Synthesis and characterization of polyimides based on isopropylidene-containing bis(ether anhydride)s

Two bis(ether anhydride)s, 4,4′-[1,4-phenylenebis(isopropylidene-1,4-phenyleneoxy)]-diphthalic anhydride (IV _a) and 4,4′-[isopropylidenebis(1,4-phenylene)dioxy]diphthalic anhydride (IV _b), were prepared in three steps starting from the nucleophilic nitrodisplacement reaction of 4-nitrophthalonitrile with α,α ′-bis(4-hydroxyphenyl)-1,4-diisopropylbenzene (I _a) and 4,4′-isopropylidenediphenol (I _b) in N,N-dimethylformamide (DMF) in the presence of potassium carbonate. The bis(ether anhydride)s IV _a and IV _b were polymerized with various aromatic diamines to obtain two series of poly(ether amic acid)s VI _a–g and VII _a–g with inherent viscosities in the range of 0.30∼0.74 and 0.29∼1.01 dL/g, respectively. The poly(ether amic acid)s were converted to poly(ether imide)s VIII _a–g and IX _a–g by thermal cyclodehydration. Most of the poly(ether imide)s could afford flexible and tough films, and they showed high solubility in polar solvents such as N-methyl-2-pyrrolidone (NMP), N,N-dimethylacetamide, and m-cresol. The obtained poly(ether imide) films had tensile strengths of 45∼83 MPa, elongations-to-break of 6∼27%, and initial modulus of 0.6∼1.7 GPa. The T_gs of poly(ether imide)s VIII _a–g and IX _a–g were in the range of 194∼210 and 204∼243 °C, respectively. Thermogravimetric analysis (TG) showed that 10% weight loss temperatures of all the polymers were above 500 °C in both air and nitrogen atomspheres.     

Synthesis and properties of aromatic polyimides based on ether-sulfone-diamines

Two diamine monomers, 4,4′-[sulfonylbis(1,4-phenyleneoxy)]dianiline (III _a ) and 4,4′-[sulfonylbis(2,6-dimethyl-l,4-phenyleneoxy)]dianiline (III _b ), were prepared by an aromatic nucleophilic substitution of 4,4′-sulfonyldiphenol (I _a ) and 4,4′-sulfonylbis(2,6-dimethylphenol) (I _b ) with p-chloronitrobenzene in the presence of potassium carbonate, followed by hydrazine catalytic reduction of the intermediate dinitro compounds. The diamines III _a and III _b were used as monomers with various aromatic tetracarboxylic dianhydrides (IV _a–f ) to synthesize polyimides. The polymerization was conducted in two steps via the formation of a poly(amic acid) precursor followed by thermal cyclodehydration. The poly(amic acid)s had inherent viscosities above 0.87 and up to 2.56 dL/g. Most poly(amic acid)s could be coated and thermodehydrated into flexible and transparent polyimide films. The polyimides derived from the dianhydrides containing-O-and-SO₂-or-C(CF₃)₂-bridging groups between the phthalic anhydride units were soluble in some organic solvents such as N,N-dimethylacetamide (DMAc) and N,N-dimethylformamide (DMF). The glass transition temperatures (T_g) of the polyimides were in the range from 254 to 300 °C. The methyl-substituted polyimides exhibited slightly higher solubility and higher T_g compared to the corresponding unsubstituted polyimides. Thermogravimetric analysis (TG) showed that the polyimides containing methyl substitutents started to lose weight around 450 °C and the unsubstituted ones started to lose weight around 550 °C.     

Synthesis and properties of novel aromatic polyimides derived from bis(p-aminophenoxy)methylphenylsilane

A novel siloxane-containing diamine, bis(p-aminophenoxy)methylphenylsilane (BAMPS), was synthesized from the condensation of dichloromethylphenylsilane with p-aminophenol in the presence of triethylamine. A series of BAMPS-based aromatic polyimides were prepared from BAMPS and various aromatic tetracarboxylic dianhydrides by the usual two-step procedure including ring-opening polyaddition to poly(amic acid)s and subsequent cyclodehydration to polyimides. The inherent viscosities of poly(amic acid)s III_a - III_f ranged from 0.09 to 0.36 dL g⁻¹ in N,N-dimethylacetamide at a concentration of 0.5 g dL⁻¹ at 30°C. The inherent viscosities of polyimides were between 0.06 and 0.32 dL g⁻¹ in various solvents at 30°C. Polyimides, especially IV_c and IV_f , were soluble in a wide range of organic solvents such as N-methyl-2-pyrrolidinone, concentrated H₂SO₄, N,N-dimethylacetamide, N,N-dimethylformamide, and dimethyl sulfoxide. The polyimides were characterized by elementary analysis, IR spectra, TGA, and DSC. They also had glass transition temperatures ranging from 128 to 181°C. The 10% mass loss temperature was recorded in the range of 404–443°C in nitrogen and of 315–339°C in oxygen. © 1997 John Wiley & Sons, Inc.     

Polymeric molecular shuttles: Polypseudorotaxanes & polyrotaxanes based on viologen (paraquat) urethane backbones & bis(p-phenylene)-34-crown-10

Reaction of di(p-isocyanatophenyl)methane (MDI, 4) with N,N′-di(2-hydroxyethyl)- (1b) or N,N′-di[2-(2′-hydroxyethoxy)ethyl]-4,4′-bipyridinium di(hexafluorophosphate) (1e) and other diols [oligo(ethylene glycol)s and poly(tetramethylene oxide)s] in the presence of bis(p-phenylene)-34-crown-10 (2) afforded polyurethane (pseudo)rotaxanes as statistical (7P or 7R) and segmented analogs 10P (P = pseudorotaxane, R = rotaxane). In 7R a bulky alcohol was incorporated at the chain ends and in 13R a bulky diol as in-chain units to form polyrotaxanes and preclude the possibility of dethreading. The crown ether 2 in 10P and 13R was shown by ¹H NMR spectroscopy to be shuttling between the viologen (paraquat) and urethane sites; in DMSO the crown ether prefers the urethane site, probably because of H-bonding with the N–H moieties and complexation of the pyridinium site by the dipolar solvent, while in acetone at low temperatures the viologen site is preferred by the crown ether, with ΔH = −6.91 kcal/mol and ΔS = −22.9 eu for 13R.     

Chemical–physical properties of bis(perfluoroalkylsulfonyl)imide-based ionic liquids

The chemical–physical properties of hydrophobic ionic liquids, tailored as electrolyte components for supercapacitors and lithium batteries, were investigated and compared. The ionic liquid samples are based on bis(perfluroalkylsulfonyl)imide anions coupled with different types of cation. The effect of the cation as well as the main cationic aliphatic side group, in combination with different anions, on the chemical–physical properties of the investigated ionic liquid samples was evaluated and discussed. The activation energy for the conduction mechanism and the glass transition temperature were obtained by fitting the conductivity vs. temperature data.     

A comparison of poly(ether imide)s from diamines with 2-aminophenoxy or 4-aminophenoxy units: Synthesis, characterization and properties

A series of new 3- and 4-ring bis(2-aminophenoxy) aromatic diamines were prepared. These, and corresponding, conventional bis(4-aminophenoxy) diamines were reacted with several aromatic bis(ether anhydride)s to form poly(ether imide)s. The diamines with 4-aminophenoxy groups gave high-molecular-weight polymers that were cast into films with good mechanical properties. In contrast, in almost all cases, diamines with 2-aminophenoxy groups only gave low-molecular-weight powdery products that could not be cast into coherent films. The low-molecular-weight products, prepared from stoichiometrically equal amounts of monomers, were examined by mass spectrometry and shown, in most cases, to consist primarily of cyclic oligomers; traces of linear oligomers were identified in some samples. Apart from a polyimide prepared from pyromellitic dianhydride and 4,4′-bis(2″-aminophenoxy)biphenyl, the only products found to contain significant proportions of linear oligomers were those prepared with a stoichiometric imbalance of monomers. End groups of the various linear oligomers were identified. The 2-aminophenoxy groups predispose the oligomers to cyclize as amic acids, and to remain as cyclics on imidization. In some cases [1+1] cyclic oligomers were observed although the most common species were the [2+2] cyclic dimers.     

Synthesis and properties of soluble polyimides based on isomeric ditrifluoromethyl substituted 1,4-bis(4-aminophenoxy)benzene

A new fluorinated diamine monomer, [1,4-bis(4-amino-3-trifluoromethylphenoxy)benzene (2)], and a known isomeric analog 1,4-bis(4-amino-2-trifluoromethylphenoxy)benzene (3) were synthesized. A series of organosoluble polyimides Ia–d and IIa were prepared from the diamines (2, 3) and dianhydrides (a–d) by a high-temperature one-step method. The effects of the trifluoromethyl substituents on the properties of polyimides were evaluated through the study of their soluble, thermal, optical, and gas permeability properties. Polyimides (Ia–d) had glass transition temperatures between 229 and 279 °C, and the temperatures at 5% weight loss ranged from 510 to 533 °C under nitrogen. These polyimides could be cast into flexible and tough membranes from DMAc solutions. The membranes had tensile strengths in the range of 137–169 MPa, tensile modulus in the range of 1.6–2.2 GPa and elongations at break from 11% to 14%. The polyimide Ia with trifluoromethyl groups ortho to the imide nitrogen exhibited enhanced gas permeability, solubility, transparency, and thermal stability compared with the isomeric polyimide IIa with the CF₃ group meta to the imide nitrogen. Thus, the effect of substituents in the ortho-positions of nitrogen on properties was greater than the effect of substituents in the meta-positions.     

Alternate poly(amide-imide)s based on 1,4-and 1,3-bis(4-trimellitimido)benzene and their mixtures

Several series of alternate poly(amide-imide)s [P(A-alt-I)s] were synthesized by aromatic dicarboxylic acid (I- p or I- m), which was prepared by the condensation of p-phenylenediamine (or m-phenylenediamine), trimellitic anhydride, and various aromatic diamines by means of direct polycondensation. A diimide-diacid (I- p) with a p-phenylene group was used to synthesize P(A-alt-I)s III, and P(A-alt-I)s IV were synthesized by a diimide-diacid (I- m) prepared from m-phenylenediamine. Another series of P(A-alt-I)s V was synthesized from both I- p and I- m (1/1 mole) with various diamines. Polymers of series III have low inherent viscosities and limited solubility, but polymers of series IV have high degrees of polymerization. Series V copolycondensated from I- p and I- m has improved solubility and degrees of polymerization relative to series III. The degree of crystallinity was found to be III > V > IV. Glass transition temperatures for most of series III were not observed below 400 °C, and those of series IV and V were in the range of 238–325 °C and 262–328 °C, respectively. The 10% weight loss temperatures in nitrogen or in air of these three series are all in the range of 482–582 °C. Because series V has limited solubility for casting into films from DMAc solutions, two diamines were selected to synthesize series VI by changing the I- p/I- m ratio. Solubility was improved when the content of I- p in diimide-diacid was less than 15%, and the degree of crystallinity reduced as the content of I- p in diimide-diacid decreased. Polymers containing a few I- p showed an increase in the initial modulus.     

Ionic liquids and plastic crystals based on tertiary sulfonium and bis(fluorosulfonyl)imide

A new series of low-melting, low-viscosity, hydrophobic ionic liquids based on relatively small tertiary sulfonium cations ([R¹R²R³S]⁺, wherein R¹, R², R³ = CH₃ or C₂H₅, R³ = CH₂CH₂OCH₃, CH₂CH₂COOCH₃, CH₂CH₂CN) and bis(fluorosulfonyl)imide (FSI⁻) anion have been prepared and characterized. The important physicochemical and electrochemical properties of these salts, such as melting point, glass transition, viscosity, density, ionic conductivity, thermal and electrochemical stability, have been determined. The influence of structure variation in the tertiary sulfonium cations on the above physicochemical properties is discussed. Among these new salts, some of them show the desirable properties including low-melting points, low viscosities, and high conductivities, to be selected as potential candidates as electrolytes in energy devices, and two salts are ionic plastic crystals.     

Syntheses and Structural Characterization of Co(II) Coordination Polymers Supported by Bis(<Emphasis Type="Italic">N</Emphasis>-benzimidazolyl)methane and Bis(<Emphasis Type="Italic">N</Emphasis>-imidazolyl)methane

[Co₂(L¹)₂(NCS)₄]·4MeOH 1, [Co(L²)₂(H₂O)₂](Sal)₂·4H₂O (Sal = salicylate) 2 were obtained from self-assembly of the cobalt salts with bis(N-benzimidazolyl)methane (L¹), and bis(N-benzimidazolyl)methane (L²), and their structures were characterized by IR and X-ray diffraction analysis. Complex 1 exhibits a two-dimensional grid structure, whereas complex 2 is a coordination polymer having a one-dimensional linear chain structure. The grid in 1 lies parallel to the crystallographic ab plane and exhibits intra-grid M–M separations of 10.508 × 10.508 Å. Hydrogen bonds hold the cationic chains in 2 together leading to a three-dimensional network structure.     

Electrochemical properties of alkali bis(trifluoromethylsulfonyl)amides and their eutectic mixtures

Densities, viscosities and ionic conductivities of single salts and the binary eutectic mixtures of alkali bis(trifluoromethylsulfonyl)amides, MTFSAs (M = Li, Na, K, Rb, Cs), were measured in the temperature range of 413-573 K. Cyclic voltammetry revealed that the binary eutectic melts have wide electrochemical windows of 5.0-6.0 V. It was found that alkali metals reversibly deposit on a nickel electrode at the cathode limit potentials. The order of the deposition potential was determined to be Na > Li > (K, Rb, Cs).     

Novel bis(benzoin) titanium catalyst for homo- and copolymerization of norbornene with ethylene: Synthesis, characterization and catalytic properties

A novel titanium(IV) dimeric complex [(OC(Ph)HC(Ph)O)TiCl(μ-OCH(Ph)C(Ph)(n-Bu)O)]₂ (1) was synthesized and characterized, and its catalytic behaviors toward homo- and copolymerization of ethylene (E) and norbornene (NB) were also investigated. X-ray diffraction analysis of single crystal structure revealed that the titanium complex features a binuclear and six-coordinate, pseudo-octahedral geometry around titanium metal center with oxo-bridge in the solid state. Activated with methylalumoxane (MAO), the titanium complex exhibited good activities for the homopolymerizations of ethylene and norbornene with long lifetime and produced high-molecular weight linear PE and vinyl-type PNB, respectively. E-NB copolymers with high-molecular weight and high NB incorporation content could be also obtained by this catalyst. The incorporation of NB in the E-NB copolymers could be controlled by varying monomer ratio and reaction temperature. ¹³C NMR analyses showed that the microstructures of the E-NB copolymers are predominantly alternated and isolated NB units, but the dyad and triad sequences of NB unit could be detected in the copolymers with high NB incorporation. The monomer reactivity ratios of the copolymerization were measured to be r_E = 6.0, r_N = 0.05 at 30 °C.     

Structural characterization and luminescent properties of poly(p-phenylene vinylene) and poly(ethylene glycol) blends

The luminescent properties of poly(p-phenylenevinylene) (PPV) blending with poly (ethylene glycol) (PEG) were investigated in terms of their structural formation during sample preparation. The blended systems were prepared from an aqueous solution of water-soluble poly (xylylene tetrahydrothiophenium chloride) (PPV precursor) mixed with PEG, followed by heat treatment to remove the tetrahydrothiophene groups from the PPV precursor. Structural analysis showed that PEG could react with PPV precursor to form C-O-C linkage and carbonyl groups in PPV chains, interrupting their conjugated length as suggested by their Infrared, Raman and UV/vis spectroscopes. Wide angle X-ray scattering (WARS) of blended systems also showed that PPV in blends had less packing. As to luminescent properties, the UV/vis and photoluminescent (PL) spectra show that the energy gap needed to produce the excitons increased along with the increase of PL intensity when PPV was blended with PEG. Similar results were also found for the EL properties of ITO/polyblends/Al devices. The EL light emission from blends was blue-shifted (compared to PPV) with a rather low threshold electric field strength. The EL performance of polyblends was better than that of pure PPV. Among them, the PPV-50PEG showed the highest EL intensity. The improved EL efficiency was attributed to the dilution effect, interrupted conjugated length, and lower packing of PPV chains.     

Synthesis and electrochromic properties of aromatic polyimides bearing pendent triphenylamine units

A series of aromatic polyimides with pendent triphenylamine group were synthesized from equimolar mixtures of 4,4′-oxydianiline (ODA) and 4-(3,5-diaminobenzamido)triphenylamine (4), 4-(3,5-diaminobenzamido)-4′,4″-di-tert-butyltriphenylamine (t-Bu-4) or 4-(3,5-diaminobenzamido)-4′,4″-dimethoxytriphenylamine (MeO-4) with two aromatic tetracarboxylic dianhydrides (DSDA or 6FDA) via a conventional two-step procedure that included a ring-opening polyaddition to give poly(amic acid)s, followed by chemical imidization. These polyimides exhibited good solubility in polar organic solvents and could be solution-cast into flexible and strong films. They showed excellent thermal stability, with T_g values in the range of 284–309 °C. The polyimides derived from diamines t-Bu-4 and MeO-4 exhibited reversible electrochemical oxidation, accompanied by strong color changes with high contrast ratio and electrochromic stability. For the polyimides derived from diamine 4, the coupling reaction between the triphenylamine radical cations occurred during the oxidative process forming a tetraphenylbenzidine structure, which resulted in an additional oxidation state and color change together with enhanced near-IR absorption at fully oxidized state.     

Synthesis and crystal structures of copper(I) iodide complexes chelating with bis(ethylamidophosphine)

Two copper(I) iodide complexes with polydentate bis(ethylamidophosphine) ligands were synthesized, characterized with crystal structures. They include a dimeric complex [Cu(μ-I)(CH₂NHCOC₂H₄PPh₂)₂]₂ 1 containing a planar Cu₂I₂ rhombohedron with two doubly bridged ligands and a tetrameric complex {Cu₄(μ-I)₄[(CH₂NHCOC₂H₄PPh₂)₂]₂} 3 with all the coppers and iodines forming a highly distorted cubane geometry.     

Photosensitive poly(benzoxazole) based on precursor from diphenyl isophthalate and bis(o-aminophenol)

A new synthetic method for the preparation of poly(benzoxazole) (PBO) precursor, poly(o-hydroxyamide) (7) from bis(o-aminophenol) (5) and diphenyl isophthalate (6) has been developed. Polymer 7 was prepared by the polycondensation of 5 and 6 in 1-methyl-2-pyrrolidinone (NMP) at 185-205 °C. Model reactions were carried out in detail to elucidate appropriate conditions for the formation of 2-hydroxybenzanilide (3) from o-aminophenol (1) and phenyl benzoate (2). The photosensitive (PBO) precursor based on polymer 7 containing a 22% of benzoxazole unit and 30 wt% 1-{1,1-bis[4-(2-diazo-1-(2H)naphthalenone-5-sulfonyloxy)phenyl]ethyl}-4-{1-[4-(2-diazo-1(2H)naphthalenone-5-sulfonyloxy)phenyl]methylethyl}benzene (S-DNQ) showed a sensitivity of 110 mJ cm⁻² and a contrast of 5.0 when it was exposed to 436 nm light followed by developing with a 2.38 wt% aqueous tetramethylammonium hydroxide solution at room temperature. A fine positive image featuring 8 μm line and space patterns was observed on the film of the photoresist exposed to 200 mJ cm⁻² of UV-light at 436 nm by the contact mode.     

Syntheses and thermal properties of poly(hydroxy)urethanes by polyaddition reaction of bis(cyclic carbonate) and diamines

In this study, we synthesized poly(hydroxy)urethanes by the polyaddition reaction of bis(cyclic carbonate) and diamine. Bis(cyclic carbonate) was prepared from diglycidyl ether based on bisphenol S and carbon dioxide. Thermal properties and solubilities of the poly(hydroxy)urethanes of five different diamines were compared. The thermal properties of the poly(hydroxy)urethanes depended on the structure of the diamine as well as the structure of the monomer. These poly(hydroxy)urethanes were soluble only in aprotic solvents because of the hydrophilic character of the hydroxy group. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2735–2743, 2001     

Synthesis and properties of organosoluble polyimides based on 2,2′-diphenoxy-4,4′,5,5′-biphenyltetracarboxylic dianhydride

A novel method for the preparation of 2,2′-diphenoxy-4,4′,5,5′-biphenyltetracarboxylic dianhydride have been investigated. This new dianhydride contains flexible phenoxy side chain and a twist biphenyl moiety and it was synthesized by the nitration of an N-methyl protected 3,3′,4,4′-biphenyltetracarboxylic dianhydride and subsequent aromatic nucleophilic substitution with phenoxide. The overall yield was up to 75%. The dianhydride was polymerized with five different aromatic diamines to afford a series of aromatic polyimides. The polyimide properties such as inherent viscosity, solubility, UV transparency and thermaloxidative properties were investigated to illustrate the contribution of the introduction of phenoxy group at 2- and 2′-position of BPDA dianhydride. The resulting polyimides possessed excellent solubility in the fact that the polyimide containing rigid diamines such as 1,4-phenylenediamine and 4,4′-oxydianiline were soluble in various solvents such as N-methyl-2-pyrrolidone, N,N-dimethylacetamide, dimethyl sulfoxide and chloroform. The glass-transition temperatures of the polymers were in the range of 255-283 °C. These polymers exhibited good thermal stability with the temperatures at 5% weight loss range from 470 to 528 °C in nitrogen and 451 to 521 °C in air, respectively. The polyimide films were found to be transparent, flexible, and tough. The films had a tensile strength, elongation at break, and Young's modulus in the ranges 105-168 MPa, 15-51%, 1.87-2.38 GPa, respectively.     

二（2—苯并咪唑亚甲基）胺配合物的合成

本文论述了二（２－苯并咪唑亚甲基）胺及配合物的合成方法,并对配合物进行了元素分析,为研究ＳＯＤ提供了基础和数据。     

Anodic oxidation of bis(organylchalcogeno)acetylenes

The electrochemical oxidation of bis(organylchalcogeno)acetylenes has been examined in organic solvents. With symmetrical ones, R---Z---CC---Z---R (1) (Z=S, Se), and with unsymmetrical ones, R¹---S---CC---Z---R² (2) (Z=Se), in macroscale electrolyses the α-diesters R¹---Z(S)---CO---CO---Z---R² were obtained as the main products. If Z=Te, from 1 and 2, reactions were more complex and the cleavage of the C---Te bond was always observed.