Modified poly(3-hydroxybutyrate-co-3-hydroxyvalerate) using hydrogen bonding monomers

Properties of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) were significantly modified by a hydrogen bonding (H-bond) monomer-bisphenol A (BPA). BPA lowered the T-m of PHBV and widened the heat-processing window of PHBV. At the same time, a dynamic H-bond network in the blends was observed indicating that BPA acted as a physical cross-link agent. BPA enhanced the T, of PHBV and reduced the crystallization rate of PHBV. It resulted in larger crystallites in PHBV/BPA blends showed by WAXD. However, the crystallinity of PHBV was hardly reduced. SAXS results suggested that BPA molecules distributed in the inter-lamellar region of PHBV. Finally, a desired tension property was obtained, which had an elongation at break of 370% and a yield stress of 16 MPa. By comparing the tension properties of PHBV/BPA and PHBV/tert-butyl phenol blends, it was concluded that the H-bond network is essential to the improvement of ductility.

Metal printing with modified polymer bonding lithography

SOFT CONTACT LAMINATION; LIGHT-EMITTING DEVICES; LIFT-OFF; FABRICATION; TRANSISTORS; DIODES; FILMS; STAMP

Electronic structures and chemical bonding in transition metal monosilicides MSi (M=3d, 4d, 5d elements)

Bond distances, vibrational frequencies, electron affinities, ionization potentials, dissociation energies, and dipole moments of the title molecules in neutral, positively, and negatively charged ions were studied using the density functional method. Ground state was assigned for each species. The bonding patterns were analyzed and compared with both the available data and across the series. It was found that besides an ionic component, covalent bonds are formed between the metal s, d orbitals and the silicon 3p orbital. The covalent character increases from ScSi (YSi) to NiSi (PdSi) for 3d (4d) metal monosilicides, then decreases. For 5d metal monosilicides, the covalent character increases from LaSi to OsSi, then decreases. For the dissociation of cations, the dissociation channel depends on the magnitude of the ionization potential between metal and silicon. If the ionization potential of the metal is smaller than that of silicon, channel MSi+-> M++Si is favored. Otherwise, MSi+-> M+Si+ will be favored. A similar behavior was observed for anions, in which the dissociation channel depends on the magnitude of electron affinity.

Chemical bonding and electronic structure of 4d-metal monocarbides

Bond distances, vibrational frequencies, dissociation energies, electron affinities, ionization potentials and dipole moments of the title molecules in neutral and charged ions were studied by use of density functional method. Ground states for each molecule were assigned. For neutral and cationic molecules, the bond distance decreases from YC (YC+) to RhC (RhC+), then increases, while for anionic molecules, the bond distance decreases from YC- to RuC-, then increases. Opposite trend was observed for vibrational frequency. The bond ionic character decreases from ZrC to PdC for neutral molecules. The bonding patterns are discussed and compared with the available studies.

Buildup of gold nanoparticle multilayer thin films based on the covalent-bonding interaction between boronic acids and polyols

A novel method for the fabrication of gold nanoparticle multilayer films based on the covalent-bonding interaction between boronic acid and polyols, poly(vinyl alcohol) (PVA), was developed. The multilayer buildup was monitored by UV-vis absorbance, spectroscopy, which showed a linear increase of the film absorbance with the number of adsorbed Au layers and indicated the stepwise and uniform assembling process. The atomic force microscopy (AFM) image showed that a compact gold multilayer thin film was successfully assembled. The residual boronic acid group on the surface of thin film Could incorporate glycosylated-protein horseradish peroxidase (HRP), and good catalytic activity for H2O2 could be observed.

Miscibility and hydrogen-bonding interactions in blends of carbon dioxide/epoxy propane copolymer with poly (p-vinylphenol)

The miscibility and hydrogen-bonding interactions of carbon dioxide and epoxy propane copolymer to poly(propylene carbonate) (PPC)/poly(p-vinylphenol) (PVPh) blends were investigated with differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The single glass-transition temperature for each composition showed miscibility over the entire composition range. FTIR indicates the presence of strong hydrogen-bonding interassociation between the hydroxyl groups of PVPh and the oxygen functional groups of PPC as a function of composition and temperature. XPS results testify to intermolecular hydrogen-bonding interactions between the oxygen atoms of carbon-oxygen single bonds and carbon-oxygen double bonds in carbonate groups of PPC and the hydroxyl groups of PVPh by the shift of C-1s peaks and the evolution of three novel O-1s peaks in the blends, which supports the suggestion from FTIR analyses.

Bonding and Mossbauer isomer shifts in (Tl, Pb)-1223 cuprate

By using the clinical bond theory of dielectric description, the chemical bond parameters of (Tl.Pb) - 1223 was calculated. The results show that the Sr-O, Tl-O, and Ca-O types of bond have higher ionic character and the Cu-O types of bond have more covalent, character. Mossbauer isomer shifts of Fe-57 and Sn-119 doped in (Tl, Pb) -1223 were calculated by using the chemical environmental factor, h, defined by covalency and electronic polarizability. Four valence state tin and three valence iron sites were identified ill Fe-57, and Sn-119 doped (Tl, Pb) -1223 superconductor. We conclude that all of' the Fe atoms substitute the Cu at square planar Cu (H site, whereas Sn prefers to Substitute the square pyramidal Cu (2) site.

Study of the effect of hydrogen bonding on the phase behaviour of p-nitro azobenzene derivatives with hydrophilic tails

The infrared spect ra of N-n-(4-nitrophenyl)azophenyloxyalkyldiethanolamines (Cn) are examined in the range of 4000-400 cm(-1) at different temperatures and the assignment of the fundamental vibrations given. Based on (1) the localization of the broad absorption band at 3456 cm(-1), and (2) attribution of the associated OH bands centred at 1410-1390, 1100, and 650-634 cm(-1) to, respectively delta OH deformation, nu C-O stretching and gamma OH out-of-plane bending, intermolecular hydrogen bonding between OH groups in the crystalline, liquid crystalline and isotropic states is proposed. By considering the results of FTIR, WAXD and DSC measurements, the molecular arrangement of C10 in its smectic A phase as consisting of hydrogen bonding and strong interaction between dipolar groups (NO,) is proposed. This may explain the high stability and high orientational ordering property of Cn compounds in the liquid crystalline state compared with that of n-bromo-1-[4-(4-nitrophenyl)azophenyl]oxyalkanes (Bn).

SYNTHESIS AND VARIABLE-TEMPERATURE FTIR STUDY OF 5 CHIRAL LIQUID-CRYSTALS INDUCED BY INTERMOLECULAR HYDROGEN-BONDING

Five new chiral liquid crystal systems induced by intermolecular hydrogen bonding between 4-[(S)-2-chloro-3-methyl]butyroyloxy-4'-stilbazole (MBSB, proton acceptor) and 4-alkoxybenzoic acids (nBA, proton donors) were prepared. Their liquid crystalline properties were investigated by DSC and polarized optical microscopy. Chiral nematic and chiral smectic phases were observed, and the thermal stability of one complex was studied through temperature dependent infrared spectroscopy.

SYNTHESIS OF SOME CHIRAL LIQUID-CRYSTALS AND STUDY OF THE EFFECT OF INTRAMOLECULAR HYDROGEN-BONDING ON THE PHASE-BEHAVIOR

The synthesis of three new series of chiral Schiffs bases containing benzilideneaniline and 2-hydroxybenzilideneaniline moieties as mesogenic cores is presented. Differential scanning calorimetry, optical polarizing microscopy and X-ray diffraction measurements were used to study the phase transition temperatures and behaviour. The results reveal that most of these materials show chiral smectic mesomorphism.

Chemical Bonding between Heteropoly Acid and Oxygen-containing Groups on the Surface of Activated Carbon

In order to define the force of heteropoly acids on absorbed activated carbon surface, IR spectra of 12-silicotungstic acid (SiW12) and 12-tungstophosphoric acid (PW12) absorbed on activated carbon and in oxygen-containing organic compound solutions were studied. Based on the IR spectra and UV characteristics of the heteropoly acids in various chemical conditions, the chemical bonding between heteropoly acid and oxygen-containing gropus on the surface of activated carbon was suggested.

STUDY ON BONDING AND 4F ORBITAL EFFECT OF LANTHANIDE COMPOUNDS

The bonding and the 4f orbital effect of lanthanide elements at different valence state in their compounds have been studied by INDO method in this paper. The results obtained show that the bonding of lanthanide compounds is affected by many factors, such as valence state, ionic radius, ligand, coordinate number, space configuration etc. The strength of bonds composed of different ligands with lanthanide is distinctly different. The covalence of Ln-L bonds of lanthanide ions at high valence state in their compounds is larger than that at low valence state, The covalency at low coordinate number is larger than that at high coordinate number. Some lanthanide compounds with special configuration, besides sigma-bond, can form p(pi)-d(pi) dative bond with much overlap, which makes the Ln-L bond increase markedly. The effect of 4f orbitals on bonding is far less than that of 5d orbitals. The Ln 4f orbitals at 3 or 2 valence state may be considered to be essentially localized, while the contribution of 4f orbitals on bonding in 4 valent cerium compounds increases obviously, up to 1%.

ELECTRONIC-STRUCTURE AND CHEMICAL BONDING OF EUROPIUM NITRATE COMPLEX WITH AZACROWN (2, 2)

The electronic structure and bond character of europium nitrate complex with azacrown (2, 2)(1, 7, 10, 16-tetraoxa-4, 13-diazacyclooctadecane), [Eu(NO_3)_2(2, 2)] NO_3, have been studied by means of XPS and INDO method. The data of electronic binding energies and charge distribution of atoms in the complex showed that chemical shift of less electronegative nitrogen N1s binding energy was larger than that of more electronegative oxygen O1s binding energy in coordinating atoms, and that charge transfer from N...

EFFECT OF CRYSTAL-FIELD AND BONDING PROPERTIES ON SPECTRAL STRUCTURE OF EU-2+

Five Eu~(2+)-doped simple fluorides and six Eu~(2+)-doped complex fluorides are synthesized by solid reactions. The strength of the crystal-field at the sites of Eu~(2+) ion, and the degroe of covalenco of Eu—F bond in these hosts are discussed. The f-f transition emission of Eu~(2+) ion is observed in the hosts which has lower coordination number and strong crystal-field. The f-f transition emission of Eu~(2+) ion is observed for the first time in the simple fluoride AlF_3.

Roll Project Bin Packing Benchmark Problems.

This document describes two sets of Benchmark Problem Instances for the One Dimensional Bin Packing Problem. The problem instances are supplied as compressed (zipped) SQLITE database files.