4-Nitro­phenyl 2-chloro­benzoate

The aromatic rings in the title compound, C13H8ClNO4, enclose a dihedral angle of 39.53 (3)°. The nitro group is almost coplanar with the ring to which it is attached [dihedral angle = 4.31 (1)°]. In the crystal, molecules are connected by C-H...O hydrogen bonds into chains running along [001]. Key indicators: single-crystal X-ray study; T = 173 K; mean σ(C–C) = 0.002 A°; R factor = 0.044; wR factor = 0.105; data-to-parameter ratio = 18.9

N-[4-(4-Nitrophenoxy)phenyl]-propionamide

The title compound, C15H14N2O4, is an important intermediate for the synthesis of thermotropic liquid crystals. The dihedral angle between the two aromatic rings is 84.29 (4)°. An N-H...O hydrogen bond connects the molecules into chains running along the b axis. In addition, the crystal packing is stabilized by weak C-H...O hydrogen bonds. Key indicators: single-crystal X-ray study; T = 173 K; mean σ(C–C) = 0.002 Å; R factor = 0.036; wR factor = 0.096; data-to-parameter ratio = 14.3

4-(4-Nitrophenoxy)biphenyl

The two phenyl rings of the biphenyl unit of the title compound, C18H13NO3, are almost coplanar [dihedral angle 6.70 (9)°]. The nitrophenyl ring, on the other hand, is significantly twisted out of the plane of the these two rings, making dihedral angles of 68.83 (4)° with the middle ring and 62.86 (4)° with the end ring. The nitro group is twisted by 12.1 (2)° out of the plane of the phenyl ring to which it is attached. Key indicators: single-crystal X-ray study; T = 173 K; mean σ(C–C) = 0.002 A° ; R factor = 0.040; wR factor = 0.118; data-to-parameter ratio = 12.8

Thermal, rheological, mechanical and morphological behavior of HDPE/chitosan blend

A peroxide-Initiated melt compounding technique was used to graft and crosslink the high density polyethylene/chitosan blend using vinyl triethoxysilane Different percentage of chitosan (up to maximum of 35%) was added in HDPE/chitosan blends The physical and functional properties of the crosslinked HDPE/chitosan blends were investigated and compared with its non-crosslinked congener IR spectrum of crosslinked blend confirmed the presence of Si-O-Si and Si-O-C absorption peaks at 1020 cm(-1) and 1105 cm(-1) Increased gel content was obtained with increasing chitosan loading whereas percentage crystallinity was decreased Rheological study of crosslinked blends showed linear viscoelastic behavior with high complex viscosity and dynamic shear storage modulus Tensile strength of crosslinked HDPE was 9 3 MPa and it was increased by threefold to 27 4 MPa in crosslinked HDPE/chitosan blends containing 35% chitosan contents Similarly lower deformation was observed in crosslinked blends under static load Scanning electron microscopy revealed good adhesion between matrix-filler interphase (C) 2010 Elsevier Ltd All rights reserve

N-(4-Chlorophenyl)-4-nitrobenzamide

The title compound, C13H9ClN2O3, is almost planar, showing a dihedral angle of 4.63 (6)° between the aromatic ring planes. The nitro group also lies in the plane, the C—C—N—O torsion angle being 6.7 (2)°. There is an intamolecular C—H...O hydrogen bond. The crystal structure features N—H...O(nitro) hydrogen bonds that link the molecules into zigzag chains extending along [010]

Synthesis and characterization of novel coatable polyimide-silica nanocomposites

We report synthesis of a novel diamine 1,2-bis(4-(Hydrazonomethyl)phenoxy) ethane (bis- HPE) and a derived novel polyimide. The diamine was reacted with PMDA and ODA to synthesize copolyimide. Unmodified and modified silica particles were dispersed in the polyimide to prepare polyimide-silica hybrids: (a) unmodified (PSH-UM), and (b) modified (PSH-M). The PSH-UM were prepared by generating silica particles in situ in PI. In PSH-M, structural group identical to PI, 2,6- bis(3-(triethoxysilyl)propyl)pyrrolo[3,4-f]isoindole-1,3,5,7(2H,6H)- tetraone was introduced into silica nano-particles. The structural similarity enhanced compatibility between organic-inorganic components by like-like chemical interactions as both contain flexible alkyl groups. PSH-M have shown improved surface smoothness, hydrophobicity and thermal stability. Such properties are mandatory for stable coatings. The structure of silica and PI was affirmed by FTIR, EDX, and solid-state 29Si NMR spectroscopy. Morphological and thermal properties of the prepared PI-SiO2 nano-composites were investigated by field emission scanning electron microscopy, atomic force microscopy, contact angle measurement and thermogravimetric analysis. © 2013 Springer Science+Business Media Dordrecht.FALS

Triethylammonium 4-(3,5-dinitrobenzamido)-N-(3,5-dinitrobenzoyl)benzenesulfonamidate

The molecular structure of the title salt, C6H16N+·C20H11N6O12S−, shows a planar geometry of the benzamido–phenyl–sulfonyl moiety, with a dihedral angle of 1.59 (9)° between the aromatic ring planes. The central ring and the aromatic ring of the other dinitrobenzamide group are nearly perpendicular, making a dihedral angle of 89.55 (9)°. All nitro groups lie almost in plane with the associated aromatic rings, the O—N—C—C torsion angles ranging from 9.2 (2) to 24.3 (2)°. In the crystal, strong anion–anion N—H...O and anion–cation hydrogen bonds form inversion dimers stacked along the a axis. Less prominent anion–anion C—H...O interactions lead to the formation of a three-dimensional network including anion–anion dimers as well as anion–anion chains along [100?]

Preparation and characterization of novel polyimide-silica hybrids

Polyimide-silica (PI-SiO2) hybrids were prepared from a novel polyimide (PI), derived from pyromellitic dianhydride (PMDA), 1,6-bis(4-aminophenoxy)hexane (synthesized) and 4,4′-oxydianiline. SiO2 networks (5-30wt%) were generated through sol-gel process using either tetraethylorthosilicate (TEOS) or a mixture of 3-aminopropyltriethoxysilane-PMDA-based coupling oligomers (APA) and TEOS. Thin, free standing hybrid films were obtained from the respective mixtures by casting and curing processes. The hybrid films were characterized using Fourier transform infrared, 29Si nuclear magnetic resonance (NMR), field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectrometry and atomic force microscopy (AFM) techniques. 29Si NMR results provide information about formation of organically modified silicate structures that were further substantiated by FE-SEM and AFM micrographs. Contact angle measurements and thermogravimetric thermograms reveal that the addition of APA profoundly influences surface energy, interfacial tension, thermal stability and the residual char yield of modified hybrids in comparison to those obtained by mixing only TEOS. It was found that reduced particle size, efficient dispersion and improved interphase interactions were responsible for the eventual property enhancement. © 2012 John Wiley & Sons, Ltd.