Synthesis and characterization of poly(1-benzoylthiosemicarbazide) and poly(1,3,4-thiadiazole amine) from 2-(p-aminophenyl)-1,3,4-oxadiazoline-5-thione via ring-opening process

A novel thermally stable and semiconducting polyheterocycle, poly(1,3,4-thiadiazole amine), was synthesized from 2-(p-aminophenyl)-1,3,4-oxadiazoline-5-thione via ring-opening. The polymer is a new class of ordered alternating copoly(aniline) containing 1,3,4-thiadiazole heterocyclic units. An investigation of the reaction of 2-phenyl-1,3,4-oxadiazoline-5-thione with aniline was conducted as a model reaction for the polymerization, and poly(phosphoric acid) (PPA) and phosphorus pentoxide/methanesulfonic acid (PPMA) were found to be favorable both as condensing agent and solvent for the formation of 2-anilino-5-phenyl-1,3,4-thiadiazole as a model compound. The polymerization was carried out both by two-step procedure that included ring-opening self-polyaddition giving poly(1-benzoylthiosemicarbazide), followed by cyclodehydration to poly(1,3,4-thiadiazole amine), and by a one-step procedure including cyclodehydration in situ. The poly(1-benzoylthiosemicarbazide) which was formed in the first step in m-cresol had reduced viscosities up to 0,42 dL·g^?1, and it was converted to poly(1,3,4-thiadiazole amine) by treating in PPA or PPMA. Poly(1,3,4-thiadiazole amine) having reduced viscosities up to 0,25 dL·g^?1 was also synthesized by the direct one-step polymerization in PPA or PPMA. The polymer is highly thermally stable and exhibited no weight loss up to 350°C under nitrogen. Its electric conductivity was less than 10^?10 S·cm^?1 at ambient temperature, but markedly increased to 2,9·10^?7 S·cm^?1 upon doping with iodine.     

Synthesis and properties of aromatic polypyrazoles from bis(β-substituted vinyl ketones) and aromatic dihydrazines

Polycyclocondensations of aromatic dihydrazines 2a and 2b with 1,6-diethoxy-1,5-hexadiene-3,4-dione ( 1a ) in m-cresol and those with bis(3-chloroacryloyl)benzenes 1b and 1c in 1-methyl-2-pyrrolidone (NMP) lead to aromatic polypyrazoles 3a – f having inherent viscosities up to 0,35 dl.g^?1. The polymers are soluble in polar aprotic solvents like NMP and some acidic media including m-cresol. Thermogravimetry shows a loss of 10 wt.-% at ≈ 500°C both in air and nitrogen.     

Synthesis and characterization of a rubber incorporated polyamideimide

A new flexible and crosslinkable copolyimide was prepared by low temperature polycondensation between bis [4-(4-chloroformylphthalimido)phenyl] ether ( 1 ), bis(4-aminophenyl) ether and liquid α,ω-bis[2-(4-piperazinyl)ethylaminocarbonyl]poly(butadiene-co-acrylonitrile) in DMAc solution. The polymer is soluble in DMF, DMAc, NMP, m-cresol, DMSO and concentrated sulfuric acid. On heating with or without dicumyl peroxide the polymer was crosslinked.     

Synthesis and characterization of new diphenylfluorene-based aromatic polyamides derived from 9,9-bis[4-(4-carboxy-phenoxy)phenyl]fluorene

A new bis(ether-carboxylic acid), 9,9-bis[4-(4-carboxyphenoxy)phenyl]fluorene ( 3 ), was synthesized from the nucleophilic fluorodisplacement of p-fluorobenzonitrile with the dipotassium bisphenolate of 9,9-bis(4-hydroxyphenyl)fluorene, followed by alkaline hydrolysis of the intermediate bis(ether nitrile). A novel series of aromatic polyamides containing ether and bulky fluorenylidene groups were prepared by the direct polycondensation of the diacid 3 with various aromatic diamines in N-methyl-2-pyrrolidone (NMP) solution containing dissolved CaCl₂ using triphenyl phosphite and pyridine as condensing agents. The obtained polyamides have inherent viscosities in the range of 0.50–1.75 dL/g. All the polymers are readily soluble in a variety of organic solvents, such as NMP, N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), and m-cresol, and afford transparent, flexible, and tough films by solvent casting. These polyamides have glass transition temperatures ranging from 200 to 303°C and show no significant weight loss up to 450°C, with 10% weight loss being recorded above 511°C in nitrogen or air.     

Synthesis and thermal properties of poly(enaminonitriles) containing flexible ether units

Poly(enaminonitriles) containing flexible alkyl ether units were prepared by reacting p-bis(1-chloro-2,2-dicyanovinyl)benzene with various α,ω-bis(4-aminophenoxy)alkanes in N-methyl-2-pyrrolidone (NMP). All the polymers are soluble in polar aprotic solvents such as N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), N,N-dimethylacetamide (DMAc) and NMP as well as in common organic solvents such as tetrahydrofuran and acetone. High molecular weight polymers possessing inherent viscosities in the range of 0.82–1.20 dL/g were obtained and tough films were cast from a DMF solution. They showed a large exotherm around 340°C attributable to the chemical changes of the dicyanovinyl group. Thermogravimetric analyses exhibited a good thermal stability with a 10% weight loss around 450°C and 73–88% residual weight at 500°C under nitrogen.     

New poly(amide-imide) syntheses, 3. Preparation and properties of cardo poly(amide-imide)s derived from 9,9-bis(4-aminophenyl)fluorene,trimellitic anhydride,and various aromatic diamines

An imide-ring-containing dicarboxylic acid, N,N′-(9-fluorenylidenedi-1,4-phenylene)diphthal-imide-4-carboxylic acid ( 1 ), was prepared by condensation of trimellitic anhydride and 9,9-bis(4-aminophenyl)fluorene. A series of new aromatic cardo poly(amide-imide)s having inherent viscosities of 0,59-1,13 dL/g were prepared by the direct polycondensation of this diimide-diacid with various aromatic diamines using triphenyl phosphite and pyridine as condensing agents in 1-methyl-2-pyrrolidone (NMP) in the presence of calcium chloride. The polymers are amorphous and readily soluble in highly polar solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, NMP, and m-cresol. Transparent and tough films can be easily cast from the polymer solutions. The glass transition temperatures of these poly(amide-imide)s are above 320°C. Thermal analyses indicated that these polymers are fairly stable, and the 10% weight loss temperatures were recorded in the range of 532–622°C in nitrogen atmosphere.     

Cometabolic degradation of o-cresol and 2,6-dimethylphenol by Penicillium frequentans Bi 7/2

o-Cresol induced glucose-grown resting mycelia of Penicillium frequentans Bi 7/2 (ATCC-number: 96048) immediately oxidized o-cresol and other phenols. After precultivation on glucose and phenol degradation started after a lag-phase of 24 hours. Metabolites of o-cresol metabolism were methylhydro-quinone, methyl-p-benzoquinone, 2-methyl-5-hydroxyhydroquinone and 2-methyl-5-hydroxy-p-benzo-quinone. The initial reaction is probably catalyzed by a NADPH dependent hydroxylase which is specific for o-cresol. The metabolism of 2,6-dimethylphenol (2,6-xylenol) occurred via 2,6-dimethylhydroqui-none, 2,6-dimethyl p-benzoquinone, 2,6-dimethyl-3-hydroxyhydroquinone, 2,6-dimethyl-3-hydroxy-p-benzoquinone and 3-methyl-2-hydroxybenzoic acid.     

Synthesis and properties of aromatic polyamides derived from 2,7-bis(4-aminophenoxy)napthalene and aromatic dicarboxylic acids

2,7-Bis(4-aminophenoxy)naphthalene, a new polymer-forming diamine, was synthesized in two steps by the preparation of 2,7-bis(4-nitrophenoxy)naphthalene from 2,7-dihydroxynaphthalene and p-chloronitrobenzene and subsequent reduction with a 10% Pd-C catalys and hydrazine hydrate. Aromatic polyamides and copolyamides having an inherent viscosity in the range of 0,76–1,16 dL/g were prepared by the direct polycondensation of the diamine with various aromatic dicarboxylic acids or with mixed dicarboxylic acids in 1-methyl-2-pyrrolidone (NMP) using triphenyl phosphite and pyridine as condensing agents. Most of the polymers were soluble in aprotic solvents such as NMP and N,N-dimethylacetamide (DMAc), and afforded transparent, flexible and tough films upon casting from DMAc solutions. Glass transition temperatures of the polymers were in the range of 246–327°C, and 10% weight loss temperatures were above 501°C in nitrogen and 476°C in air, respectively.     

Poly(amide-imide)s prepared from 4,4′-[1,4(or 1,3)- phenylenebis(isopropylidene-1,4-phenyleneoxy)]dianiline,trimellitic anhydride,and various aromatic diamines

Two imide ring-bearing dicarboxylic acids, N,N′-[1,4(or 1,3)-phenylenebis(isopropylidene-1,4-phenyleneoxy-1,4-phenylene)]diphthalimide-4-carboxylic acid (p-4 and m-4), were prepared via condensation of 4,4′-[1,4(or 1,3)-phenylenebis(isopropylidene-1,4-phenyleneoxy)]dianiline (p-3 and m-3) with trimellitic anhydride. Two series of novel poly(amideimide)s were synthesized by the direct polycondensation of the diimide-diacids p-4 and m-4, respectively, with various aromatic diamines using triphenyl phosphite and pyridine as condensing agents. The inherent viscosities of the resultant poly(amide-imide)s were in the range of 0,43–1,68 dL/g, and most of these polymers were amorphous, as revealed by wideangle X-ray diffractograms. Almost all the poly(amide-imide)s were readily soluble in polar aprotic solvents such as N-methyl-2-pyrrolidone (NMP), N,N-dimethylacetamide (DMAc), and N,N-dimethylformamide (DMF), and could be solution-cast into transparent, flexible, and tough films. These polymers had glass transition temperatures in the range of 200-267°C and showed no significant decomposition below 450°C, with 10% weight loss being recorded above 485°C in nitrogen or air.     

Synthesis and properties of polyamides based on a spirobichroman bis(ether-carboxylic acid)

High molar-mass aromatic polyamides were obtained from 7,7'-bis(4-carboxyphenoxy)-4,4,4′,4′-tetramethyl-2,2′-spirobichroman, a novel dicarboxylic acid monomer, by direct polycondensation reaction in N-methyl-2-pyrrolidone (NMP) with various aromatic diamines, using triphenyl phosphite and pyridine as condensing agents. Polyamides having inherent viscosities of 0,73–1,08 dL/g were obtained in quantitative yield. All the polyamides, even that derived from benzidine, are completely amorphous and readily soluble in a variety of organic solvents such as NMP, N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), and m-cresol. Their solutions can be cast into transparent, flexible and tough films. All the polyamides show distinct glass transitions in the range of 182–235°C on their differential scanning calorimetry (DSC) traces. The 10% weight loss temperatures in nitrogen and air are above 416 and 422°C, respectively.     

Synthesis and properties of aromatic polyamides based on 4,4′-[1,4(1,3 or 1,2)-phenylenedioxy]dibenzoic acid

Three isomeric bis(ether carboxylic acid)s, 4,4′-[1,2(1,3 or 1,4)-phenylenedioxy]dibenzoic acid (o-, m-, or p- 3 ) were prepared by nucleophilic substitution reaction of the potassium phenolate of catechol, resorcinol, and hydroquinone, respectively, with p-fluorobenzonitrile, giving the corresponding bis(ether nitrile)s, followed by alkaline hydrolysis. There series of isomeric polyamides were synthesized by direct polycondensation of the bis(ether carboxylic acid)s with various aromatic diamines in N-methyl-2-pyrrolidone (NMP) solution containing dissolved metal salts such as CaCl₂ or LiCl using triphenyl phosphite and pyridine as condensing agents. The resultant polyamides had inherent viscosities of 0,52–1,63 dL/g. Most of the polymers were soluble in polar aprotic solvents such as N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), NMP, and dimethyl sulfoxide. The catechol-based polyamides revealed markedly higher solubility than those based on hydroquinone or resorcinol. Transparent, flexible and tough films could be cast from the DMAc or NMP solutions of most of the polyamides. All the casting films were characterized by tensile tests. The glass transition temperatures (T_g's) of most polyamides could be determined with the help of differential scanning calorimetry (DSC) traces, which were recorded in the range of 183–232°C. In general, the polyamides based on catechol had T_g's comparable with the ones of the hydroquinone-based polyamides and higher T_g's than the corresponding resorcinol-based ones. Thermogravimetric analysis data of these polymers indicated that all the polyamides were stable up to 400°C in both air and nitrogen atmospheres.     

Synthesis of ABC-triblock copolymers for light emitting diodes

In this paper we report on the synthesis and characterization of ABC-triblock copolymers poly(N-vinylcarbazole)-block-poly(4-(1-pyrenyl)butyl vinyl ether)-block-poly(2-[4-(2-phenyl-1,3,4-oxdiazolyl)phenyloxy]ethyl vinyl ether) 15 . The ABC-triblock copolymers were synthesized by sequential living cationic polymerization of N-vinylcarbazole 11 , 4-(1-pyrenyl)butyl vinyl ether 10 and 2-chloroethyl vinyl ether 3 . In a second step, the reactive pendant chloro groups of the poly(2-chloroethyl vinyl ether) segment of the block copolymers were substituted with 2-(4-hydroxyphenyl)-5-phenyl-1,3,4-oxadiazole 6 to form fully functionalized ABC'-triblock copolymers. The molecular weight of the block copolymers varied from M _n = 4800 to 14000. The thermal behavior is discussed with respect to the block copolymer composition and compared with corresponding polymer blends. LED characteristics of a single layer device for one of the block copolymers are presented as an example.     

Photoconductivity of 3,5-dinitrobenzoate of poly[1-phenyl-1-penten-3-yn-5-ol] (DN-PPPYO) blended with poly[4-(p-N,N-diphenylaminophenyl)-1-phenyl-1-buten-3-yne] (PPAPBEY) as a hole transporting polymer

The 3,5-dinitrobenzoate of poly[1-phenyl-1-penten-3-yn-5-ol] (DN-PPPYO) blended with a charge transporting polymer, poly[4-(p-N,N-diphenylaminophenyl)-1-phenyl-1-buten-3-yne] (PPAPBEY), and polystyrene shows high photoconductivity due to the high concentration of the triphenylamine (TPA) moiety and the fully conjugated backbone as verified by xerographic measurements.     

Novel Semi‐Fluorinated Poly(ether imide)s Derived From 4‐(p‐Aminophenoxy)‐3‐trifluoromethyl‐4′‐aminobiphenyl

An unsymmetrical diamine monomer 4‐(p‐aminophenoxy)‐3‐trifluoromethyl‐4′‐aminobiphenyl has been synthesized successfully. This monomer leads to the synthesis of different novel poly(ether imide)s when reacted with different dianhydrides like pyromellatic dianhydride (PMDA), benzophenone tetracarboxylic acid dianhydride (BTDA), 2,2‐bis(3,4‐dicarboxyphenyl) hexafluoropropane (6FDA), and oxy diphthalic anhydride (ODA). The poly(ether imide) prepared from this monomer on reaction with 6FDA is soluble in several organic solvents such as N‐methylpyrolidinone (NMP), dimethylformamide (DMF), N,N‐dimethylacetamide (DMAc), tetrahydrofuran (THF), and CHCl₃. The poly(ether imide)s prepared from BTDA and ODA are soluble in NMP, DMF, and DMAc but not in THF or CHCl₃, whereas the polymer prepared from PMDA is soluble only in NMP. The water uptake value for these poly(ether imide) films is very low (0.2–0.5%), and exhibited low dielectric constants (2.81 at 1 MHz). The polymers exhibited high thermal stability up to 532 °C in air for 5% weight loss, and high glass transition temperatures up to 288 °C. The polymer exhibited high tensile strength up to 135 MPa, modulus 3.2 GPa, and elongation at break up to 25%, depending on the exact polymer structure.

The structure of the poly(ether imide) synthesised from 4‐(p‐aminophenoxy)‐3‐trifluoromethyl‐4′‐aminobiphenyl and 2,2‐bis(3,4‐dicarboxyphenyl) hexafluoropropane. This polymer was soluble in many organic solvents.     

Synthesis and characterization of new cardo polyamide-imides containing ether and tricyclo[5.2.1.02, 6]decane groups

A new cardo diimide-dicarboxylic acid, 8,8-bis[4-(4-trimellitimidophenoxy)phenyl]tricyclo-[5.2.1.0^{2, 6}]decane (BTPTD), containing an ether linkage and a tricyclo[5.2.1.0^{2, 6}]decane group was synthesized by condensation reaction of 8,8-bis[4-(4-aminophenoxy)phenyl]tricyclo[5.2.1.0^{2, 6}]decane with trimellitic anhydride. A series of new cardo polyamide-imides were prepared by direct polycondensation of BTPTD with various aromatic diamines in N-methyl-2-pyrrolidinone (NMP) using triphenyl phosphite and pyridine as condensing agents. The polymers were produced with high yield and moderate to high inherent viscosities, i. e., of 0.73–1.36 dL·g^–1. Nearly all polymers are readily soluble in polar aprotic solvents such as NMP, N,N-dimethylacetamide (DMAc), N,N-dimethylformamide, dimethyl sulfoxide as well as less polar solvents such as pyridine, γ-butyrolactone, and tetrahydrofuran. These polymers were solution-cast from DMAc solution into transparent, flexible, and tough films except for polymers 4 a and 4 b . Wide-angle X-ray measurement revealed that all polymers were amorphous. These polyamide-imides have glass transition temperatures between 250–290°C and 5% weight loss temperatures in the range of 445 to 491 and 462 to 490°C in nitrogen and air atmosphere, respectively. The polymer films have a tensile strength range of 77 to 87 MPa, an elongation at break range of 3 to 9%, and a tensile modulus range of 2.2 to 2.8 GPa.     

Synthesis,characterization and properties of a hyperbranched aromatic polyamide: poly(ABZAIA)

A hyperbranched aromatic polyamide has been prepared by direct polycondensation of 5‐(4‐aminobenzoylamino)isophthalic acid (ABZAIA), using the modified Higashi's method. The resultant polymer is soluble in aprotic polar solvents such as DMF, DMAc, NMP, and DMSO. Intrinsic viscosities of poly(ABZAIA) samples, measured in sulfuric acid at 25°C, are in the range between 0.2 and 0.3 dL·g^–1. Glass transition temperature (T_g) is placed around 150°C and onset temperature of thermal decomposition at about 275°C. Full molecular weight distribution, evaluated by a SEC apparatus equipped with three different detectors, gives M_w values in the range between 55 000 and 300 000 g·mol^–1, with a polydispersity index, M_w/M_n, relatively large and generally around 3–4. Poly(ABZAIA), synthesized in suitable experimental conditions, shows rather low values of Mark‐Houwink a constant. Together with [η] data, these a values are consistent with a hyperbranched, close‐to‐globular shape of our polymer. Highly concentrated polymer solutions (> 40 wt.‐%) in NMP show shear birefringence under polarized light. The specific surface area of the powdered material, calculated by nitrogen adsorption/desorption isotherm, is ca. 40 m²·g^–1.     

p-Cresol inhibits IL-12 production by murine macrophages stimulated with bacterial immunostimulant

p-Cresol, an end product of aromatic amino acids, is produced from food proteins by intestinal bacteria, and is detectable in blood and feces. Especially, blood and fecal levels of p-cresol are high in chronic renal failure (CRF) patients. Although it has been suggested that p-cresol is toxic in the body, the effect of p-cresol on immune responses has not yet been clarified. In this study, we investigated the effect of p-cresol on IL-12 production of macrophages stimulated with Lactobacillus casei strain Shirota (LcS) in vitro. Pre-incubation with p-cresol inhibited IL-12 p40 production of LcS-stimulated J774.1 cells, a murine macrophage-like cell line, in a dose-dependent manner. IL-12 p40 and p70 production of LcS-stimulated murine peritoneal macrophages was also inhibited by p-cresol. The inhibitory effect was not dependent on the cytotoxicity of p-cresol. These results indicate that blood and fecal p-cresol may have adverse effects on the host defense system in CRF patients.     

Self polycondensation of oxalyl dihydrazide

In order to obtain a linear poly(1,3,4-oxadiazole-2,5-diyl) the self-polycondensation of oxalyl dihydrazide has been investigated. Polymers with molecular weight up to 6000 were prepared by solution polycondensation in N-methylpyrrolidone containing lithiumchloride. These polymers are thermally stable up to 300°C. They were characterized by IR spectra, thermal analysis and solubilities.     

Synthesis of poly[bis(benzimidazobenzisoquinolinones)] in various reaction media

The influence of various reaction media, monomer concentration, temperature and reaction time on reduced viscosities η_red of semiladder poly[bis(benzimidazobenzisoquinolinones)] was studied using the 4,4′-[isopropylidenebis(1,4-phenyleneoxy)]di-1,8-naphthalenedicarboxylic anhydride/3,3′-diaminobenzidine condensation reaction as a model. m-Cresol/P₂O₅, m-cresol/benzoic acid, m-cresol/polyphosphoric acid, m-cresol/di-m-cresyl phosphate, phenol/P₂O₅, and p-chlorophenol/P₂O₅ were used as reaction media and it was found that the m-cresol/P₂O₅ system was the best one. The use of the m-cresol/P₂O₅ medium for the synthesis of poly[bis-(benzimidazobenzisoquinolinones)] based on other dinaphthalene derived dianhydrides confirmed the universal applicability of this system. All the polymers obtained in the m-hcresol/P₂O₅ medium showed high reduced viscosities and were film- and fibre-generating.     

Synthesis and viscosity behavior of poly(γ-p-biphenylmethyl-L-glutamate) in benzene/dichloroacetic acid mixtures,a comparison with poly(γ-benzyl-L-glutamate)

The synthesis of poly(γ-p-biphenylmethyl-L-glutamate), PBPLG, (poly{L-imino-1-[2-(4-biphenylylmethoxycarbonyl)ethyl]-2-oxoethylene}), ( 1d ) is described. The viscosity behavior of this polymer in benzene/dichloroacetic acid mixtures (c=0,2.10^—3—1,4.10^—3 g/cm³) at 25°CC is investigated. The results are compared with measurements on poly(γ-benzyl-L-glutamate), PBLG, (poly[L-imino-1-(2-benzyloxycarbonylethyl)-2-oxoethylene]), ( 1c ) under the same conditions. A transition from a rigid hydrogen bonded helix to a random solvated coil occurs in two stages for both: PBPLG (first stage 0—55%, second stage 55—100% dichloroacetic acid) and PBLG (first stage 0—70%, second stage 70—100% dichloroacetic acid). Therefore, the introduction of a p-phenyl substituent in PBLG leads to a less stable helix in benzene/dichloroacetic acid mixtures. The stability and viscosity behavior of PBLG in benzene/dichloroacetic acid mixtures (c=0,2.10^—3—1,4.10^—3g/cm³) is quite similar to the behavior of PBLG in m-cresol/dichloroacetic acid mixtures (c=1,0.10^—3—4,0.10^—3 g/cm³).