroxyquinoline-5-aldehyde) (PAHQ) were prepared by Friedel-Crafts (F.C.) acetylation of 8-hydroxyquinoline-5-aldehyde (HQA) in nitrobenzene using AlCl₃ as F.C. catalyst. The polycondensation was carried out in a single step and under different experimental conditions. It was shown that the most likely mechanism of the reaction is F. C. acetylation of HQA followed by condensation of the acetyl and aldehyde groups leading to polychalcones. The polychalcone samples, designated as PAHQ, were characterized by determining nitrogen and hydroxy content, by IR spectroscopy, by bromination reactions, by number average molecular weights, by viscometric study, and by thermogravimetry. Polymeric chelates of selected PAHQ polychalcone samples with various metal ions have been prepared and characterized. Ion exchanging properties of PAHQ polychalcones were also studied by employing the batch equilibration method.     

Synthesis,characterization, and optoelectronic properties of two new polyfluorenes/poly(p‐phenylenevinylene)s copolymers

Two novel copolymers of polyfluorenes/poly(p‐phenylenevinylene)s copolymers with p‐tert‐butyl‐phenylenemethylene groups in the C‐9 position of alternating fluorene unit, poly[1,4‐(2,5‐dibutyloxyl)‐phenyleneviny lene‐alt‐9‐(p‐tert‐butyl‐phenylenemethylene)fluorene] and poly[1,4‐(2,5‐dioctyloxyl)‐phenylenevinylene‐alt‐9‐(p‐tert‐butyl‐phenylenemethylene)fluorine], have been synthesized via the Heck polycondensation reaction. The synthesized polymers were characterized by FTIR, NMR, DSC, TGA, UV–vis, and PL spectra. The polymers showed high glass transition temperatures and good thermal stability. A polymer light‐emitting diode with the configuration ITO/PEDOT:PSS/P2/Ca/Al has been fabricated. The device emitted a yellow light with a peak wavelength of 578 nm similar to the PL spectra of the copolymer film. A maximal luminance of 534 cd/m² was obtained at a driving voltage of 24.5 V. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3955–3962, 2006     

Synthesis and characterization of new flame‐retardant poly(amide‐imide)s containing phosphine oxide and hydantoin moieties in the main chain

Six new flame‐retardant poly(amide‐imide)s (PAIs) 9a–f with high inherent viscosities containing phosphine oxide and hydantoin moieties in main chain were synthesized from the polycondensation reaction of N,N′‐(3,3′‐diphenylphenylphosphine oxide) bistrimellitimide diacid chloride 7 with six hydantoin derivatives 8a–f by two different methods such as solution and microwave assisted polycondensation. Results showed that the microwave assisted polycondensation, by using a domestic microwave oven, proceeded rapidly, compared with solution polycondensation, and was completed in about 7–9 min. All of the obtained polymers were fully characterized by means of elemental analysis, viscosity measurements, solubility test, and FTIR spectroscopy. Thermal properties and flame retardant behavior of the PAIs 9a–f were investigated using thermal gravimetric analysis (TGA and DTG) and limited Oxygen index (LOI). Data obtained by thermal analysis (TGA and DTG) revealed that these polymers showed good thermal stability. Furthermore, high char yields in TGA and good LOI values indicated that these polymers are capable of exhibiting good flame retardant properties. These polymers can be potentially utilized in flame retardant thermoplastic materials. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5062–5071, 2006     

Studies on the semirigid chain polyamide—poly(1,4-phenyleneterephthalamide)

In this article, the polycondensation of terephthaloyl chloride and p-phenylenediamine was systematically studied, including the liquid–crystalline state of the solution and the spinning of poly(1,4-phenyleneterephthalamide) (PPTA). High-molecular-weight PPTA with ε_inh = 5–7 was prepared and the main factors influencing the solution polycondensation of 1,4-phenylenediamine with terephthaloyl chloride were studied in detail. Experimental results showed that the water content of the reaction system, reactant concentration, and volume ratio of mix solvents have a great influence on the inherent viscosity of the poly(1,4-phenyleneterephthalamide) obtained. The highest ε_inh was obtained at 0.3M/liter reactant concentration in a mixed solvent ratio HMPA/DMAC of 4/1 (by volume), at 0.35M/liter reactant concentration in a mixed solvent of HMPA/NMP = 7/3, and at 0.5M/liter of reactant concentration in a mixed solvent of HMPA/THF = 9/1. The water content must be controlled to less than 100 ppm in the polymerization system. In the early stage of the polycondensation process, the ε_inh of the polymer obtained increased rapidly with time. The system gelled within 2 or 3 min, while the monomer conversion reached about 100%. However, the reaction of polycondensation continued after gelation and the ε_inh of the polymer increased appreciably. We have studied the viscosity behavior at 20–155°C for the anisotropic solution of PPTA in 100% sulfuric acid (ε_inh of PPTA 2.5–4.9). Experimental results showed that, at low concentrations the viscosity of isotropic solution increases with the increase of polymer concentration to reach a maxium near the critical polymer concentration, beyond which the solution changes to an anisotropic liquid–crystalline solution. The appropriate spinning region was obtained as shown in the phase diagram determined by viscosity, degree of depolarization anisotropy, and region of thermal depolymerization. Fibers of PPTA with high modulus and high tenacity were obtained by dry-jet wet spinning. The fibers obtained have a tenacity of ～22 g/denier, a modulus of ～600 g/denier, and elongation at break ～3.5%.     

Poly(phenylene sulfide): Polymerization kinetics and characterization

The polycondensation kinetics of aromatic nucleophilic substitution on 1,4-dichlorobenzene by sodium sulfide has been investigated at 195°C in N-methyl pyrrolidone. The reaction follows second-order kinetics. The rate is bimodal with an initial slow rate till 50% conversion followed by a faster rate between 50 and 97% conversion. The specific reaction rates have been evaluated as 3.97 × 10^?3 L m^?1 s^?1 and 1.02 × 10^?2 L m^?1 s^?1 for the initial and later part (50–97%) of the reaction. The development of the degree of polymerization with reaction time was followed by end-group analysis and intrinsic viscosity measurements of polymer samples collected at different conversions. The reaction differs from conventional polycondensation reactions in two aspects. Polymer formation occurs at low conversions, and a significant amount of uncreacted monomer is present even at very high conversions. Unlike other precipitation polymerization reactions, the polymer chain continues to grow even after precipitation.     

Synthesis and properties of novel flame‐retardant poly(amide‐imide)s containing phosphine oxide moieties in main chain by microwave irradiation

Eight new flame‐retardant poly(amide‐imide)s with high inherent viscosities containing phosphine oxide moieties in main chain were synthesized from the polycondensation reaction of N,N′‐(3,3′‐diphenylphenylphosphine oxide) bistrimellitimide diacid chloride 7, with eight ;aromatic diamine 8a–h by two different methods such as solution and microwave‐assisted polycondensation. Results showed that the microwave‐assisted polycondensation by using a domestic microwave oven proceeded rapidly, compared with solution polycondensation and were completed within about 10–12 min. The resulting poly(amide‐imide)s 9a–h showed high thermal stability and flame‐retardant properties. All of the obtained polymers were fully characterized by means of elemental analysis, viscosity measurements, solubility test, and FTIR spectroscopy. Thermal properties of the PAIs 9a–h were investigated by using thermal gravimetric analysis (TGA), derivative thermogravimetric analysis (DTG), and differential scanning calorimetry (DSC). Char yield measurements at 600°C demonstrated that incorporating phosphine oxide moieties in polymer backbone markedly improves their flame retardancy. All of the earlier polymers were soluble at room temperature in various organic solvents such as NMP, DMF, DMSO, DMAc, and concentrated sulfuric acid. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4263–4269, 2006     

Synthesis and Optical Properties of Nonlinear Optical Polyarylates

Several polyarylates based on bisbenzylidenoketones have been synthesized by interfacial polycondensation. Two distinct types of polymers have been obtained: guest-host systems and polyarylates with NLO (nonlinear optical) side chains. The dispersion of the linear refractive index (n ₀) is measured over the wavelength range from 800 to 2000 nm. The Holing formula, based on a semiclassical model of a simple harmonic oscillator, is used to calculate the NLO susceptibility X⁽³⁾.     

Synthesis and characterization of novel optically active poly(amide–imide)s containing N,N′‐(pyromellitoyl)‐bis‐L‐valine diacid chloride and 5,5‐disubstituted hydantoin derivatives under microwave irradiation

Pyromellitic dianhydride (1,2,4,5‐benzenetetracarboxylic acid 1,2,4,5‐dianhydide) was reacted with L ‐valine in a mixture of acetic acid and pyridine (3:2) at room temperature, and then was refluxed at 90–100 °C, N,N′‐(pyromellitoyl)‐bis‐L ‐valine diacid was obtained in quantitative yield. The imide–acid was converted to N,N′‐(pyromellitoyl)‐bis‐L ‐valine diacid chloride by reaction with thionyl chloride. Rapid and highly efficient synthesis of a number of poly(amide–imide)s was achieved under microwave irradiation using a domestic microwave oven by polycondensation of N,N′‐(pyromellitoyl)‐bis‐L ‐valine diacid chloride with six different derivatives of 5,5‐disubstituted hydantoin compounds in the presence of a small amount of a polar organic medium that acts as a primary microwave absorber. A suitable organic medium was o‐cresol. The polycondensation proceeded rapidly, compared with conventional melt polycondensation and solution polycondensation and was almost completed within 8 min, giving a series of poly(amide–imide)s with inherent viscosities in the range 0.15–0.36 dl g^?1. The resulting poly(amide–imide)s were obtained in high yield and are optically active and thermally stable. All of the above compounds were fully characterized by Fourier‐transform infrared (FT‐IR) spectroscopy, elemental analysis, inherent viscosity (η_inh) measurements, solubility testing and specific rotation measurements. The thermal properties of the poly(amide–imide)s were investigated by using thermogravimetric analysis. Copyright © 2004 Society of Chemical Industry     

Synthesis,extraction, and adsorption properties of calix[4]arene‐poly(ethylene‐glycol) crosslinked polymer

Novel calix[4]arene‐poly(ethylene glycol) crosslinked polymer (CCP) has been synthesized by the polycondensation reaction between a p‐tert‐butylcalix[4]arene derivative and dihydroxyl capped poly(ethylene glycol) (DHPEG, M_n = 1000) catalyzed by neodymium tosylate. The hydrogel, consisted of 66.9% water and 33.1% CCP, can selectively extract aromatic organic molecules from aqueous solution according to the diameter of the guest molecules, which infers that the diameter of the calix[4]arene cavity is about 5.4 Å and the conformation of calix[4]arene units altered from cone conformation to 1,3‐alternate conformation during the polycondensation reaction. Furthermore, CCP can also adsorb naphthalene from gas phase, showing much higher capacity than active carbon does, which may have some potential applications in the field of separation and environment protection. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis of new polyesters with chelating subunits by solution and interfacial polycondensation

New polyesters have been prepared by solution and interfacial polycondensation of acid chlorides obtained from bis‐α,ω‐polymethylene‐[(2‐methoxy)phenoxy]acetic acids, acid‐ether siderophores AE _n (n being the number of methylene units), and diols including bisphenol A, ethylene glycol and propanediol. For interfacial polycondensation, average molecular weights range from 1000 to 4500 g mol^?1; at higher temperature the molecular weights increase but the yield is smaller. Differential scanning calorimetry shows T_g ranging from ?5 to + 110 °C. Polyesters are crystalline with n = 6 and amorphous with n = 2 and 4; in addition, increasing n in AE _n increases molecular weights and T_g values. In solution polycondensation, the average molecular weights are around 3000 g mol^?1 and T_g is low. © 2001 Society of Chemical Industry     

New Efficient Dielectric and Antistatic Materials Based on Oligoaminophenols

New polyconjugated oligomers—oligoaminophenols—have been prepared by the oxidative polycondensation reaction of aminophenols (APs) in the presence of oxidants (H₂O₂, NaOCl, KOH plus O₂). It has been established that the reactivity of AP increases with the series of m- < o- < p-isomers in this reaction. The oligoaminophenols synthesized show a high reactivity in electron-exchange processes and in reactions with the oxirane ring of epichlorohydrin and epoxy resins. They are highly efficient antioxidants and antistatic agents. © 1997 SCI     

Property Modulation of Poly(trimethylene terephthalate) by Incorporation of Nonlinear Isophthalate Units

Summary: P(TT‐co‐TI)s with up to 20 mol‐% of TI units were synthesized in order to modulate the thermal and mechanical properties of PTT and were characterized by FT‐IR, ¹H NMR, DSC, and DMA analysis. PTI and PTT were also synthesized for the purpose of comparison. The polymerizations proceeded via two steps, i.e., transesterification and polycondensation. Manganese acetate and titanium butoxide were used as catalysts for the transesterification and polycondensation steps, respectively. During the polymerization, the P(TT‐co‐TI) copolymers and PTI exhibited similar transesterification rates, whereas PTI showed a slower rate. The polycondensation rate decreased with increasing TI content in P(TT‐co‐TI). The synthesis of the polymers was confirmed by FT‐IR and ¹H NMR analysis. DSC and DMA analysis indicated that the P(TT‐co‐TI)s are random copolymers, and that their T_cc increased and T_m decreased as the TI content in the P(TT‐co‐TI) increased. The peel strength between the P(TT‐co‐TI) films and an aluminum sheet increased as the TI content in the copolymer increased. The melt‐quenched films of the PTT and P(TT‐co‐TI) copolymers had similar tensile strengths and initial moduli. The dyeing property of the P(TT‐co‐TI) films was enhanced by increasing the TI content.

DSC heating thermograms of the melt‐quenched PTT, PTI, and P(TT‐co‐TI)s.     

Thermotropic mesomorphic polyesters. I. Copolyesters of terephthalic acid,hydroquinone, and flexible diols

A new series of copolyesters has been synthesized by low-temperature solution polycondensation of terephthaloyl dichloride hydroquinone and flexible diols such as 1,2-propane diol, 1,4-butanediol, diethylene glycol, (cis) 1,4-cyclohexanediol and (cis + trans) 1,4-bis(hydroxymethyl) cyclohexane. The copolyesters are all insoluble and display thermotropic mesophases at relatively lower transitions than other commercially important systems. The transition temperatures, the crystallinity, and thermal characterization are reported.     

Preparation and characterization of new optically active poly(amide‐imide)s derived from N,N‐(4,4′‐Oxydiphthaloyl)‐bis‐(s)‐(+)‐valine diacid chloride and aromatic diamines

4,4′‐Oxydiphthalic anhydride (1) was reacted with (s)‐(+)‐valine (2) in acetic acid and the resulting imide‐acid 3 was obtained in high yield. This compound 3 was converted to diacid chloride 4 by reaction with excess amount of thionyl chloride. The polycondensation reaction of diacid chloride 4 with several aromatic diamines such as 4,4′‐sulfonyldianiline (5a), 4,4′‐diaminodiphenyl methane (5b), 4,4′‐diaminodiphenylether (5c), p‐phenylenediamine (5d), m‐phenylenediamine (5e), and 4,4′‐diaminobiphenyl (5f) was performed by two conventional methods: low temperature solution polycondensation and a short period reflux conditions. To compare conventional solution polycondensation reaction methods with microwave‐assisted polycondensation, the reactions were also carried out under microwave conditions in the presence of small amount of o‐cresol that acts as a primary microwave absorber. The reaction mixture was irradiated for 4 min with 100% of radiation power. Several new optically active poly(amide‐imide)s with inherent viscosity ranging from 0.26–0.44 dL/g were obtained with high yield. All of the above polymers were fully characterized by ¹H‐NMR, FTIR, elemental analyses, and specific rotation techniques. Some structural characterizations and physical properties of these new optically active poly (amide‐imide)s are reported. POLYM. ENG. SCI. 46:558–565, 2006. © 2006 Society of Plastics Engineers     

Sono-assisted Synthesis of MgAl-layered Double Hydroxide Nanosheet/multiwalled Carbon Nanotube Filler for the Fabricating of L-isoleucine Amino Acid Based Polymer Nanocomposites

Hybrid of acid functionalized multiwalled carbon nanotubes and layered double hydroxides were prepared by coprecipitation reaction of the Al(NO₃)_3·9H₂O, Mg(NO₃)_2·6H₂O, and acid functionalized multiwalled carbon nanotubes under ultrasonic irradiation. An optically active amino acid containing poly(amide-imide) was synthesized by the direct polycondensation reaction of the N,N′-(pyromellitoyl)-bis-L-isoleucine diacid and diamine using molten tetra-n-butylammonium bromide. These three-dimensional nanofillers were used as reinforcing agent to enhance the performance of chiral poly(amide-imide). The structure and morphology of the hybrid materials were confirmed by Fourier transformed infrared spectroscopy, X-ray diffraction, field emission and transmission electron microscopy, and thermogravimetry analysis techniques.     

Electrospun Silica—Polybenzimidazole Nanocomposite Fibers

A new route for the manufacturing of silica/poly(benzimidazole) (PBI) nanocomposites fibers is described. PBI was synthesized via melt polycondensation and polycondensation in poly(phosphoric acid). Solutions of PBI and silica nanoparticles in N,N‐dimethylacetamide (DMAc) were electrospun to fibers and non‐wovens. The resulting materials were analyzed by ATR‐IR spectroscopy, small‐angle X‐ray scattering (SAXS) and nitrogen sorption measurements. The non‐wovens could be processed towards dense, cross‐linked membranes by hot pressing and treatment with p‐xylylene dichloride.

     

Synthesis,characterization of phosphine oxide-containing polyimides and their use as selective membrane for dopamine

Tris-(p-aminophenoxy)phosphineoxide, t-APPO, was prepared from 4-nitrophenol and POCl₃, followed by hydrogenation. A series of polyimides prepared from t-APPO and the corresponding dianhydrides by two-stage polycondensation method was characterized by Fourier Transform Infrared Spectrometer (FTIR), GPC, thermal analysis and physical methods. Moreover, in order to check the permeation properties of the resulting polyimide film, the selectivity of the polyimide-coated electrode toward electroactive species (ascorbic acid and dopamine) was examined by means of cyclic voltammetry (CV), differential pulse voltammetry (DPV) and time-base amperometric measurement (TB) techniques. As a result, it has been found that polyimide electrode showed selective permeation for dopamine while blocking the permeation of ascorbic acid through film. Therefore, it has been claimed that phosphine oxide-containing polyimide electrode can be used as a dopamine-selective membrane in the presence of ascorbic acid.     

Properties of a branched polyester ether as a function of the preparation method

Properties of a branched polyester ether elastomer have been examined by using two widely differing preparation methods: (1) prepared to final molecular weight by using melt polycondensation (MP) and (2) prepared to an intermediate molecular weight by using melt polycondensation followed by solid phase polycondensation to the final molecular weight (SP). Differences in T_m were attributed to annealing during the SP process and also to apparent changes in monomer sequence distribution in the polymer chains. Crystallization during cooling (DSC) and melt viscosity appeared to be solely a function of molecular weight rather than of preparation history. Molecular weight distribution was exponentially dependent on viscosity average molecular weight for the MP samples, but the distribution was linearly dependent for the SP case which more nearly represents equilibrium conditions. Polymer mechanical properties did not vary much in spite of the pronounced differences observed.     

Facile synthesis of novel optically active poly(amide‐imide)s containing N,N′‐(pyromellitoyl)‐bis‐l‐phenylalanine diacid chloride and 5,5‐disubstituted hydantoin derivatives under microwave irradiation

Pyromellitic dianhydride (1,2,4,5‐benzenetetracarboxylic acid 1,2,4,5‐dianhydide) (1) was reacted with L‐phenylalanine (2) in a mixture of acetic acid and pyridine (3 : 2) at room temperature, then was refluxed at 90–100°C and N,N′‐(Pyromellitoyl)‐bis‐L ‐phenylalanine diacid (3) was obtained in quantitative yield. The imide‐acid (3) was converted to N,N′‐(Pyromellitoyl)‐bis‐L ‐phenylalanine diacid chloride (4) by reaction with thionyl chloride. Rapid and highly efficient synthesis of poly(amide‐imide)s (6a–f) was achieved under microwave irradiation by using a domestic microwave oven from the polycondensation reactions of N,N′‐(Pyromellitoyl)‐bis‐L ‐phenylalanine diacid chloride (4) with six different derivatives of 5,5‐disubstituted hydantoin compounds (5a–f) in the presence of a small amount of a polar organic medium that acts as a primary microwave absorber. Suitable organic media was o‐cresol. The polycondensation proceeded rapidly, compared with the conventional melt polycondensation and solution polycondensation, and was almost completed within 10 min, giving a series of poly(amide‐imide)s with inherent viscosities about 0.28–0.44 dL/g. The resulting poly(amide‐imide)s were obtained in high yield and are optically active and thermally stable. All of the above compounds were fully characterized by means of FTIR spectroscopy, elemental analyses, inherent viscosity (η_inh), solubility test and specific rotation. Thermal properties of the poly(amide‐imide)s were investigated using thermal gravimetric analysis (TGA). © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 516–524, 2004     

Thermal behavior of aryl-aliphatic polyamides

Low molecular weight poly(p-phenylene sebacamides) and (m-phenylene sebacamides) were prepared by interfacial polycondensation by varying the concentration of p-and m-phenylenediamine in the initial feed. The polymers were characterized by intrinsic viscosity measurement and IR spectra. The relative thermal stability was evaluated by differential thermal analysis and dynamic thermogravimetry in air and nitrogen atmospheres. A systematic dependence of stability on intrinsic viscosity of poly(m-phenylene sebacamide) was observed indicating an endgroup initiation of degradation. No such dependence was observed in poly(p-phenylene sebacamide). A probable mechanism for the thermal degradation has been proposed.