Preparation and properties of organo‐soluble polyimides based on 4,4′‐diamino‐3,3‐dimethyldiphenylmethane and conventional dianhydrides

4,4′‐Diamino‐3,3′‐dimethyldiphenylmethane was used to prepare polyimides in an attempt to achieve good organo‐solubility and light color. Polyimides based on this diamine and three conventional aromatic dianhydrides were prepared by solution polycondensation followed by chemical imidization. They possess good solubility in aprotonic polar organic solvents such as N‐methyl 2‐pyrrolidone, N,N‐dimethyl acetamide, and m‐cresol. Polyimide from 4,4′‐diamino‐3,3′‐dimethyldiphenylmethane and diphenylether‐3,3′,4,4′‐tetracarboxylic acid dianhydride is even soluble in common solvents such as tetrahydrofuran and chloroform. Polyimides exhibit high transmittance at wavelengths above 400 nm. The glass transition temperature of polyimide from 4,4′‐diamino‐3,3′‐dimethyldiphenylmethane and pyromellitic dianhydride is 370°C, while that from 4,4′‐diamino‐3,3′‐dimethyldiphenylmethane and diphenylether‐3,3′,4,4′‐tetracarboxylic acid dianhydride is about 260°C. The initial thermal decomposition temperatures of these polyimides are 520–540°C. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 1299–1304, 1999     

Synthesis and characterization of polyetherimides containing multiple ether linkages and pendent pentadecyl chains

4‐(4‐(4‐(4‐Aminophenoxy)‐2‐pentadecylphenoxy)phenoxy)aniline (APPPA) was synthesized starting from cashew nut shell liquid‐derived bisphenol, i.e. 4‐(4‐hydroxyphenoxy)‐3‐pentadecylphenol, by nucleophilic substitution reaction with 4‐chloronitrobenzene followed by reduction of the formed 4‐(4‐nitrophenoxy)‐1‐(4‐(4‐nitrophenoxy)phenoxy)‐2‐pentadecylbenzene. Three new polyetherimides containing multiple ether linkages and pendent pentadecyl chains were synthesized by one‐step high‐temperature solution polycondensation of APPPA in m‐cresol with three aromatic dianhydrides, i.e. 3,3′,4,4′‐oxydiphthalic anhydride, 4,4′‐(hexafluoroisopropylidene)diphthalic anhydride and 3,3′,4,4′‐biphenyltetracarboxylic dianhydride. Inherent viscosities and number‐average molecular weights of the polyetherimides were in the ranges 0.66–0.70 dL g^?1 and 17 100–29 700 g mol^?1 (gel permeation chromatography, polystyrene standards), respectively, indicating the formation of reasonably high molecular weight polymers. The polyetherimides were soluble in organic solvents such as chloroform, dichloromethane, tetrahydrofuran, pyridine, m‐cresol, N,N‐dimethylformamide, N,N‐dimethylacetamide, N‐methylpyrrolidone and dimethylsulfoxide, and could be cast into transparent, flexible and tough films from their solutions in chloroform. The polyetherimides exhibited glass transition temperatures (T_g) in the range 113–131 °C. The lowering of T_g could be attributed to the combined influence of flexibilizing ether linkages and pentadecyl chains which act as ‘packing‐disruptive’ groups. The temperature at 10% weight loss (T₁₀), determined from thermogravimetric analysis in nitrogen atmosphere, was in the range 460–470 °C demonstrating good thermal stability. The virtues of solubility and large gap between T_g and T₁₀ mean that the polyetherimides containing pendent pentadecyl chains have possibilities for both solution as well as melt processability. © 2015 Society of Chemical Industry     

Synthesis and characterization of poly(acrylate amic acid) and its application as negative‐tone photosensitive polyimides

The dianhydride monomer 3,3′,4,4′‐benzophenone tetracarboxylic acid dianhydride and two diamine monomers, 4,4′‐diamino‐3,3′‐biphenyldiol (HAB) and 2,4‐diaminophenol dihydrochloride (DAP), were used to synthesize a series of poly(hydroxyl amic acid). Further functionalization by grafting acrylate groups yields the corresponding poly(acrylate amic acid) that underwent a crosslinking reaction on exposure to UV‐light and was used as a negative‐tone photosensitive polyimide (PSPI). The analysis of chemical composition and molecular weight of these poly(amic acid)s determined by nuclear magnetic resonance (NMR) spectroscopy, Fourier transform infrared spectroscopy, and gel permeation chromatography revealed that the molecular weight of the poly(hydroxyl amic acid) increased with the molar content of HAB in the feedstock, because HAB exhibited higher polymerization reactivity than DAP. Moreover, the degree of grafting acrylate groups onto poly(hydroxyl amic acid) was determined by ¹H‐NMR spectroscopy. The photoresist was formulated by adding 2‐benzyl‐2‐N,N‐dimethylamino‐1‐(4‐morpholinophenyl) butanone (IRG369) and isopropylthioxanthone as a photoinitiator, tetra(ethylene glycol) diacrylate as a crosslinker, and tribromomethyl phenyl sulfone as a photosensitizer. The PSPI precursor exhibited a photosensitivity of 200 mJ/cm² and a contrast of 1.78. A pattern with a resolution of 10 μm was observed in an optical micrograph after thermal imidization at 300°C. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Preparation and characterization of soluble copoly(aryl ether ketone)s containing hindering structures

New copoly(aryl ether ketone)s have been synthesized by polycondensation of 2,2′,3,3′,6,6′‐hexaphenyl‐4,4′‐diphenol, 2,2′‐p‐hydroxyphenyl‐iso‐propane, and 4,4′‐difluorobenzophenone. The technology of ¹³C‐NMR was used to determine contents of the two bisphenols in the copolymers. Chain structure was characterized by illustrating average block length (L_A, L_C) in terms of portion of the triads (AKA, CKC, AKC). The obtained copoly(aryl ether ketone)s have the properties of excellent solubility, high heat‐resistance, good tensile strength, and good selectivity for gas permeability. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 20–24, 2000     

Synthesis and characterization of new soluble poly(ester‐imide)s containing noncoplanar 2,2′‐dimethyl‐4,4′‐biphenylene unit

A new diimide–diacid chloride (3) containing a noncoplanar 2,2′‐dimethyl‐4,4′‐biphenylene unit was synthesized by treating 2,2′‐dimethyl‐4,4′‐diamino‐biphenylene with trimellitic anhydride followed by refluxing with thionyl chloride. Various new poly(ester‐imide)s were prepared from 3 with different bisphenols by solution polycondensation in nitrobenzene using pyridine as hydrogen chloride quencher at 170°C. Inherent viscosities of the poly(ester‐imide)s were found to range between 0.31 and 0.35 dL g^?1. All of the poly(ester‐imide)s, except the one containing pendent adamantyl group 5e, exhibited excellent solubility in the following solvents: N,N‐dimethylformamide, tetrahydrofuran, tetrachloroethane, dimethyl sulfoxide, N,N‐dimethylacetamide, N‐methyl‐2‐pyrrolidinone, m‐cresol, o‐chlorophenol, and chloroform. The polymers showed glass‐transition temperatures between 166 and 226°C. The 10% weight loss temperatures of the poly(ester‐imide)s, measured by TGA, were found to be in the range between 415 and 456°C in nitrogen. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2486–2493, 2004     

Synthesis of novel optically active poly(ester‐imide)s with benzophenone linkages by microwave‐assisted polycondensation

A new simple and rapid polycondensation reaction of 4,4′‐carbonyl‐bis(phthaloyl‐L ‐alanine)diacid chloride [N,N ′‐(4,4′‐carbonyldiphthaloyl)]bisalanine diacid chloride with several diphenols, such as bisphenol‐A, phenolphthalein, 1,8‐dihydroxyanthraquinone, 4,4′‐dihydroxybiphenyl, 1,5‐dihydroxynaphthalene and hydroquinone, in the presence of a small amount of a polar organic medium such as o‐cresol was performed using a domestic microwave oven. The polycondensation reaction proceeded rapidly and was almost complete within 12 min to give a series of poly(ester‐imide)s with inherent viscosities of about 0.35–0.58 dl g⁻¹. The resulting poly(ester‐imide)s were obtained in high yield and are optically active and thermally stable. All the above compounds have been fully characterized by IR spectroscopy, elemental analysis, inherent viscosity (η_inh), solubility test and specific rotation. Thermal properties of the poly(ester‐imide)s have been investigated using thermal gravimetric analysis (TGA). © 2000 Society of Chemical Industry     

Disecondary amine synthesis and its reaction kinetics with epoxy prepolymers

3,3′‐Diaminodiphenyl sulfone (3,3′‐DDS) was reacted with acetaldehyde in the presence of sodium triacetoxy borohydride via reductive amination to yield a 3,3′‐DDS based secondary diamine, N,N′‐diethyl‐3,3′‐diaminodiphenyl sulfone. Near IR analysis indicated that the 5060 cm^?1 peak for primary amine (? NH₂) in 3,3′‐DDS was absent in the reaction product spectrum. The ? NH₂ proton peak at δ 5.66 ppm shifted to δ 6.16 ppm in the product. Methyl and methylene protons of CH₃? CH₂? NH? Ph? group were observed at δ 3.01 and 1.12 ppm, respectively, in the product. The carbon NMR spectrum of the reaction product showed new peaks at δ 37.46 and 14.47 ppm that further confirmed secondary amine formation. The liquid chromatography coupled mass spectra peaks at 248–250 for 3,3′‐DDS and 304 for the reaction product further supported the formation of N,N′‐diethyl‐3,3′‐diaminodiphenyl sulfone. A blend of N,N′‐diethyl‐3,3′‐diaminodiphenyl sulfone with diglycidyl ether of bisphenol‐A (DGEBA) epoxy prepolymer started reacting at about 110–125°C surpassing an energy barrier of ～ 66 kJ/mol as determined via differential scanning calorimetry analysis. Reaction kinetics were characterized via near IR spectroscopy specific to the reaction between secondary amine and DGEBA epoxy prepolymer. The results confirmed >97% conversion at a cure protocol of 5 h at 80°C, 5 h at 100°C, 11 h at 125°C, and 6 h at 185°C. N,N′‐diethyl‐3,3′‐diaminodiphenyl sulfone‐DGEBA thermoplastics displayed tensile and flexural modulii of 3.08 and 2.86 GPa, respectively, and glass transition temperature (T_g) of 120.77°C. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Studies on Micellar Behavior of PEO‐PBO or PEO‐PBO‐PEO Copolymers,or Surface Active Amphiphilic Ionic Liquids in Aqueous Media and Exploration of the Micellar Solutions for Solubilization of Dexamethasone and its Delayed Release

The aggregation behavior of a di‐ and tri‐block copolymers of type PEO‐PBO, PEO‐PBO‐PEO, surface‐active ionic liquid (SAIL) of type 4‐dodecyl‐4‐methylmorpholinium chloride [C₁₂mmor][Cl], and 1‐dodecyl‐1‐methylpyrrolidinium chloride [C₁₂mpyrr][Cl]) in water as well as in 10 mM of a poorly water soluble dexamethasone (dex) aqueous solution was studied by determining the critical micelle concentrations using drug solubilization, surface tension, and isothermal titration calorimetry (ITC) methods. ITC measurements were also made on solutions prepared by mixing the micellar aqueous solutions of copolymers and simple aqueous solutions of SAIL across the mole fractions at three different temperatures (298.15, 308.15, and 318.15 K). The thermodynamic parameters, namely Gibbs free energy (ΔG_m), enthalpy (ΔH_m), and entropy (ΔS_m), of micellization were calculated, and it was observed that the negative ΔG_m and positive ΔS_m for the mixture solutions increase with the increase in mole fraction of SAIL. Otherwise, the micellization is reported to be a spontaneous and highly entropy‐driven process. The dex‐solubilized micellar solutions were mixed with agar to obtain standing gels. The gel samples were dry‐cast into thin films, and the release of dex from films by simple dilution was monitored by UV measurements. The drug release data was fitted to several mechanistic models, and it was inferred that the release mechanism for dex from thin films is non‐Fickian for mixtures and Fickian in copolymer or SAIL micellar aqueous solutions. The transport of dex is diffusion‐controlled with diffusivities of 5.8–12 × 10^?11 m² s^?1 for copolymer micelles, 5–11 × 10^?11 m² s^?1 for micelles of SAIL, and 3–14 × 10^?11 m² s^?1 for the mixed micelles of copolymer and SAIL in aqueous media.     

Synthesis and characterization of cross‐linkable poly(phthalazinone ether ketone)s

A novel class of crosslinkable poly(phthalazinone ether ketone)s with relative high molecular‐weight and good solubility were successfully synthesized by the copolymerization of bisphthalazinone containing monomer, 3,3′‐diallyl‐4,4′‐dihydroxybiphenyl and 4,4′‐di‐ fluorobenzophenone. The synthesized polymers with inherent viscosities in the range of 0.42 to 0.75 dL/g can form flexible and transparent membranes by casting from their solution. The crosslinking reaction of these polymers can be carried out by thermally curing of the virgin polymers in or without the presence of crosslinking agent. The experimental results demonstrated that the crosslinking reaction also occurred to some extent during the polymerization. The crosslinked polymers exhibited equivalent glass transition temperature (T_g) at lower crosslinking density, and showed higher T_g than virgin polymers at higher crosslinking density. The crosslinked high‐temperature polymer can be used as the base material for high temperature adhesive, coating, enamel material, and composite matrices. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Insensitive High Explosives II: 3,3′‐Diamino‐4,4′‐azoxyfurazan (DAAF)

This paper reviews the synthesis, properties, performance, and safety of the insensitive explosive 3,3′‐diamino‐4,4′‐azoxyfurazan (DAAF, C₄H₄N₈O₃), CAS‐No. [78644‐89‐0], and 18 formulations based on it. Though having a moderate crystal density only, DAAF offers high positive heat of formation and hence superior performance when compared with TATB. It is friction and impact insensitive but is more sensitive to shock than TATB and has an exceptionally small critical diameter and performs very well at low temperatures unlike other insensitive explosives. 39 references to the public domain are given. For Part I see Ref. [1].     

Cure kinetics of ternary blends of epoxy resins studied by nonisothermal DSC data

The curing kinetics of blends of diglycidyl ether of bisphenol A (DGEBA), cycloaliphatic epoxy resins, and carboxyl‐terminated butadiene‐acrylonitrile random copolymer (CTBN) in presence of 4,4′‐diamino diphenyl sulfone (DDS) as the curing agent was studied by nonisothermal differential scanning calorimetry (DSC) technique at different heating rates. The kinetic parameters of the curing process were determined by isoconversional method given by Malek for the kinetic analysis of the data obtained by the thermal treatment. A two‐parameter (m, n) autocatalytic model (Sestak‐Berggren equation) was found to be the most adequate selected to describe the cure kinetics of the studied epoxy resins. The values of E_a were found to be 88.6 kJ mol^?1 and 61.6 kJ mol^?1, respectively, for the studied two sample series. Nonisothermal DSC curves obtained using the experimental data show a good agreement with that theoretically calculated. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis and characterization of new polyamides containing p‐phenylenediacryloyl moieties in the main chain

Six new polyamides 8a–f containing p‐phenylenediacryloyl moieties in the main chain were prepared by the direct polycondensation reaction of bis(p‐amidobenzoic acid)‐p‐phenylene diacrylic acid 6 with 1,4‐diphenylene diamine 7a , 1,3‐diamino toluene 7b , 1,5‐diamino naphthalene 7c , 4,4′‐diamino diphenyl ether 7d , 4,4′‐diamino diphenyl sulfone 7e , and 3,3′‐diamino diphenylsulfone 7f by using thionyl chloride, N‐methyl‐2‐pyrolidone, and pyridine as condensing agents. These new polymers 8a–f were obtained in high yield and inherent viscosity between 0.35–0.65 dL/g. The resulting polyamides were characterized by elemental analysis, viscosity measurements, thermal gravimetric analysis (TGA and DTG), solubility test, FTIR and UV–vis spectroscopy. Diacid acid 6 as a new monomer containing p‐phenylenediacryloyl moiety was synthesized by using a three‐step reaction. First, p‐phenylenediacrylic acid 3 was prepared by reaction of terephthal aldehyde 1 with malonic acid 2 in the presence of pyridine, then diacid 3 was converted to p‐phenylenediacryloyl chloride 4 by reaction with thionyl chloride. Finally, bis(p‐amidobenzoic acid)‐p‐phenylene diacrylic acid 6 was prepared by the condensation reaction of phenylenediacryloyl chloride 4 with p‐aminobenzoic acid 5 . © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Preparation and properties of thermally stable copolyimides based on novel second‐order nonlinear–optical chromophore containing diamines

Thermally stable copolyimides were prepared from two novel second‐order nonlinear optical chromophores containing diamines, 4‐nitro‐4′‐[N‐(4,6‐di‐β‐aminoethylamino)‐1,3,5‐triazin‐2‐yl]aminoazobenzene (M1) and 4‐nitro‐4′‐[N‐(4,6‐di‐4‐aminophenylamino)‐1,3,5‐triazin‐2‐yl]aminoazobenzene (M2); two codiamines, 4,4′‐diamino‐3,3′‐dimethyl diphenylmethane (MMDA) and bis‐(3‐aminopropyl)‐1,1′,3,3′‐tetramethyldisiloxane (SiDA); and 3,3′,4,4′‐diphenyl ether tetracarboxylic acid dianhydride (OPDA). All copolyimides possess high glass transition temperatures (T_g's) between 237 and 271°C. Copolyimides based on M2 do not exhibit an obvious change in T_g as the M2 content is increased, while those based on M1 show a slight decrease in T_g as the M1 content is increased. All copolyimides exhibit high thermal decomposition temperatures. The copolyimides are soluble in aprotic solvents such as NMP, DMAc, DMF, DMSO, and 1,4‐butyrolactone. Some are even soluble in common low boiling point solvents such as THF and chloroform. The refractive index of a copolyimide is increased as the chromophore content is increased, while the birefringence of a copolyimide does not exhibit strong dependence on the chromophore content. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 1619–1626, 2000     

Synthesis and characterization of novel borosiloxane‐containing aromatic copolyimides with excellent thermal stability and low coefficient of thermal expansion

The properties of borosiloxane‐containing copolyimides with borosiloxane in the main chain and in the side chain were studied. Two series of borosiloxane‐containing copolyimides were synthesized by the reaction of 3,3′,4,4′‐biphenyltetracarboxylic dianhydride (s‐BPDA ) and 2,3′,3,4′‐biphenyltetracarboxylic dianhydride (a‐BPDA ) with p ‐phenylenediamine (PDA ), 4,4′‐oxydialinine (4,4′‐ODA ) and different borosiloxane diamine monomers (BSiAs ). The synthesized borosiloxane‐containing copolyimides exhibited better solubility than borosiloxane‐free copolyimides and showed high glass transition temperatures (320–360 °C), excellent thermal stability (570–620 °C for T ₁₀), great elongation at break (10% ? 14%) and a low coefficient of thermal expansion (14–24 ppm °C^?1). More specifically, the copolyimides containing BSiA‐2 formed nano‐scale protrusions and the copolyimides containing BSiA‐1 formed micro‐scale protrusions. The contact angles of the copolyimides increased from 72° for neat copolyimide to 96° for 5% of borosiloxane in the main chain of the copolymer up to 107° for 10% of borosiloxane in the side chain of the copolymer. © 2017 Society of Chemical Industry     

Blue‐light‐emitting poly(arylene ethynylenes) containing alternating sequences of biphenylene or fluorenediyl and p‐phenylene moieties linked through triple bonds

Two new poly(arylene ethynylenes) were synthesized by the reaction of 1,4‐diethynyl‐2.5‐dioctylbenzene either with 4,4′‐diiodo‐3,3′‐dimethyl‐1,1′‐biphenyl or 2,7‐diiodo‐9,9‐dioctylfluorene via the Sonogashira reaction, and their photoluminescence (PL) and electroluminescence (EL) properties were studied. The new poly(arylene ethynylenes) were poly[(3,3′‐dimethyl‐1,1′‐biphenyl‐4,4′‐diyl)‐1,2‐ethynediyl‐(2,5‐dioctyl‐1,4‐phenylene)‐1,2‐ethynediyl] (PPEBE) and poly[(9,9‐dioctylfluorene‐2,7‐diyl)‐1,2‐ethynediyl‐(2,5‐dioctyl‐1,4‐phenylene)‐1,2‐ethynediyl] (PPEFE), both of which were blue‐light emitters. PPEBE not only emitted better blue light than PPEFE, but it also performed better in EL than the latter when the light‐emitting diode devices were constructed with the configuration indium–tin oxide/poly(3,4‐ethylenedioxythiophene) doped with poly(styrenesulfonic acid) (50 nm)/polymer (80 nm)/Ca:Al. The device constructed with PPEBE exhibited an external quantum efficiency of 0.29 cd/A and a maximum brightness of about 560 cd/m², with its EL spectrum showing emitting light maxima at λ = 445 and 472 nm. The device with PPEFE exhibited an efficiency of 0.10 cd/A and a maximum brightness of about 270 cd/m², with its EL spectrum showing an emitting light maximum at λ = 473 nm. Hole mobility (μ_h) and electron mobility (μ_e) of the polymers were determined by the time‐of‐flight method. Both polymers showed faster μ_h values. PPEBE revealed a μ_h of 2.0 × 10^?4 cm²/V·s at an electric field of 1.9 × 10⁵ V/cm and a μ_e of 7.0 × 10^?5 cm²/V·s at an electric field of 1.9 × 10⁵ V/cm. In contrast, the mobilities of the both carriers were slower for PPEFE, and its μ_h (8.0 × 10^?6 cm²/V·s at an electric field of 1.7 × 10⁶ V/cm) was 120 times its μ_e (6.5 × 10^?8 cm²/V·s at an electric field of 8.6 × 10⁵ V/cm). The much better balance in the carriers' mobilities appeared to be the major reason for the better device performance of PPEBE than PPEFE. Their highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) levels were also a little different from each other. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 299–306, 2006     

Highly fluorinated poly(ether‐imide)s derived from 2,2′‐bis(3,4,5‐trifluorophenyl)‐4,4′‐diaminodiphenyl ether and aromatic dianhydrides

A new diamine, 2,2′‐bis(3,4,5‐trifluorophenyl)‐4,4′‐diaminodiphenyl ether (FPAPE) was synthesized through the Suzuki coupling reaction of 2,2′‐diiodo‐4,4′‐dinitrodiphenyl ether with 3,4,5‐trifluorophenylboronic acid to produce 2,2′‐bis(3,4,5‐trifluorophenyl)‐4,4′‐dinitrodiphenyl ether (FPNPE), followed by palladium‐catalyzed hydrazine reduction of FPNPE. FPAPE was then utilized to prepare a novel class of highly fluorinated all‐aromatic poly(ether‐imide)s. The chemical structure of the resulting polymers is well confirmed by infrared and nuclear magnetic resonance spectroscopic methods. Limiting viscosity numbers of the polymer solutions at 25 °C were measured through the extrapolation of the concentrations used to zero. M_n and M_w of these polymers were about 10 000 and 25 000 g mol^?1, respectively. The polymers showed a good film‐forming ability, and some characteristics of their thin films including color and flexibility were investigated qualitatively. An excellent solubility in polar organic solvents was observed. X‐ray diffraction measurements showed that the fluoro‐containing polymers have a nearly amorphous nature. The resulting polymers had T_g values higher than 340 °C and were thermally stable, with 10% weight loss temperatures being recorded above 550 °C. Based on the results obtained, FPAPE can be considered as a promising design to prepare the related high performance polymeric materials. Copyright © 2011 Society of Chemical Industry     

Synthesis and properties of poly(arylene ether)s based on 3‐pentadecyl 4,4'‐biphenol

A new biphenol, 3‐pentadecyl 4,4′‐biphenol, was synthesized starting from 3‐pentadecylphenol and was polycondensed with 4,4′‐difluorobenzophenone, 1,3‐bis(4‐fluorobenzoyl)benzene and bis(4‐fluorophenyl)sulfone to obtain poly(arylene ether)s with biphenylene linkages in the backbone and pendent pentadecyl chains. Inherent viscosities and number‐average molecular weights (M_n) of the poly(arylene ether)s were in the range 0.50 ? 0.81 dL g^?1 and 2.2 × 10⁴ ? 8.3 × 10⁴, respectively. Detailed NMR spectroscopic studies of the poly(arylene ether)s indicated the presence of constitutional isomerism which existed because of the non‐symmetrical structure of 3‐pentadecyl 4,4′‐biphenol. The poly(arylene ether)s readily dissolved in common organic solvents such as dichloromethane, chloroform and tetrahydrofuran and could be cast into tough, transparent and flexible films from their chloroform solutions. The poly(arylene ether)s exhibited T_g values in the range 35–60 °C which are lower than that of reference poly(arylene ether)s without pentadecyl chains. The 10% decomposition temperatures (T₁₀) of the poly(arylene ether)s were in the range 410–455 °C indicating their good thermal stability. A gas permeation study of poly(ether sulfone) containing pendent pentadecyl chains revealed a moderate increase in permeability for helium, hydrogen and oxygen. However, there was a large increase in permeability for carbon dioxide which could be attributed to the internal plasticization effect of pendent pentadecyl chains. © 2016 Society of Chemical Industry     

Organosoluble polyimides derived from asymmetric 2‐substituted‐and 2,2′,6‐trisubstituted‐4,4′‐oxydianilines

We report a new method for the preparation of asymmetric diamines using 4,4′‐oxydianiline (4,4′‐ODA) as the starting material. By controlling the equivalents of bromination agent, N‐bromosuccinimide, we were able to attach bromide and phenyl substituents at the 2‐ or 2,2′,6‐positions of 4,4′‐ODA. Thus, four new asymmetric aromatic diamines, 2‐bromo‐4,4′‐oxydianiline (6), 2,2′,6‐tribromo‐4,4′‐oxydianiline (7), 2‐phenyl‐4,4′‐oxydianiline (8) and 2,2′,6‐triphenyl‐4,4′‐oxydianiline (9), were synthesized by this method. Their structural asymmetry was confirmed using ¹H NMR spectroscopy. Asymmetric polyimides (PI10–PI13) were prepared from these diamines and three different dianhydrides (pyromellitic dianhydride (PMDA), 3,3′,4,4′‐biphenyltetracarboxylic dianhydride and 2,2‐bis(3,4‐dicarboxyphenyl)hexafluoropropane dianhydride) in refluxing m‐cresol. The formed polyimides, except PI10a derived from 6 and PMDA, were all soluble in m‐cresol without premature precipitation during polymerization. These polyimides with inherent viscosity of 0.41–0.96 dL g^?1, measured at a concentration of 0.5 g dL^?1 in N‐methyl‐2‐pyrrolidone at 30 °C, can form tough and flexible films. Because of the structural asymmetry, they also exhibited enhanced solubility in organic solvents. Especially, polyimides PI11a and PI13a derived from 7 and 9 with rigid PMDA were soluble in various organic solvents at room temperature. The structural asymmetry of the prepared polyimides was also evidenced from ¹H NMR spectroscopy. In the ¹H NMR spectrum of PI11a, the protons of pyromellitic moiety appeared in an area ratio of 1:2:1 at three different chemical shifts, which were assigned to head‐to‐head, head‐to‐tail and tail‐to‐tail configurations, respectively. These polyimides also exhibited good thermal stability. Their glass transition temperatures ranged from 297 to 344 °C measured using thermal mechanical analysis. © 2013 Society of Chemical Industry     

Synthesis and characterization of the two novel liquid crystalline epoxy resins based on bisphenol‐s mesogen

Two novel liquid crystalline epoxy resins (LCER) based on bisphenol‐S mesogen, 4,4′‐Bis‐(2,3‐epoxypropyloxy)‐sulfonyl bis(1,4‐phenylene) (p‐BEPSBP) and sulfonyl bis(4,1‐phenylene) bis[4‐(2,3‐epoxypropyloxy)benzoate] (p‐SBPEPB), were synthesized. Their liquid crystalline behavior and structure were characterized by Fourier transmittance infrared ray (FTIR), differential scanning calorimetry (DSC), ¹HNMR, polarized optical microscopy (POM) and X‐ray diffraction (XRD). The results show that p‐BEPSBP is a kind of thermotropic liquid crystal and has a smectic mesophase with a melting point (T_m) at 165°C; the p‐SBPEPB is a kind of nematic mesophase with the temperature range of 155–302°C from the T_m to the clearing point T_i. The curing behaviors and texture of the liquid crystalline epoxy resins with 4,4′‐diaminodiphenyl ether (DDE) were also studied by DSC and some kinetic parameters were evaluated according to the Ozawa's method. The dynamic mechanical properties of curing products were also investigated by torsional braid analysis (TBA), and the results suggest that the dynamic mechanical loss peak temperature (T_p) of p‐BEPSBP/DDE and p‐SBPEPB/DDE is 120 and 130°C, respectively. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis and characterization of conducting poly(aniline‐co‐diaminodiphenylsulfone) copolymers

Polyaniline, poly(aniline‐co‐4,4′‐diaminodiphenylsulfone), and poly(4,4′‐diaminodiphenylsulfone) were synthesized by ammonium peroxydisulfate oxidation and characterized by a number of techniques, including infrared spectroscopy, ultraviolet–visible absorption spectroscopy, ¹H‐NMR, thermogravimetric analysis, and differential scanning calorimetry. These copolymers had enhanced solubility in common organic solvents in comparison with polyaniline. The conductivities of the HCl‐doped polymers ranged from 1 S cm^?1 for polyaniline to 10^?8 S cm^?1 for poly(4,4′‐diaminodiphenylsulfone). The copolymer compositions showed that block copolymers of 4,4′‐diaminodiphenylsulfone (r₁ > 1) and aniline (r₂ < 1) formed and that the reactivity of 4,4′‐diaminodiphenylsulfone was greater than that of aniline. The results were explained by the effect of the ? SO₂? group present in the polymer structure. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2337–2347, 2003