Amine–quinone polyimides

Two dianiline monomers were prepared by the reaction of either 4,4′‐methylenedianiline or 4,4′‐oxydianiline with 1,4‐benzoquinone. These monomers were used to synthesize a series of amine–quinone polyimides by condensation with either 3,3′,4,4′‐benzophenonetetracarboxylic dianhydride or 4,4′‐(hexafluoroisopropylidene) diphthalic anhydride to make the corresponding polyamic acid. The polyamic acids were converted to the polyimides by thermal imidization at 290 °C. The amine–quinone polyimides gave freestanding films with tensile strengths in the range of 90 to 150 MPa and Young's moduli of 0.9 to 1.5 GPa. The thermal decomposition temperature under nitrogen was 440 to 480 °C and the glass‐transition temperature was in the range of 280 to 310 °C. The amine–quinone polyimides had the excellent thermal and mechanical properties that one expects for polyimides. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 4044–4049, 2001     

Amine–quinone polyurethanes containing N‐alkylated amine–quinone monomers

A series of amine–quinone diol monomers, containing the 2,5‐diamino‐1,4‐benzoquinone group, were synthesized where the alkyl group on the amine was varied from methyl to ethyl to n‐propyl. Polyurethanes were prepared from these monomers by condensation polymerization in N,N‐dimethylformamide solution with toluene diiscyanate and poly(tetrahydrofuran) diol (M_n = 650). These amine–quinone polyurethanes were used as binders in metal particle tape. Samples were exposed to pH 2.0 aqueous buffer and the all amine–quinone polymers were shown to be superior in their ability to protect the iron particle against corrosion, relative to the commercial binders. There was no significant difference in the ability of the three amine–quinone polymers to inhibit corrosion. Clearly the increasing the steric bulk at the nitrogen did not affect their ability to inihibit corrosion. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 3284–3292, 2000     

Preparation of sulfur‐quinone polyurethanes and their use to inhibit the corrosion of iron particles

A sulfur‐quinone diol monomer, 2,5‐bis‐(2‐hydroxyethylthio)‐1,4‐benzoquinone (SQM‐2), was prepared by the reaction of 2‐mercaptoethanol with benzoquinone. SQM‐2 and polycaprolactone diol (number‐average molecular weight = 1250) were condensed with toluene diisocyanate to give sulfur‐quinone polyurethanes. Two compositions were prepared, SQPU‐1 containing 7 mol % SQM‐2 and SQPU‐2 containing 35 mol % SQM‐2. These thermoplastic polyurethanes were soluble in solvents used in magnetic tape coating processes. The polymers were used to prepare magnetic coatings containing state‐of‐the‐art commercial iron particles. The sulfur‐quinone polyurethanes protected the iron particles against corrosion from a pH 2.0 aqueous buffer. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 3278–3283, 2000     

Amine–Boranes: Green Hypergolic Fuels with Consistently Low Ignition Delays

Complexation of amines with borane converts them to hypergols or decreases their ignition delays (IDs) multifold (with white fuming nitric acid as the oxidant). With consistently low IDs, amine–boranes represent a class of compounds that can be promising alternatives to toxic hydrazine and its derivatives as propellants. A structure–hypergolicity relationship study reveals the necessary features for the low ID.     

Diels–Alder reaction with anthracene and quinone derivatives on the dendritic periphery

Diels–Alder (DA) adducts including 24, 48, and 96 bicyclo end groups on the dendritic periphery were prepared by the reaction of anthracene on the dendrimers (first to fourth generation) and 1,4‐benzoquinone as well as 1,4‐naphtoquinone in boiled toluene. The structural information of DA adducts on the dendritic periphery was received from the hyperfine structural analysis by ¹H NMR spectroscopy. The gel permeation chromatography of DA products revealed very low polydispersity values and decreased regular retention time according to increasing generation. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2155–2161, 2004     

PC‐Activated Bimetallic Rhodium Xantphos Complexes: Formation and Catalytic Dehydrocoupling of Amine–Boranes

{Rh(xantphos)}‐based phosphido dimers form by P? C activation of xantphos (4,5‐bis(diphenylphosphino)‐9,9‐dimethylxanthene) in the presence of amine–boranes. These dimers are active dehydrocoupling catalysts, forming polymeric [H₂BNMeH]_n from H₃B?NMeH₂ and dimeric [H₂BNMe₂]₂ from H₃B?NMe₂H at low catalyst loadings (0.1 mol %). Mechanistic investigations support a dimeric active species, suggesting that bimetallic catalysis may be possible in amine–borane dehydropolymerization.     

Synthesis of Well‐Defined Amphiphilic Core–Shell Particles Containing Amine‐Rich Shells

A new route to synthesize amphiphilic core–shell particles that consist of well‐defined hydrophobic polymer cores and poly(vinylamine) (PVAm) shells has been developed. The PVAm was treated with a small amount of tert‐butyl hydroperoxide to generate free radicals that subsequently initiated both graft‐ and homo‐polymerization of vinyl monomer such as n‐butyl acrylate, methyl methacrylate, and styrene. Stable particles in the range from 100 to 250 nm in diameter with very narrow size distributions (polydispersity index between 1.08 and 1.15) were produced in high yields. TEM images of the particles revealed that they had well‐defined core–shell nanostructures with thick and hairy PVAm shells. The structures of the vinyl monomer and water‐soluble polymer were found to strongly influence the formation of particles and their sizes.

     

A new soluble conducting polymer and its electrochromic devices

A new polythiophene derivative was synthesized by both chemical and electrochemical oxidative polymerization of 1‐(1‐phenylethyl)‐2,5‐di(2‐thienyl)‐1H‐pyrrole (PETPy). Of which the chemical method produces a polymer that is completely soluble in organic solvents. The structures of both the monomer and the soluble polymer were elucidated by nuclear magnetic resonance (¹H and ¹³C NMR) and Fourier transform infrared (FTIR) spectroscopy. The average molecular weight has been determined by gel permeation chromatography to be M_n = 3.29 × 10³ for the chemically synthesized polymer. Polymer of PETPy was synthesized via potentiostatic electrochemical polymerization in acetonitrile (AN)/NaClO₄/LiClO₄ (0.1 M) solvent–electrolyte couple. Characterizations of the resulting polymer were performed by cyclic voltammetry, FTIR, scanning electron microscopy, and UV–vis spectroscopy. Four‐probe technique was used to measure the conductivities of the samples. Moreover, the spectroelectrochemical and electrochromic properties of the polymer films were investigated. In addition, dual‐type polymer electrochromic devices based on P(PETPy) with poly(3,4‐ethylenedioxythiophene) were constructed. Spectroelectrochemistry, electrochromic switching, and open circuit stability of the devices were studied. They were found to have good switching times, reasonable contrasts, and optical memories. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2215–2225, 2006     

A new donor–acceptor double‐cable carbazole polymer with perylene bisimide pendant group: Synthesis,electrochemical, and photovoltaic properties

We report here electrochemical synthesis of novel soluble donor–acceptor (D–A) polymer with suitably functionalized perylenetetracarboxylic diimide dye derivative covalently linked to carbazole moiety (Cbz‐PDI). The band gap, E_g was measured using UV–Vis spectroscopy and compared with that obtained by cyclic voltammetry (CV). Efficient intramolecular electron transfer from carbazole‐donor to perynediimide‐acceptor leads to remarkable fluorescence quenching of the perylene core. Furthermore, spectroelectrochemical property and surface morphology of the polymer film were investigated. Characteristic monoanion and dianion radical bands on the UV–Vis absorption spectra attributed to the electrochemical reduction of the neutral polymer were observed. During the reduction process, red color of the film turned into blue and violet, respectively. Finally, the photovoltaic performance of the D–A double‐cable polymer was checked and nearly 0.1% electrical conversion efficiency is obtained under simulated AM 1.5 solar light with 100 mW/cm² radiation power. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 6280–6291, 2009     

Polycyclic arene‐based D–A polyimide electrets for high‐performance n‐type organic field effect transistor memory devices

We report the memory characteristics of n‐type N,N′‐bis(2‐phenylethyl)‐perylene‐3,4:9,10‐tetracarboxylic diimide‐based organic field‐effect transistors (OFET) using a series of donor–acceptor (D–A) polyimide electrets of poly[4,4′‐diamino‐4″‐methyltriphenylamine‐hexafluoroisopropylidenediphthal imide] ( PI(AMTPA‐6FDA) ), poly[N,N‐bis‐(4‐aminophenyl)‐aminonaphthalene‐hexafluoroisopropylidenediphthalimide] ( PI(APAN‐6FDA) ), and poly[N,N‐bis‐(4‐aminophenyl)‐aminopyrene‐hexafluoroisopropylidenediphthalimide] ( PI(APAP‐6FDA) ). Among the polymer electrets, the OFET memory device based on PI(APAP‐6FDA) exhibits the largest memory window of 40.63 V and the best charge retention ability (maintained for over 10⁴ s with the ON/OFF current ratio about 10³) due to introducing polycyclic arene functionality of pyrene into the electron donating moiety. With the excellent carrier delocalization, pyrene successfully enhanced the charge storage ability and sustained the CT complex. Besides, PI(APAP‐6FDA)‐based OFET memory also performed well in the write‐read‐erase‐read tests for over 100 cycles. Our finding may provide a new approach for the preparation of high performance nonvolatile OFET memories with electrets of D–A polyimide systems. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 139–147     

A new room‐temperature liquid,high‐performance tricyanate ester

A new tricyanate ester monomer of a tris(4‐hydroxyphenyl)benzene derivative was synthesized in 6‐steps with a 63% overall yield. The geminal substitution of phenyl rings on ethane, in addition to the creation of a racemic/diastereomeric mixture, resulted in a liquid monomer whereas compounds with similar structure and symmetry have melting points typically over 100 °C. Key properties of the polycyanurate, such as the glass transition temperature and moisture resistance, were positively influenced by the higher crosslink density provided by the monomer. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Preparation of a Porous polymer by a catalyst‐free diels‐alder reaction and its structural modification by post‐reaction

A microporous polymer is prepared by a catalyst‐free Diels–Alder reaction. A cyclopentadiene with both a diene and a dienophile functionality and a dienophilic maleimide are used for the Diels–Alder reaction. 1,3,5‐Tris(bromomethyl)‐2,4,6‐trimethylbenzene is reacted with sodium cyclopentadienide to produce the multicyclopentadiene‐functionalized monomer. A crosslinked polymer ( CDAP ) is obtained by the reaction of the cyclopentadiene monomer with N,N′‐1,4‐phenylenedimaleimide. The thermal dissociation of the cyclopentadiene dimeric unit and the subsequent Diels–Alder reaction with the maleimide group are investigated by the model reaction. We are able to restructure the crosslinked polymer network by taking advantage of the thermal reversibility of the Diels–Alder linkage. After the post thermal treatment, the BET surface area of the polymer ( CDAP‐T ) is greatly increased from 317 to 1038 m² g^?1. CDAP‐T is functionalized with pyrene by bromination with N‐bromosuccinimide and the subsequent substitution reaction with aminopyrene. The adsorption property of the pyrene‐functionalized polymer for an aromatic dye is investigated using malachite green. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 3646–3653     

Donor–acceptor copolymers for red‐ and near‐infrared‐emitting polymer light‐emitting diodes

We report a comparative study of two organic soluble, vinylene‐based, alternating donor–acceptor copolymers with 1,4‐(2,5‐dihexadecyloxyphenylene) as the donor; the acceptor is either a 2,5‐linked pyridine or a 5,8‐linked 2,3‐diphenylpyrido[3,4‐b]pyrazine. The polymers are synthesized via a Heck coupling methodology from a dihalo monomer and a divinyl monomer to yield number‐average molecular weights of 16,000 g/mol for the pyridine polymer (PPyrPV) and 6500 g/mol for the pyridopyrazine polymer (PPyrPyrPV), with high solubility in common chlorinated solvents and lower solubility in less polar solvents (e.g., tetrahydrofuran). Thin‐film measurements show band gaps of 2.2 and 1.8 eV for PPyrPV and PPyrPyrPV, respectively. Both polymers exhibit photoluminescence in solution and in the solid state and exhibit electroluminescence when incorporated into light‐emitting diodes. In this case, a broad red emission centered at 690 nm for PPyrPV and a near‐infrared emission centered at 800 nm for PPyrPyrPV have been observed. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1417–1431, 2005     

Synthesis,structure, and properties of polyimide and polyurethane‐urea‐imide copolymers

Several, novel polyimide–polyurethane‐urea‐imide (PI‐PUI) copolymers with different polyimide (PI) contents were prepared by an in situ interpenetrating reaction between polyurethane‐urea‐imide (PUI) precursor and poly(amide acid). Changing the ratio of the PUI precursor and poly(amide acid) resulted in a change of the properties of the PI‐PUI copolymers from plastic to elastomer. Fourier transform infrared spectra revealed the characteristic absorption bands of PI‐PUI copolymers; differential scanning calorimetry (DSC) analyses revealed that the glass‐transition temperature of the soft‐segment‐rich phase decreased as the PI content increased in PI‐PUIs, meaning that the soft segments (i.e., PEG) were more incompatible and had better crystallizability with a high‐PI‐segment content in PI‐PUI. Wide‐angle X‐ray diffraction curves exhibited more ordered structure within the disordered PI‐PUI copolymer's state with an increasing PI content, which further agreed with the DSC results. Scanning electron micrographs clearly showed that the molecular chains in PI‐PUI with a high‐PI‐content packed, ordered lamellar structure. Thermogravimetric curves indicated that the heat resistance of PI‐PUI was better than pure PUI. The introduction of the PI component into PUI by an in situ interpenetrating reaction method is an effective way to improve the thermal stability and solvent resistance of PUI. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 216–225, 2004     

Poly(silarylene–siloxane)polyimides from allyl‐terminated oligoimides and hydride‐functional silarylene–siloxanes via hydrosilylation polymerization

This research was focused on the design and execution of new synthetic routes to low‐temperature‐curable poly(silarylene–siloxane)polyimides. The synthesis of individual oligoimide and silarylene–siloxane blocks was followed by hydrosilylation polymerization to produce crosslinked copolymers. The silarylene–siloxane and polyimide blocks were structurally characterized by IR and ¹H NMR spectroscopy and size exclusion chromatography. The high‐temperature resistance of the copolymers was evaluated through the measurement of heat distortion temperatures (T_HD's) via thermomechanical analysis and by the determination of the weight loss at elevated temperatures via thermogravimetric analysis. Glass‐transition temperatures (T_g's) of the silarylene–siloxane segments were measured by differential scanning calorimetry. Hydrosilylation curing was conducted at 60 °C in the presence of chloroplatinic acid (H₂PtCl₆). The copolymers displayed both high‐temperature resistance and low‐temperature flexibility. We observed T_g of the silarylene–siloxane segment as low as ?77 °C and T_HD of the polyimide segment as high as 323 °C. The influence of various oligoimide molecular weights on the properties of copolymers containing the same silarylene–siloxane was examined. The effect of various silarylene–siloxane molecular weights on the properties of copolymers containing the same oligoimide was also examined. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4922–4932, 2005     

N‐methylolmaleimide–benzene photoadduct: A novel monomer for the synthesis of functionally modified polyimides

A novel polycyclic dihydroxy diimide monomer was synthesized through the photocycloaddition of N‐methylolmaleimide to benzene and the reaction of maleimide–benzene photoadduct with formaldehyde. The monomer, which evolved formaldehyde at about 165 °C, was subsequently used to prepare low molecular weight polyamineimides and polyurethaneimides. Soluble polyamineimides, prepared with three different aromatic diamine monomers, exhibited initial decomposition temperatures between 277 and 329 °C and glass‐transition temperatures between 180 and 219 °C. An aliphatic polyamineimide prepared from 1,6‐hexanediamine was insoluble and had glass‐transition and initial decomposition temperatures of 225 °C and 294 °C, respectively, with prior loss of formaldehyde from end groups. Polyurethaneimides prepared with two aromatic diisocyanates showed loss of formaldehyde in the approximate range of 160–169 °C followed by loss of CO₂ and glass‐transition temperatures of 219 and 233 °C. Attempts to prepare polyamideimides resulted in oligomers with a low nitrogen content. Attempts to prepare polyesterimides were unsuccessful. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 2645–2651, 2000     

Active role of hydrogen bond and ambient water in Meyer–Schuster rearrangements in high‐temperature water

Meyer–Schuster rearrangements of 2‐phenyl‐3‐butyn‐2‐ol with H₃O⁺ and (H₂O)₆ model in high‐temperature water (HTW) have been investigated by the use of density functional theory calculations. In the substrate 2‐phenyl‐3‐butyn‐2‐ol catalyzed by H₃O⁺ and (H₂O)₆, the Meyer–Schuster rearrangements were predicted by the frontier molecular orbital theory. The results show that the rearrangement does not involve the carbonium ion intermediates, but the first transition state is carboniumion like. Dehydration and hydration may occur via the intermolecular proton relay along the hydrogen‐bond chains and the second step of reaction path is a total acid–base catalytic process. Based on the results, a model considered both HTW ambient and water molecules are proposed to represent mechanisms of other reactions in HTW. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2011