Synthesis and characterization of N‐methyl‐2‐nitrodiphenylamine‐4‐diazonium salt and its diazoresin

A new substituted diphenylamine diazonium salt, N‐methyl‐2‐nitrodiphenylamine‐4‐diazonium salt (MNDDS) and its diazoresin (MNDDS‐resin) were synthesized and their thermostability as well as photosensitivity were investigated. The results show that MNDDS and resin exhibit much higher thermostability than that of the parent compound, diphenylamine‐4‐diazonium salt (DDS) and resin (DDS resin) in solid state or in coating but the photosensitivities of them are confirmed to be in same level. The excellent thermostability of MNDDS and its diazoresin is very important because the storage life of a negative presensitized plate is mainly dependent on it. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 189–193, 1999     

Conductivity and Flash–photolysis Studies of the Light Stability of Nitrodiphenylamine Dyes

Previous work on nitrodiphenylamine dyes has drawn attention to the relation between light fastness, structure and spectra. In this work the connection between structure and spectra is further investigated using conductivity measurements. The nature of the excited species formed on exposure to near–ultraviolet radiation is examined by flash–photolysis techniques and by investigation of the changes in conductivity caused by the exposure.     

The Photofading of 1 –Arylazo–2–naphthols in Solution.

1–(Substituted phenylazo)–2–naphthols with a nitro group positioned para– or ortho– to the azo group, show anomalous photofading behaviour in methanol, i. e., their fastness to light is very much lower than that of similar compounds. On the other hand, although 1 –(o–nitrophenylazo)–2–naphthol (II) in alcoholic solvents faded to give similar products via photooxidative and/or photoreductive reactions, little photoreduction of the nitro group was detected, and the rate of photofading of II was lower than that of la. The contribution of intramolecular interaction, such as intramolecular bifurcated hydrogen bonding, involving the o–nitro group, azo group and o–hydroxy group of 1–(o–nitrophenylazo)–2–naphthol, are also discussed. Photochemical reaction of 1–(p–nitrophenylazo)–2–naphthol (la) in methanol, ethanol or 2–propanol produces not only oxidative but also reductive products, while photochemical reaction of la in acetone gives only oxidative products. From these results and earlier observations, it is suggested that the anomalous photofading of la is a substrate–specific phenomenon, and may be caused by photo–reduction of the nitro and azo groups to amino groups by the substrate, instead of the normal photo–oxidation of the hydrazone tautomer by singlet oxygen.     

4–Hydroxy–3–arylamino–l, 8–naphthalimides and 3–(and 4–) hydroxy–2–(and 5–) arylamino–7H–bcnzimidazo–(2, l–a)benz(d,e)isoquinolin–7–ones. Red dyes for synthetic–polymer fibres

4–Hydroxy–1, 8–naphthalimides and the isomer mixtures of'3–and 4–hydroxy–7 H–benzimidazo–(2, l–a)–benz(d, e)–isoquinolin–7–ones were coupled with diazotised arylamines to yield orange–red to bluish–red dyes having good coloration properties and excellent fastness to light on polyester fibres. Structure–property relationships in the dyes are discussed with respect to the nature of the substituents in the imide, imidazole and arylazo moieties.     

Substituent Effects on the Colour,Dyeing and Fastness Properties of Trisubstituted 4–N–β–Hydroxyethyl–N–β–Cyanoethylaminoazobenzenes

School of Chemistry and Chemical Technology University of Bradford Bradford West Yorkshire BD7 1DP The synthesis of a series of 2′, 4′, 6′-trisubstituted derivatives of 4–N–β–hydroxyethyl–4– N–β–cyanoeth ylaminoazobenzene is reported, and the effect of the nature of the substituents on the colour, dyeing and fastness properties of these dyes is described. The dyes coloured synthetic–polymer fibres well, with the exception of those containing a methylsulphonyl group, which gave weaker dyeings on polyester. Dyes substituted by 2′-nitro groups tended to have poor light fastness, and reasons for the variations in the light fastness of monoazo dyes of this type are discussed.     

Nanostructured PZT synthesized from metal–polyvinyl alcohol gel: Studies on metal–polymer interaction

PbZr_0.53Ti_0.47O₃ (PZT) nanoparticles of size distribution ～1–6 nm were synthesized by single‐step autoignition of metal–polyvinyl alcohol (PVA) gel. The physical and chemical bonding between the metals ions and PVA in gel was analyzed from the results of the characterization by FTIR, SEM, and XRD techniques. The appearance of a doublet band between 3500 and 3200 cm^?1 and the shifting of stretching frequency of O? H band in the FTIR spectra of gel indicated strong electrostatic interaction between the metal ions and the polar OH groups of the polymer. The electrostatic interaction decreased the extent of hydrogen bonding drastically due to engagement of polar OH groups in complex formation with the metal ions. Microstructural study of the dried gel by SEM coupled with its FTIR analyses indicated crosslinking in the metal–polymer gel. The loss of crystallinity of PVA in gel detected by XRD also indicated the drastic degradation of hydrogen bonding in PVA due to the formation of coordination complex with the metal ions. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

New Intermediates and Dyes for Synthetic–polymer Fibres 4–(4–Methoxyanilino)–3–nitro–l, 8–naphthalimides

The synthesis of a series of 4–(4–methoxyanilinoj–3–nitro–1, 8–naphthalimides by condensation of amines with 4–(4–methoxyanilino)–3–nitronaphthalene–l, 8–dicarboxylic anhydride, and also by condensation of 4–halogeno–3–nitro–1, 8–naphthalimides with 4–methoxyaniline is described. They dye synthetic–polymer fibres, particularly polyesters, deep orange of excellent fastness properties. In presence of strong bases, e. g. 3–aminopropan–l–ol, the 4–arylamino group is replaced, giving a series of yellow dyes. A method is described for preparing the dyes without isolation of intermediate stages.     

Eliminating Voids at Al2O3–Cu Interface During Direct Bonding

Direct bonding copper technique employs a eutectic liquid from Cu–O system to bond copper to alumina. Many semispherical voids are found at the Al₂O₃–Cu interface after bonding. Both the amount and the size of voids increase with the increase of oxygen content in copper. The void formation is resulted from the reduction of Cu₂O precipitates during bonding. Based on this observation, an approach to prevent the formation of voids is proposed. The approach introduces a sacrificial coating onto Al₂O₃ substrate before bonding. The coating consumes the oxygen from the reduction, and the amount of voids is then reduced significantly.     

Polymer–solute interactions in solid–liquid two‐phase partitioning bioreactors

BACKGROUND: Biphasic systems with immiscible solvents have been studied for in situ product removal, and have shown improvements in bioreactor performance, however, problems associated with solvent biocompatibility, bioavailability and operation have been identified. One alternative is the solid–liquid system in which polymer beads are used, absorbing and removing target compounds from the aqueous phase while maintaining equilibrium conditions. This work aims to identify polymer properties that may be important in polymer selection for selected biotransformation molecules including 2‐phenylethanol, cis‐1,3‐indandiol, iso‐butanol, succinic acid and 3‐hydroxybutyrolactone. RESULTS: Relatively hydrophobic compounds (e.g. 2‐phenylethanol) tend to be absorbed by polymers better than hydrophilic ones (e.g. iso‐butanol) based on partition coefficient tests; values as high as 80 were obtained for the former and < 3 for the latter. Owing to the presence of polar functional groups on these compounds, polar polymers such as Hytrel® performed better than non‐polar ones such as Kraton®. Crystallinity and intermolecular hydrogen‐bonding were also found to be important polymer properties. CONCLUSION: Polymers showed excellent results in absorbing hydrophobic compounds such as aromatic alcohols, and positive results in absorbing hydrophilic compounds but to a lesser extent. Grafting hydrophilic functional groups onto polymers may be a promising approach for extending polymer uptake capabilities and is currently being investigated. Copyright © 2009 Society of Chemical Industry     

Benzo[k,l], xanthene–3, 4–dicarboximides and benzimidazoxanthenoisoquinolinones – yellow and orange dyes for synthetic–polymer fibres

Condensation of 4–chloro–l, 8–naphthalic anhydride with 2–nitrophenol afforded 4–(2–nitrophenoxy)–l, 8–naphthalic anhydride, which on reduction followed by Pschorr intramolecular cyclisation gave benzo[k, l]xanthene–3, 4–dicarboxylic acid anhydride. The identity of the product was confirmed by its alternative synthesis from 5–amino–4–phenoxy–l, 8–naphthalic anhydride. Benzo[k, l]xanthene–3, 4–dicarbox–ylic acid anhydride condensed with alkylamines or arylamines and with o–phenylenediamines to yield the corresponding imides and imidazole derivatives, which coloured polyester in fluorescent greenish–yellow to orange hues, respectively, of good fastness to light and sublimation. The colour of the dyes is discussed with respect to analogous ring–closed sulphur– containing heterocycles.     

Organosoluble and light‐colored fluorinated polyimides based on 2,2‐bis[4‐(4‐amino‐2‐trifluoromethylphenoxy)phenyl]propane and aromatic dianhydrides

A novel fluorinated diamine monomer, 2,2‐bis[4‐(4‐amino‐2‐trifluoromethylphenoxy)phenyl]propane (2), was prepared through the nucleophilic substitution reaction of 2‐chloro‐5‐nitrobenzotrifluoride with 2,2‐bis(4‐hydroxyphenyl)propane in the presence of potassium carbonate, followed by catalytic reduction with hydrazine and Pd/C. Polyimides were synthesized from diamine 2 and various aromatic dianhydrides 3a–f via thermal imidization. These polymers had inherent viscosities ranging from 0.73 to 1.29 dL/g. Polyimides 5a–f were soluble in amide polar solvents and even in less polar solvents. These films had tensile strengths of 87–100 MPa, elongations to break of 8–29%, and initial moduli of 1.7–2.2 GPa. The glass transition temperatures (T_g) of 5a–f were in the range of 222–271°C, and the 10% weight loss temperatures (T₁₀) of them were all above 493°C. Compared with polyimides 6 series based on 2,2‐bis[4‐(4‐aminophenoxy)phenyl]propane (BAPP) and polyimides 7 based on 2,2‐Bis[4‐(4‐aminophenoxy)phenyl]hexafluoropropane (6FBAPP), the 5 series showed better solubility and lower color intensity, dielectric constant, and lower moisture absorption. Their films had cutoff wavelengths between 363 and 404 nm, b* values ranging from 8 to 62, dielectric constants of 2.68–3.16 (1 MHz), and moisture absorptions in the range of 0.04–0.35 wt %. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 922–935, 2005     

Thermodynamic Analysis on the Codeposition of SiC–Si3N4 Composite Ceramics by Chemical Vapor Deposition using SiCl4–NH3–CH4–H2–Ar Mixture Gases

A thermodynamic calculation on the chemical vapor deposition of the SiCl₄–NH₃–CH₄–H₂–Ar system was performed using the FactSage thermochemical software databases. Predominant condensed phases at equilibrium were SiC, Si₃N₄, graphite, and Si. The equilibrium conditions for the deposition of condensed phases in this system were determined as a function of the deposition temperature, dilution ratio (δ), and reactant ratios of CH₄/SiCl₄ and NH₃/SiCl₄. The CVD phase diagrams were used to understand the reactions occurring during the formation of Si–C–N from the gas species and determine the area of SiC–Si₃N₄. The concentration of condensed‐phase products was used to determine the deposition conditions of CVD SiC–Si₃N₄. The present work was helpful for further experimental investigation on CVD Si–C–N.     

Preparation and properties of acrylonitrile–butadiene rubber–graphene nanocomposites

The graphene oxide (GO) was prepared by sonication‐induced exfoliation from graphite oxide, which was produced by oxidation from graphite flakes with a modified Hummer's method. The GO was then treated by hydrazine to obtain reduced graphene oxide (rGO). On the basis of the characterization results, the GO was successfully reduced to rGO. Acrylonitrile–butadiene rubber (NBR)–GO and NBR–rGO composites were prepared via a solution‐mixing method, and their various physical properties were investigated. The NBR–rGO nanocomposite demonstrated a higher curing efficiency and a change in torque compared to the gum and NBR–GO compounds. This agreed well with the crosslinking density measured by swelling. The results manifested in the high hardness (Shore A) and high tensile modulus of the NBR–rGO compounds. For instance, the tensile modulus at a 0.1‐phr rGO loading greatly increased above 83, 114, and 116% at strain levels of 50, 100, and 200%, respectively, compared to the 0.1‐phr GO loaded sample. The observed enhancement was highly attributed to a homogeneous dispersion of rGO within the NBR matrix; this was confirmed by scanning electron microscopy and transmission electron microscopy analysis. However, in view of the high ultimate tensile strength, the NBR–GO compounds exhibited an advantage; this was presumably due to strong hydrogen bonding or polar–polar interactions between the NBR and GO sheets. This interfacial interaction between GO and NBR was supported by the marginal increase in the glass‐transition temperatures of the NBR compounds containing fillers. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42457.     

Evaluating p97 Inhibitor Analogues for Potency against p97–p37 and p97–Npl4–Ufd1 Complexes

We previously found that the p97 cofactor, p47, significantly decreased the potency of some ATP‐competitive p97 inhibitors such as ML240 [2‐(2‐amino‐1H‐benzo[d]imidazol‐1‐yl)‐N‐benzyl‐8‐methoxyquinazolin‐4‐amine] and ML241 [2‐(2H‐benzo[b][1,4]oxazin‐4(3H)‐yl)‐N‐benzyl‐5,6,7,8 tetrahydroquinazolin‐4‐amine]. In this study, we aimed to evaluate inhibitor potencies against two additional p97 cofactor complexes, p97–p37 and p97–Npl4–Ufd1. We focused on these two cofactor complexes, because the protein sequence of p37 is 50 % identical to that of p47, and the Npl4–Ufd1 heterodimer (NU) is the most‐studied p97 cofactor complex. We screened 200 p97 inhibitor analogues for their ability to inhibit the ATPase activity of p97 alone and of p97–p37 and p97–NU complexes. In contrast to the effect of p47, p37 and NU did not significantly change the potencies of most of the compounds. These results highlight differences among p97 cofactors in influencing p97 conformation and effects of inhibitors on p97 complexes, as compared to p97 alone. Continued efforts are needed to advance the development of complex‐specific p97 inhibitors.     

Phosphorus‐containing poly(ester‐imide)–polydimethylsiloxane copolymers

New phosphorus‐containing poly(ester‐imide)‐polydimethylsiloxane copolymers were prepared by solution polycondensation of 1,4‐[2‐(6‐oxido‐6H‐dibenz < c,e > < 1, 2 > oxaphosphorin‐6‐yl)]naphthalene‐bis(trimellitate) dianhydride with a mixture of an aromatic diamine (1,3‐bis(4‐aminophenoxy)benzene) and α,ω‐bis(3‐aminopropyl)oligodimethylsiloxane of controlled molecular weight, in various ratios. Poly(amic acid) intermediates were converted quantitatively to the corresponding polyimide structures using a solution imidization procedure. The polymers are easily soluble in polar organic solvents, such as N‐methyl‐2‐pyrrolidone and N,N‐dimethylformamide, as well as in less polar solvents such as tetrahydrofuran. They show good thermal stability, the decomposition temperature being above 370 °C. The glass transition temperatures are in the range 165–216 °C. Solutions of the polymers in N‐methyl‐2‐pyrrolidone exhibit photoluminescence in the blue region. Copyright © 2010 Society of Chemical Industry     

Kristallinflüssige trans-4-(ω-Cyanalkyl)cyclohexylester und 4-(ω-Cyanalkyl)phenylester

Liquid Crystalline trans-4-(ω-Cyanalkyl)cyclohexylester and 4-(ω-Cyanalkyl)phenylesters The synthesis of the title esters 1 and 2a–e (n = 0 – 3) and their mesomorphic properties are described. When the alkyl-spacer n between the polar CN-group and the cyclohexane ring of cyanalkyl-cyclohexylesters 1 is increased the difference of the clearing points between the phenylesters 2 and the cyclohexylesters 1 decreases to nearly zero. The reason of higher clearing temperatures of 2 is a dynamic conformational effect of ring inversion of cyclohexane in the ester 1 with two polar substituents at the ring.     

Synthetic Procedures Yielding Targeted Nitro and Nitroso Derivatives of the Propellant Stabilisers Diphenylamine,N‐Methyl‐4‐nitroaniline,and N,N′‐Diethyl‐N,N′‐diphenylurea

Synthetic methodologies have been developed which yield a variety of diphenylamine (DPA) and 1,3‐diethyl‐l,3‐diphenylurea (ethylcentralite or EC) propellant stabiliser degradation derivatives in high yield. The N‐alkyl nitroanilines (N‐methyl‐2,4,6‐trinitroaniline; N‐methyl‐2,4‐dinitroaniline; N‐ethyl‐2,4,6‐trinitroaniline; N‐ethyl‐2,4‐dinitroaniline; N‐ethyl‐4‐nitroaniline; N‐ethyl‐2‐nitroaniline) have been obtained either by reaction of the parent aniline with the required alkyl halide under mild conditions or via Ullmann type chemistry. A robust and high yielding approach for the synthesis of di, tri and tetranitrodiphenylamines (2,2′,4,4′‐tetranitrodiphenylamine; 2,4,4′‐trinitrodiphenylamine; 2,2′,4‐trinitrodiphenylamine; 2,4,6‐trinitrodiphenyl‐amine; 2,4‐dinitrodiphenylamine) is reported which involves passing the nitroanilines and chloronitrobenzenes down a base activated alumina column. The N‐nitroso‐N‐alkyl compounds (N‐nitroso‐N‐ethyl‐4‐nitroaniline; N‐nitroso‐N‐ethyl‐2‐nitroaniline; N‐nitroso‐N‐Methyl‐4‐nitroaniline; N‐ethyl‐N‐nitrosoaniline; N‐nitroso‐2‐nitrodiphenylamine) have been synthesised using nitrosyl acetate in acetic acid as the N‐nitrosating agent.     

Competitive hydrogen bonding mechanisms underlying phase behavior of triple poly(N‐vinyl pyrrolidone)–poly(ethylene glycol)–poly(methacrylic acid‐co‐ethylacrylate) blends

Differential scanning calorimetry (DSC) of triple blends of high molecular weight poly(N‐vinyl pyrrolidone) (PVP) with oligomeric poly(ethylene glycol) (PEG) of molecular weight 400 g/mol and copolymer of methacrylic acid with ethylacrylate (PMAA‐co‐EA) demonstrates partial miscibility of polymer components, which is due to formation of interpolymer hydrogen bonds (reversible crosslinking). Because both PVP and PMAA‐co‐EA are amorphous polymers and PEG exhibits crystalline phase, the DSC examination is informative on the phase state of PEG in the triple blends and reveals a strong competition between PEG and PMAA‐co‐EA for interaction with PVP. The hydrogen bonding in the triple PVP–PEG–PMAA‐co‐EA blends has been established with FTIR Spectroscopy. To evaluate the relative strengths of hydrogen bonded complexes in PVP–PEG–PMAA‐co‐EA blends, quantum‐chemical calculations were performed. According to this analysis, the energy of H‐bonding has been found to diminish in the order: PVP–PMAA‐co‐EA–PEG(OH) > PVP–(OH)PEG(OH)–PVP > PVP–H₂O > PVP–PEG(OH) > PMAA‐co‐EA–PEG(? O? ) > PVP–PMAA‐co‐EA > PMAA‐co‐EA–PEG(OH). Thus, most stable complexes are the triple PVP–PMAA‐co‐EA–PEG(OH) complex and the complex wherein comparatively short PEG chains form simultaneously two hydrogen bonds to PVP carbonyl groups through both terminal OH‐groups, acting as H‐bonding crosslinks between longer PVP backbones. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Effect of ZrO2 Addition on Densification and Mechanical Properties of MgAl2O4–CaAl4O7–CaAl12O19 Composite

Although the platelet structure of calcium hexaluminate (CaAl₁₂O₁₉, or CA₆) grains can strengthen and toughen the Al₂O₃–MgO–CaO system materials designed in the high‐alumina region, it also results in poor densification and subsequent accelerated slag penetration for refractory application. Considering this aspect, MgAl₂O₄–CaAl₄O₇–CaAl₁₂O₁₉ composite was fabricated by solid‐state reaction sintering in this work, and the effect of ZrO₂ addition on densification and mechanical properties was investigated. The results showed that the CA₆ grains presented a more equiaxed morphology by addition of ZrO₂, contributing to form highly dense microstructures after heating at 1600°C without evident grain coarsening. The compressive strength and flexural strength were greatly enhanced mainly due to the significant decrease in porosity and pore sizes. Besides, the increased content of ZrO₂ plays an active role in toughening this composite attributed to the dense microstructure and strong bonding with higher strength, as well as considerable t‐ZrO₂ transformability.     

Synthesis and characterization of new aromatic poly(amide–imide)s based on 4‐aryl‐2,6‐bis(4‐trimellitimidophenyl) pyridines

New diimide–dicarboxylic acids, ie 4‐phenyl‐2,6‐bis(4‐trimellitimidophenyl)pyridine and 4‐p‐biphenyl‐2,6‐bis‐(4‐trimellitimidophenyl)pyridine, were synthesized by the condensation reaction of 4‐phenyl‐2,6‐bis(4‐aminophenyl)pyridine and 4‐p‐biphenyl‐2,6‐bis(4‐aminophenyl)pyridine with trimellitic anhydride in glacial acetic acid or dimethylformamide. The monomers were fully characterized by FT‐IR and NMR spectroscopies, and elemental analyses. A series of novel poly(amide–imide)s with inherent viscosities of 0.68–0.87 dl g^?1 was prepared from the two diimide–diacids with various aromatic diamines by direct polycondensation. The poly(amide–imide)s were characterized by FT‐IR and NMR spectroscopies. The λ_max data for the resulting poly(amide–imide)s were in the range of 260–292 nm. These polymers exhibited good solubilities in polar aprotic solvents. The 10 % weight loss temperatures are above 485 °C under a nitrogen atmosphere. Copyright © 2004 Society of Chemical Industry