Green synthesis of soluble polyphenol: oxidative polymerization of phenol in water

Abstract

The simple stirring of phenol with an oxidant in water provided a novel green way to synthesize soluble polyphenol. The soluble polyphenol obtained had a high poly(phenylene oxide) unit ratio, poly(phenyleneoxide)/poly(phenylene)=ca. 80/20. Additionally, the insoluble fraction was identified as a poly(phenyleneoxide), which has a crosslinking point for every 5.5×10³ molecular weight. These results suggest that oxidative polymerization in water can be run in a manner to control the coupling selectivity of phenol. Both the soluble polyphenol and the insoluble fraction showed a high thermal stability. Oxidative polymerization in water provides the potential for a formaldehyde-free and regioselected soluble poly(phenyleneoxide) from phenol.     

Development of Poly(Phenylene)-Based Materials for Thin Film Applications: Optical Waveguides and Low Dielectric Materials

Abstract

We have synthesized and evaluated poly(phenylene)-based materials made via spin-coatable polymeric precursors for such thin film applications as optical waveguides and low dielectric materials. Poly(phenylene) precursors were prepared by radical polymerization of cyclohexadiene-1, 2-diol derivatives containing various leaving groups. The precursors were converted into poly(phenylene) either by curing at 300°C or by deep-UV exposure in the presence of a photoacid generator. Poly(phenylene) has a number of desirable properties including good near-IR transmission, low dielectric constant, thermal and environmental stability, low water absorption, and ease of pattern fabrication using microlithographic techniques. Copolymer precursors based on 1,2-diaceto-3,5-cyclohexadiene and styrene derivatives as well as copolymers with Nsubstituted maleimide derivatives were prepared by radical copolymerization. The copolymer precursors were converted into poly(phenylene) copolymers either by annealing at 300°C or by deep-UV exposure in the presence of a photoacid generator. The results of this study indicate that copolymerization allows the incorporation of comonomers that can control dielectric and optical properties as well as glass transition temperature.     

Poly(Azomethine Sulfones). I. Synthesis and Characterization of New Poly(Azomethine Sulfones) Containing Ortho/Para Aromatic Moieties

Abstract

New poly(azomethine sulfones) with linear structures containing methylene bis(2-oxobenzylidene aniline), methylene bis(4-oxobenzylidene aniline), 1,4-bis(4-oxobenzylidene amino)phenylene and 1,4-bis(2-oxobenzylidene amino)phenylene units were prepared in the conventional literature manner by the reaction of azomethine bisphenols (M 1–4) with 4,4′-sulfonyl bischlorobenzene. The resulting polymers were confirmed by IR, ¹H-NMR and elemental analysis, and were characterized by UV measurements, viscosities, solubilities, DSC and thermo-gravimetric analysis (TGA) in air. A difference in the solubility and thermal behavior between the polymers with ortho- and para- chains was observed. The hydrolitic stability of the polymers in 10% wt aqueous sulfuric acid was reasonable     

Characterization of Poly(ethyleneoxyethylene terephthalate‐co‐adipate) using NMR Spectroscopy

Comonomer sequence distribution and ¹H‐NMR chemical shifts were determined for poly(ethyleneoxyethylene terephthalate‐co‐adipate) (PEOETA) copolyester. The sequence distribution of terephthalate (T) and adipate (A) residues was found to be random, which is typical for copolyesters synthesized via bulk polycondensation. The inner methylene protons of EOE residues appeared as a pair of doublets due to chemical shift differences among the EOE‐centered dyad sequences TT, TA, AT, and AA. The four equivalent phenylene protons of T residues appeared as a triplet due to chemical shift differences among the T‐centered triad sequences TTT, TTA (?ATA), and ATA. Higher‐order tetrad and pentad sensitivity were also observed for the inner methylene and phenylene protons, respectively, especially for TT‐ and TTT‐centered sequences. The sequence sensitivity of the phenylene protons was attributed to unique spatial interactions between themselves and protons within adjacent adipate and EOE units. These spatial interactions were confirmed using Nuclear Overhauser Enhancement Spectroscopy (NOESY).     

Polymerization of Bis(Pyridine)bis-(2,4,6-tribromophenoxo)copper(II) Complex (Py2Cu(TBrP)2) by Electrooxidation and Structural Characterization by 1H-NMR, 13C-NMR,and FTIR Spectroscopies

Abstract

Electroinitiated polymerization of bis(2,4,6-tribromophenoxo)- bis(pyridine)copper(II) complex was achieved in dimethylformamide-tetrabutylammonium tetrafluoroborate solvent-electrolyte couple under air or nitrogen at room temperature by constant potential electrolysis. Polymerization conditions were based on the peak potentials measured by cyclic voltammetry. The structural analyses of the polymers were done by ¹H-NMR, ¹³C-NMR, and FTIR spectral analyses along with molecular weight measurements by cryoscopy. The poly(dibromo phenylene oxide)s obtained only at oxidation potentials in either atmosphere were found to be highly linear, indicating mainly 1,4-catenation was taking place.     

Polymeric organosilicon systems. XVII. Synthesis and photochemical and conducting properties of poly[o-and m-(disilanylene)phenylene]s

Poly[o-(tetramethyldisilanylene)phenylene] ( 2a ), poly[o-(1,2-dimethyldiphenyldisilanylene)-phenylene] ( 2b ), poly[m-(tetramethyldisilanylene)phenylene] ( 2c ), and poly[m-(1,2-dimethyldiphenyldisilanylene)phenylene] ( 2d ) were prepared by the sodium condensation reaction of the corresponding 1,2-and 1,3-bis (chlorosilyl)benzenes in toluene. Irradiation of thin films of 2a-2d in air resulted in a rapid decrease of absorption maxima in the ultraviolet region. The photolysis of 2b and 2d in benzene afforded photodegradation products with low molecular weights. When thin films of 2b and 2d were doped with antimony pentafluoride vapor, films which have conductivities of semi-conductor level were obtained. © 1993 John Wiley & Sons, Inc.     

Properties and Structures of Terephthalyl Chloride (TPC) Modified meta‐Aramid Copolymers

The properties and structures of terephthalyl chloride (TPC) modified poly(m‐phenylene isophthalamide) (PMIA) with TPC mole content in acylchloride from 5%–15% were studied in this paper. The composition and structure of the copolymer were determined by ¹H NMR. The content of TPC moiety in the molecular chain was calculated. Thermogravimetric analysis (TGA) and Fourier transform infrared (FTIR) were used to analysis the thermal properties of TPC modified PMIA copolymer. The results show that by introducing TPC units in the PMIA molecular chain, PMIA copolymers with better thermal properties were prepared. With the increase of TPC content, the TPC modified PMIA exhibit increasing thermal stability. The pyrolysis process of the copolymer was detected by FTIR spectra. When the copolymers were pyrolyzed to 500°C, an aryl nitrile band at 2230 cm^?1 appears in the FTIR spectrum. This means that at this temperature breakage of the amide bond occurred.     

A Preliminary Study on Preparation of the Aromatic/Aliphatic Co‐polyurea as Spun Fibers

Aromatic‐aliphatic co‐polyurea has been synthesized from 4,4 prime‐diphenylmethane diisocyanate (MDI), m‐phenylene diamine (m‐PDA), and 1,6‐diaminohexane (HDA) in DMAc by solution polymerization. The chemical structure of the co‐polyurea has been characterized by ¹H‐NMR. The thermal properties of the copolymers were measured by DSC and TGA. The co‐polyurea solutions were spun into fibers by means of wet spinning. The effects of coagulation conditions on the morphologies and mechanical properties of the co‐polyurea as spun fibers are discussed.     

Amperometric Glucose Biosensors Based on Composite Polymeric Structures to Prevent Interferences

ABSTRACT

High sensitive glucose biosensors were realised by oxidative polymerisation of amphiphilic pyrrole monomer-glucose oxidase mixtures, previously adsorbed on platinum electrodes. These sensors, based on H₂O₂ electrooxidation at 0.5V vs SCE, exhibited marked interferences due to electrooxidisable endogenous (ascorbate and urate) and exogenous (paracetamol) compounds. Bilayer structures, combining the preceding polymer film as an outer layer and electrogenerated poly(phenylene diamine), overoxidised polypyrrolic films or Nafion as an inner layer, were fabricated in order to minimise interferences. Finally, the use of Nafion as a semipermeable barrier appeared to be more efficient than the electrogenerated films. The Nafion-based biosensor exhibited glucose sensitivity of 0.4 mA.M^?1; .cm^?2, while interference of ascorbate, urate and paracetamol was negligible.     

Synthesis and characterization of new blue‐light‐emitting polymers based on PPP and PPV having fluorene pendant at vinyl bridge

The new poly(arylene vinylene) derivatives, which are composed of biphenylene vinylene phenylene vinylene, biphenylene vinylene m‐phenylene vinylene, terphenylene vinylene phenylene vinylene, and terphenylene vinylene m‐phenylene vinylene as backbone and bulky fluorene pendants at each vinyl bridge, were designed, synthesized, and characterized. The obtained polymers showed weight‐average molecular weights of 11,100–39,800 with polydispersity indexes ranging from 1.5 to 2.1. The resulting polymers were amorphous with high thermal stability and readily soluble in common organic solvents. The obtained polymers showed blue emission (λ_max = 456–475 nm) in PL spectra, and polymer 4 containing terphenylene vinylene m‐phenylene vinylene showed the most blue shifted blue emission (λ_max = 456 nm). The double layer light‐emitting diode devices fabricated by using obtained polymers as emitter emitted bright blue light. The device showed turn on voltage around 6.5 V and brightness of 70–250 cd/m². © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4923–4931, 2006     

Synthesis of well‐defined rod‐coil block copolymers containing trifluoromethylated poly(phenylene oxide)s by chain‐growth condensation polymerization and atom transfer radical polymerization

Well‐defined trifluoromethylated poly(phenylene oxide)s were synthesized via nucleophilic aromatic substitution (S_NAr) reaction by a chain‐growth polymerization manner. Polymerization of potassium 4‐fluoro‐3‐(trifluoromethyl)phenolate in the presence of an appropriate initiator yielded polymers with molecular weights of ～4000 and polydispersity indices of <1.2, which were characterized by ¹H nuclear magnetic resonance spectroscopy and gel permeation chromatography. Initiating sites for atom transfer radical polymerization (ATRP) were introduced at the either side of chain ends of the poly(phenylene oxide), and used for ATRP of styrene and methyl methacrylate, yielding well‐defined rod‐coil block copolymers. Differential scanning calorimetry study indicated that the well‐defined trifluoromethylated poly(phenylene oxide)s showed high crystallinity and were immiscible with polystyrene. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1049–1057, 2010     

Synthesis and properties of liquid crystalline polyurethanes

1,4-Bis(p-hydroxybenzoate)phenylene was prepared using 1,4-bis(trimethylsiloxy)benzene and p-hydroxybenzoyl chloride as starting materials. A series of novel 1,4-bis(p-hydroxyalkoxybenzoate)phenylene were synthesized by reaction of 1,4-bis(p-hydroxybenzoate) phenylene with 3-brompropanol and 4-bromobutanol, respectively. The liquid crystal polyurethanes were prepared by 1,4-bis(p-hydroxyalkoxybenzoate)phenylene with MDI (p-methylene diphenylenediisocyanate) and 2,4-TDI(2,4-toluenediisocyanate), respectively. The thermotropic properties, the melting point (T _m) and the isotropization temperature (T _i) of the synthesized polyurethanes were characterized by DSC, IR and POM. It showed that all of the polyurethane polymers exhibited thermotropic liquid crystalline properties between 144°C and 260°C. The transition temperature (T _m and T _i) decreased with an increase in the length of the methylene spacer. __________ Translated from Journal of Qingdao University of Science and Technology, 2006, 27(1) (in Chinese)     

Singly and Doubly 1,2‐Phenylene‐Inserted Porphyrin Arch‐Tape Dimers: Synthesis and Highly Contorted Structures

Singly and doubly 1,2‐phenylene‐inserted Ni^II porphyrin arch‐tape dimers 3 and 9 were synthesized from the corresponding β‐to‐β 1,2‐phenylene‐bridged Ni^II porphyrin dimers 5 and 11 via Ni⁰‐mediated reductive cyclization and DDQ/Sc(OTf)₃‐promoted oxidative cyclization as key steps, respectively. Owing to the fused eight‐membered ring(s), 3 showed a more contorted structure than those of previously reported arch‐tape dimers 2 a and 2 b possessing a fused seven‐membered ring. Furthermore, 9 displayed much larger molecular contortion. As the molecular contortion increases, the Q band of the absorption spectrum becomes more red‐shifted and the electrochemcial HOMO–LUMO gap becomes smaller, reaching at 1294 nm and 0.77 eV in 9 , respectively. The effect of molecular contortion on the electronic properties was studied by means of DFT calculations.     

Synthesis and characterization of alt‐bipyridinylene‐phenylene copolymers containing ruthenium(II) complexes

Poly{bis(4,4′‐tert‐butyl‐2,2′‐bipyridine)–(2,2′‐bipyridine‐5,5′‐diyl‐[1,4‐phenylene])–ruthenium(II)bishexafluorophosphate} ( 3a ), poly{bis(4,4′‐tert‐butyl‐2,2′‐bipyridine)–(2,2′‐bipyridine‐4,4′‐diyl‐[1,4‐phenylene])–ruthenium(II)bishexafluorophosphate} ( 3b ), and poly{bis(2,2′‐bipyridine)–(2,2′‐bipyridine‐5,5′‐diyl‐[1,4‐phenylene])–ruthenium(II)bishexafluorophosphate} ( 3c ) were synthesized by the Suzuki coupling reaction. The alternating structure of the copolymers was confirmed by ¹H and ¹³C NMR and elemental analysis. The polymers showed, by ultraviolet–visible, the π–π* absorption of the polymer backbone (320–380 nm) and at a lower energy attributed to the d–π* metal‐to‐ligand charge‐transfer absorption (450 nm for linear 3a and 480 nm for angular 3b ). The polymers were characterized by a monomodal molecular weight distribution. The degree of polymerization was approximately 8 for polymer 3b and 28 for polymer 3d . © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2911–2919, 2004     

Effect of lateral substitution on supramolecular liquid crystal associates induced by hydrogen-bonding interactions between 4-(4′-pyridylazo-3-methylphenyl)-4′′-alkoxy benzoates and 4-substituted benzoic acids

Five laterally methyl-substituted pyridine-based derivatives of the title compounds (I 8–I 16), with molecular formula 4-C_nH_2n+1O-C₆H₄COOC₆H₃(3-CH₃)-N=N-C₅H₄N were prepared and their molecular formulae elucidated via elemental analyses, infrared, nuclear magnetic resonance and mass spectra. The number of carbon atoms in the alkoxy chain (n) varies between 8, 10, 12, 14, and 16 carbons. The newly prepared pyridine-based derivatives were investigated for their mesophase behaviour by differential scanning calorimetry and polarised optical microscopy; most of them were found to possess monotropic smectic C (SmC) mesophase. Two groups (A and B) of the 1:1 hydrogen-bonded associates, formed between each of the derivatives I 8– I 16 and two types of 4-substituted benzoic acids (II), were prepared and similarly characterised to investigate the effect of lateral methyl substitution on the central phenylene ring, as well as terminal polar substituents and alkoxy-chain length on the stability of the mesophases induced by intermolecular hydrogen bonding. In Group A complexes, mesomorphic 4-alkoxy benzoic acids, that carry the terminal n-alkoxy group of varying chain length, were used. The other series of complexes (Group B) is composed from the same pyridine-based derivatives and each of the non-mesomorphic 4-substituted benzoic acids that carries small compact polar groups, varying between CH₃O, CH₃, H, Cl, Br, and CN. All complexes prepared were investigated for their mesophase behaviour by differential scanning calorimetry and polarised optical microscopy and found to be purely smectogenic, possessing SmC as the only mesophase observed. The formation of the hydrogen-bonded complexes was confirmed by constructing their binary phase diagrams, which cover the whole range of concentration of the two complements.     

STUDIES ON PHASE SEPARATION OF POLYESTERIMIDE-MODIFIED EPOXY RESINS. I. SYNTHESES AND PROPERTIES OF ORGANO-SOLUBLE POLYESTERIMIDES

ABSTRACT

A series of polyesterimides based on aromatic bis(trimellitate) dian-hydride in main chain were prepared by polycondensation of t-butyl-p-phenylenebis(trimellitate) dianhydride (BPBDA) and phenylene bis(trimellitate) dianhydride (PBDA) with benzidine and its derivates. The results show that the incorporation of noncoplanar structure led by introducing alkyl substituents on dianhydride and benzidine can improve the solubility of polyesterimides in organic solvents. It also displays that the introducing substituents lead to a decrease in glass transition temperature and influence the β relaxation of PEsI. By comparing the chemical structure and the dynamical mechanic date, we suggest that the β relaxation correspond to the motion involving the imide ring and phenylene groups of the diamine.     

Gas permeability of cardo-poly(ether-ether-ketone) and poly(phenylene sulfide)

The gas permeability and sorption of CO₂ and N₂O was measured on cardo-poly(ether-ether-ketone) (C-PEEK) and poly(phenylene sulfide) (PPS) at 298 K. The results are discussed on the basis of the dual-mode model. Results obtained from measurements at 308 K are compared with literature data of poly(phenylene oxide) (PPO), poly(sulfone) (PSU) and poly(carbonate) (PC). While C-PEEK shows similar transport properties as PC and PSU, the values of PPS are distinctly lower. The solubility of CO₂ in the various polymers as well as the correlation of the permeability coefficients of the same polymers for He, Ar, CO₂, N₂, and CH₄ with the kinetic molecular diameter of the gases indicate a simple relation of the transport properties with the polymer density.     

Acyclic diene metathesis polymerization of 2,5‐dialkyl‐1,4‐divinylbenzene with molybdenum or ruthenium catalysts: Factors affecting the precise synthesis of defect‐free,high‐molecular‐weight trans‐poly(p‐phenylene vinylene)s

Factors affecting the syntheses of high‐molecular‐weight poly(2,5‐dialkyl‐1,4‐phenylene vinylene) by the acyclic diene metathesis polymerization of 2,5‐dialkyl‐1,4‐divinylbenzenes [alkyl = n‐octyl ( 2 ) and 2‐ethylhexyl ( 3 )] with a molybdenum or ruthenium catalyst were explored. The polymerizations of 2 by Mo(N‐2,6‐Me₂C₆H₃) (CHMe₂ Ph)[OCMe(CF₃)₂]₂ at 25 °C was completed with both a high initial monomer concentration and reduced pressure, affording poly(p‐phenylene vinylene)s with low polydispersity index values (number‐average molecular weight = 3.3–3.65 × 10³ by gel permeation chromatography vs polystyrene standards, weight‐average molecular weight/number‐average molecular weight = 1.1–1.2), but the polymerization of 3 was not completed under the same conditions. The synthesis of structurally regular (all‐trans), defect‐free, high‐molecular‐weight 2‐ethylhexyl substituted poly(p‐phenylene vinylene)s [poly 3 ; degree of monomer repeating unit (DP_n) = ca. 16–70 by ¹H NMR] with unimodal molecular weight distributions (number‐average molecular weight = 8.30–36.3 × 10³ by gel permeation chromatography, weight‐average molecular weight/number‐average molecular weight = 1.6–2.1) and with defined polymer chain ends (as a vinyl group, ? CH?CH₂) was achieved when Ru(CHPh)(Cl)₂(IMesH₂)(PCy₃) or Ru(CH‐2‐OⁱPr‐C₆H₄)(Cl)₂(IMesH₂) [IMesH₂ = 1,3‐bis(2,4,6‐trimethylphenyl)‐2‐imidazolidinylidene] was employed as a catalyst at 50 °C. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6166–6177, 2005     

Thermal stability and degradation behavior of novel wholly aromatic azopolyamide-hydrazides

Thermal stability and degradation behavior of a series of novel wholly aromatic polyamide-hydrazides containing azo groups in their main chains have been investigated in nitrogen and in air atmospheres using differential scanning calorimetry (DSC), thermogravimetry (TG), infrared spectroscopy (IR) and elemental analysis. The influences of controlled structural variations and molecular weight on the thermal stability and degradation behavior of this series of polymers have also been studied. The structural differences were achieved by varying the content of para- and meta-substituted phenylene rings incorporated within this series. Azopolyamide-hydrazides having different molecular weights of all para-substituted phenylene type units were also examined. The polymers were prepared by a low temperature solution polycondensation reaction of p-aminosalicylic acid hydrazide [PASH] and an equimolar amount of 4,4′-azodibenzoyl chloride [4,4′ADBC] or 3,3′-azodibenzoyl chloride [3,3′ADBC] or mixtures of various molar ratios of 4,4′ADBC and 3,3′ADBC in anhydrous N,N-dimethyl acetamide [DMAc] containing lithium chloride as a solvent at −10 °C. All the polymers have the same structural formula except the mode of linking phenylene units in the polymer chain. The results clearly reveal that these polymers are characterized by high thermal stability. Their weight loss occurred in three distinctive steps. The first was small and assigned to the evaporation of absorbed moisture. The second was appreciable and was attributed to the cyclodehydration reaction of the hydrazide groups into 1,3,4-oxadiazole rings by losing water, combined with elimination of azo groups by losing molecular nitrogen. This is not a true degradation but rather a thermo-chemical transformation reaction of the azopolyamide-hydrazides into the corresponding polyamide-1,3,4-oxadiazoles. The third was relatively severe and sharp, particularly in air, and corresponded to the decomposition of the resulting polyamide-1,3,4-oxadizoles. In both degradation atmospheres, the improved resistance to high temperatures was always associated with increased content of para-phenylene moieties of the investigated polymer. The better thermal stability of the wholly para-oriented type of polymer relative to the other polymers is attributed to its greater chain symmetry which is responsible for its greater close packing, rod-like structure and consequently stronger intermolecular bonds which would be more difficult to break and therefore more resistance to high temperatures. Further, with exception of 160-200 °C temperature range, where the lower molecular weight samples showed considerable weight losses which were most probably due to hydrogen bonded DMAc, all the wholly para-oriented phenylene type of polymer samples behaved similarly regardless of their respective molecular weight. This seems to indicate that the structural building units responsible for high thermal stability of the polymers are their characteristic groups, such as aromatic moieties, amide and hydrazide linkages in case of azopolyamide-hydrazides, and 1,3,4-oxadiazole rings, aromatic nuclei and amide linking bonds in case of polyamide-1,3,4-oxadiazoles, rather than the longer chain segments.     

Synthesis of terphenyl oligomers as molecular electronic device candidates

Six functionalized bis(phenylene ethynylene)-p,p-terphenyls (BPETs) have been synthesized as potential molecular electronic devices. The molecules containing mono- and dinitro terphenyl cores, were rationally designed based on the electronic properties recently found in oligo(phenylene ethynylene)s (OPEs). From our understanding of the conductance properties in OPEs, improvement of electronic properties may be possible by using BPETs due to a higher rotational barrier between the central aromatic rings of the compounds prepared here. BPETs cores were functionalized with nitro groups and with different metallic adhesion moieties (alligator clips) to provide new compounds for testing in the nanopore and planar testbed structures.