Polymers of diphenylamine-2-carboxylic acid: Synthesis, structure, and properties

Polymers of diphenylamine-2-carboxylic acid are prepared by chemical oxidative polymerization in an aqueous solution of ammonium hydroxide. In accordance with the IR data, during the polymerization of diphenylamine-2-carboxylic acid in a solution of ammonium hydroxide, polymer-chain growth occurs via C-C joining into 2 and 4 positions of phenyl rings with respect to nitrogen. The distinctive feature of the polymer is the absence of quinodiimine units in its structure, even if the oxidizer is in excess. The resulting polymers are amorphous, electroactive, and thermally stable.     

Thermal stability of polydiphenylamine synthesized through oxidative polymerization of diphenylamine

The thermal stability of polydiphenylamine synthesized through the oxidative polymerization of diphenylamine has been studied. It has been established that the main processes of thermal and thermooxidative degradation of polydiphenylamine begin at 600–650 and 450°C, respectively. It has been shown that, in the course of thermal oxidation of the doped polydiphenylamine, the elimination of a dopant takes place first. With a further increase in temperature, the behavior of this material becomes similar to that of the neutral polymer.     

Polymerization of aromation amines with ferric chloride to produce thermally stable polymers

Simple aromatic amines have been polymerized by use of ferric chloride as a combined Friedel-Crafts catalyst and oxidant to yield polymers which are both thermally and oxidatively stable. Under certain reaction conditions a polydiphenylamine was prepared which was stable in air up to 465°C as shown by thermogravimetric analysis. This polymer has a softening point of ca. 80–100°C and is soluble in some organic solvents. Such a polydiphenylamine and other polymers with similar properties are regarded as useful for conversion to thermally stable Phillips-type resins by crosslinking with conventional difunctional agents.     

Research in the field of heterocyclic chemistry. XXXVIII. Mechanism of the acridone synthesis based on diphenylamine-2-carboxylic acids

The mechanism of synthesis of acridones based on treatment of diphenylamine-2-carboxylic acid with phosphorus oxychloride is considered. It is established that triphenylamine-2-carboxylic acid and the anilide of diphenylamine-2-carboxylic acid, when treated with phosphorus oxychloride, give high yield of 10-phenylacridone and 9-anilinoacridone respectively. The hitherto undescribed N-(o-chlorobenzoyl)diphenylamine-2-carboxyanilide is obtained by reacting phenylanthranilanilide with o-chlorobenzoyl chloride, or by heating o-chlorobenzanilide with copper powder in nitrobenzene.For Part XXXVII see [1].     

Thermoreversible gelation of poly(ethylene oxide) biodegradable polyester block copolymers

The gel to sol transition of aqueous solutions of di‐ and triblock copolymers consisting of poly(ethylene oxide) and biodegradable polyesters was studied as a function of temperature. The molecular weight and the chemical composition of the biodegradable blocks, (poly(l ‐lactic acid), poly(dl ‐lactic acid), poly(dl ‐lactic acid‐co‐caprolactone), and poly(dl ‐lactic acid‐co‐glycolic acid)) were varied to investigate the effects of chain packing and relative hydrophobicity on the gel to sol transition. The block copolymers studied formed micelles at lower concentrations in water, while the concentrated solutions experienced a gel to sol transition as the temperature increased. Further increase in temperature resulted in the precipitation of polymers. With increasing molecular weight and chain packing tendency of hydrophobic biodegradable block, the gel to sol transition occurred at lower concentrations and the transition temperature ranged from 0°C to over 90°C in a relatively narrow concentration range. The results obtained in this study confirm the relationship between gelation properties and polymer structure, as well as provide more information for these polymers in drug delivery applications. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 751–760, 1999     

Poly(N-isopropylacrylamide). II. Effect of polymer concentration,temperature, and surfactant on the viscosity of aqueous solutions

The effects of polymer concentration, temperature, and surfactant on the rheological properties of poly(N-isopropylacrylamide), poly NIPAM, were studied. Below 28°C the viscosity decreased with increasing temperature according to the Arrhenius expression. However, at 29°C the viscosity increased to a maximum value at 32°C, the lower critical solution temperature (LCST) for aqueous polyNIPAM. Higher temperatures gave a much lower viscosity. This unusual rheological behavior was explained by the phase behavior of the polymer. Sodium dodecyl sulfate (SDS) binding to polyNIPAM increased the cloud point temperature (CPT) and attenuated the unusual rheological behavior of polyNIPAM in water. © 1993 John Wiley & Sons, Inc.     

Novel positive‐working and aqueous‐base‐developable photosensitive poly(imide benzoxazole) precursor

A novel positive‐working and aqueous‐base‐developable photosensitive poly(imide benzoxazole) precursor based on a poly(amic acid hydroxyamide) bearing phenolic hydroxyl groups and carboxylic acid groups, a diazonaphthoquinone (DNQ) photosensitive compound, and a solvent was developed. Poly(amic acid hydroxyamide) was prepared through the polymerization of 2,2‐bis(3‐amino‐4‐hydroxyphenyl)hexafluoropropane, trimellitic anhydride chloride, and 4,4′‐oxydibenzoyl chloride. Subsequently, the thermal cyclization of the poly(amic acid hydroxyamide) precursor at 350 °C produced the corresponding poly(imide benzoxazole). The inherent viscosity of the precursor polymer was 0.17 dL/g. The cyclized poly(imide benzoxazole) showed a high glass‐transition temperature of 372 °C and 5% weight loss temperatures of 535 °C in nitrogen and 509 °C in air. The structures of the precursor polymer and the fully cyclized polymer were characterized with Fourier transform infrared and ¹H NMR. The photosensitive polyimide precursor containing 25 wt % DNQ photoactive compound showed a sensitivity of 256 mJ/cm² and a contrast of 1.14 in a 3‐μm film with a 0.6 wt % tetramethylammonium hydroxide developer. A pattern with a resolution of 5 μm was obtained from this composition. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5990–5998, 2004     

ESR spectra of poly(methacrylic acid) and poly(methyl methacrylate): Reinterpretation of the 9-line spectrum

The temperature dependence of the ESR spectra of poly(methacrylic acid) and poly-(methyl methacrylate) γ-irradiated at room temperature was studied between ?196°C and +25°C. The conventional 9-line spectrum was observed throughout this range with no significant spectral change, in contrast to the propagating radical ··· CH₂? °C(CH₃)COOR found in methacrylic acid monomer or barium methacrylate dihydrate irradiated at ?196°C. In addition, the irradiation of methacrylic acid monomer with a low dose at 0°C gave the same 13-line spectrum as that of the propagating radical obtained by the irradiation at ?196°C, while prolonged irradiation at 0°C gave the same conventional 9-line spectrum as that of poly(methacrylic acid) or poly(methyl methacrylate). The conventional 9-line spectrum has a much weaker 4-line component than that of the propagating radical. The difference comes from the surrounding matrix, and the conventional 9-line spectrum is well interpreted by introducing the concept of the distribution of the conformational angle in the irregular polymer matrix. From simulation of the ESR spectrum, it was found that the intensity of the 4-line component is very sensitive to the distribution, and that the observed 9-line spectrum is well reproduced assuming a Gaussian distribution (half-height width of 5–6°) around the most probable conformation which is nearly the same as that of the propagating radical, where the conformational angles of the two C? H_β bonds to the half-filled p-orbital are 55° and 65°.     

Isolation and cationic ring-opening polymerization of 2,3,5,6-tetrahydroimidazo[2,1-b][1,3]oxazole to produce a thermally stable polyurea

A bicyclic pseudourea, 2,3,5,6-tetrahydroimidazo[2,1-b][1,3]oxazole ( 1 ), was isolated for the first time, and its cationic and spontaneous polymerizations were examined. Both polymerizations gave poly(1,3-imidazolidin-2-one-1,3-diylethylene) ( 2 ) in high yields. The polymer is a crystalline solid with glass transition and melting temperature of 51°C and 286°C, respectively. Thermogravimetry showed that it is stable up to 450°C under nitrogen.     

Synthesis and characterization of poly[4-(4-hydroxyphenoxy) benzoic acid]

Poly[4-(4-hydroxyphenoxy) benzoic acid] was prepared by the bulk polycondensation of 4-(4-acetoxyphenoxy) benzoic acid. Polycondensation was conducted at 350°C for 3 h under a reduced pressure of 0.1 mmHg and gave a polymer with X?n of 255. The polymer was characterized by elemental analysis, IR spectroscopy, differential scanning calorimetry, and wide-angle X-ray measurement. The crystal/nematic and nematic/isotropic phase transition temperatures of polymer, which depend on the molecular weight, were observed at about 300°C and 410°C, respectively. The polymers with low molecular weights showed nematic textures above 300°C. This nematic/isotropic phase transition temperature is lower than that of poly (4-hydroxybenzoic acid). This thermal behavior of polymer comes from ether units, which increase the flexibility (the rotation or torsion of skeletal bonds) of the polymer chain. © 1994 John Wiley & Sons, Inc.     

Thermal decyanation,a new organic reaction. II

When heated in solution at about 160°C, pyridine quaternary salts of bromomalonamides lose 1 mole of cyanic or isocyanic acid almost quantitatively in a manner quite analogous to the decarboxylation of an acid. By DTA and DSC, the crystalline salts are stable up to their melting points (>220°C) at which temperatures concurrent fusion and decyanation processes occur (endotherm); these are immediately followed by an exotherm related to the trimerization of cyanic acid. TGA measurements on the solid salts do not clearly define the loss of 1 mole of cyanic acid because in the solid state, thermal decyanation is accompanied to some extent by other pyrolytic reactions. Preparative methods for quaternizing poly(4-vinylpyridine) with bromomalonamide are described and two polymeric quaternary salts (33 and 100% substituted) were prepared and analyzed. These polyelectrolytes are water soluble and upon the addition of base the yellow polymeric nitrogen ylids are generated. Infrared spectra on the polymeric quaternary salts and visible spectra on the polymeric ylids are included. The ylid chromophore has an ε = 1800 at λ_max = 415 nm. The dilute solution viscosity behavior of these polymers in H₂O and in 0.05N KBr is typical of polyelectrolytes. Both polymers in dilute solution show a maximum in η_sp versus pH plots. In water, the viscosity of these polymers decreases with time, and it is proven that this results from a conformational change which accompanies amide hydrolysis rather than polymer backbone degradation. Glass transitions are not detectable by DTA but both polymers show well-defined trimerization exotherms for cyanic acid starting at 170–175°C. Thus, decyanation of the solid polymeric quaternary salts is more analogous to decyanation of the crystalline quaternarys in solution than as solids. TGA measurements on the polymers show weight losses which are of the correct order of magnitude and in the correct temperature range for monodecyanation. Some data are presented which suggest that perhaps a second mole of cyanic acid is lost at about 250°C. Quaternization of poly(4-vinylpyridine) with bromomalonamide reduces its gross decomposition temperature from 385°C to about 285–317°C. It is demonstrated how thermal decyanation can be used for the in situ generation of cyanic acid for the modification of organic compounds. The preparation of a partial urethane of poly(vinyl alcohol) using this method is described. We have also shown that aliphatic quaternary salts can be prepared and that they too undergo the decyanation reaction.     

Deuterium Isotope Effect on the Phase Separation of Zipper‐Type Hydrogen‐Bonding Inter‐Polymer Complexes in Solution

We have investigated the deuterium isotope effect on phase separation in aqueous zipper‐type hydrogen‐bonding polymer solutions. The phase separation temperature of poly(acrylic acid)‐poly(acrylamide) in heavy water is about 16°C higher than that in water. This large isotope effect in the aqueous zipper‐type macromolecular system arises from the polymer‐polymer interaction due to cooperative hydrogen bonds in the polymer‐polymer complex.     

Methylmercury(II) complexes with 2-mercaptopyridinecarboxylic acids

The stability constants of the complexes [MeHgL]^?(H₂L = 2-mercaptopyridine-3-carboxylic acid, 2-mercaptopyridine-4-carboxylic acid, 2-mercaptopyridine-5-carboxylic acid and 2-mercaptopyridine-6-carboxylic acid) have been obtained by differential pulse polarography. The values of log β₁ are in the range 14.14–14.96 at 20°C and ionic strength 0.1 mol dm^?3. The complexes MeHgHL have been isolated and characterized by chemical analysis and mass and IR spectrometry.     

Thermal analysis of poly(p-xylylene) and poly(α,α,α′,α′-tetrafluoro-p-xylylene)

The TG(DTG) and DTA of poly(p-xylylene) and poly(α,α,α′,α′-tetrafluoro-p-xylylene) are reported. The degradation was performed from ambient temperature to 900°C in both air and nitrogen. Both polymer degrade faster in air than under nitrogen but the fluorinated polymer eventually decomposed at higher temperature in air than in nitrogen atmosphere. The activation energies of the degradation processes is given.     

Synthesis and characterization of aromatic poly(ether ketone)s containing cyclotriphosphazene units

Bis(4-oxybenzoic acid) tetrakis(phenoxy) cyclotriphosphazene (IUPAC name: 4-[4-(carboxyphenoxy)-2,4,6,6-tetraphenoxy-1,3,5,2λ⁵,4λ⁵,6λ⁵-triazatriphosphinin-2-yl]oxy-benzoic acid) was synthesized and direct polycondensed with diphenylether or 1,4-diphenoxybenzene in Eaton's reagent at the temperature range of 80–120°C for 3 hours to give aromatic poly(ether ketone)s. Polycondensations at 120°C gave polymer of high molecular weight. Incorporation of cyclotriphosphazene groups in the aromatic poly(ether ketone) backbone greatly enhanced the solubility of these polymers in common organic polar solvents. Thermal stabilities by TGA for two polymer samples of polymer series ranged from 390 to 354°C in nitrogen at 10% weight loss and glass transition temperatures (T_g) ranged from 81.4 to 89.6°C by DSC. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1227–1232, 1998     

γ-Ray-induced polymerization of α-haloacrylic acids

The γ-ray induced polymerizations of α-chloroacrylic acid, mp 66°C, and α-bromo-acrylic acid, mp 72°C, were investigated in the temperature range from 35°C to 85°C. An analysis of polymerization kinetics was made, and results were similar to those reported in the literature for other vinyl monomers. On heating of the polymer obtained, elimination of hydrogen halide takes place, and intramolecular lactone formation is observed. The rate of lactone formation of poly(α-chloroacrylic acid) obtained in the solid-state polymerization was found to be higher than that in the liquid state, because a highly isotactic configuration of polymers, tends to be formed in the solid-state polymerization, and elimination of hydrogen chloride is facilitated with an isotactic 5₂ helix structure.     

Higher aliphatic aldehyde polymers. VI. Poly(n-nonaldehyde)

Crystalline poly(n-nonaldehyde) (PNA) was prepared by anionic polymerization of n-nonaldehyde (NA) in methylcyclohexane (MCH) with lithium tertiary butoxide (LTB) as the initiator. Normal low-temperature conditions did not give polymer reprodusibly; however, when the polymerization was carried out with a gradual temperature decrease to ?60°C holding at this temperature followed by completion at ?78°C, a moderate yield of PNA was obtained. The polymer was acetate capped and characterized. Infrared and PMR spectroscopy, as well as degradation of the polymer in the presence of 2,4-dinitrophenylhydrazine to the hydrazone, conclusively proved the chemical structure of the polymer. VPO measurements and measurement of the inherent viscosity showed the polymer to be of moderate molecular weight. PNA is highly crystalline and shows two transition regions, one corresponding to the melting of the main chain at temperatures above 120°C and one region between 50 and 80°C, which is related to the crystallization of the aliphatic side chains. PNA, although inherently brittle, can be extruded through an orifice at a temperature near the side-chain melting temperature to give an extrudate whose x-ray patterns show the characteristics of a fiber diagram. It is suggested that the crystal structure of the PNA is similar to that of poly(n-heptaldehyde) but with a larger a spacing, which is expected from a longer aliphatic side chain.     

Direct condensation polymerization of lactic acid

In order to synthesize the higher molecular weight poly(lactic acids) by direct condensation polymerization of lactic acid, dipentaerythritol was used as a chain branching agent. Poly(lactic acids) of high molecular weight, 67000(Mn), was obtained by using antimony trioxide catalyst with good color. This poly(lactic acids) showed Tg of 54.8 °C, Tm of 147 °C and cold crystallization temperature of 115 °C. The polymer could be melt processed into transparent films. Tensile modulus of 311 Kg/ mm², tensile strain of 21% and tensile strength of 12.41 Kg/ mm² were obtained for film collected at 400%/min and drawn 4 times.     

Synthesis and characterization of poly[3,5′-(3-pyridyl methyl)-2,6,-diaminotoluene] and its condensation product,poly[4-(3-pyridyl),8-methyl,2,3-6,7-quinolino]

2,6-Diaminotoluene was reacted with 3-pyridinecarboxaldehyde in acidic medium and the intermediate polymer was further condensed in polyphosphoric acid at high temperature (335°C) to obtain a soluble heterocyclic ladder polymer, poly[4-(3-pyridyl),8-methyl,2,3–6,7-quinolino] (PPMQ). The molecular weight of the intermediate polymer depended on the reaction temperature and the rate of reactant addition. The NMR spectra of the intermediate polymer indicated that a linear polymer with resonable molecular weight was formed. Element analysis and IR spectra confirmed the structure of the final polymer.     

Determination of interaction parameter χ1, for poly(vinyl alcohol) and water in gels crosslinked from solutions

The Flory interaction parameter χ₁ of poly(vinyl alcohol)-water systems has been estimated as a function of temperature and volume fraction of PVA, the polymer having been crosslinked from solutions of the same in water. Values are reported for temperatures between 0°C and 90°C and polymer volume fractions between 0.03 and 0.12.