EFFECT OF K-CARRAGEENAN ON MECHANICAL, THERMAL AND BIODEGRADABLE PROPERTIES OF STARCH–CARBOXYMETHYL CELLULOSE (CMC) BIOPLASTIC

Starch–carboxymethyl cellulose (CMC) bioplastics have limited mechanical properties. Carrageenan from seaweed is a potential reinforcement material for improving the mechanical properties of bioplastics. This study aimed to determine the effect of Kappa (κ)-carrageenan on the mechanical and thermal properties and biodegradability of starch–CMC bioplastics. In this study, carrageenan at concentrations of 0%, 10%, 15%, 20%, 25% and 30% was used. The melt-mixing process was conducted at 130 °C for 4 min, using a mixer and then hot-pressing (30 kgf/cm2) at 150 °C for 5 min. The results indicated that the higher κ-carrageenan concentration increased the strength of bioplastics up to 15.7 MPa. The fracture analysis via scanning electron microscopy–energy-dispersive X-ray spectroscopy indicated the distribution of sulfur (S) elements that described the dispersion of κ-carrageenan. The Fourier transform infrared spectroscopy spectra revealed that the interaction between the starch–CMC matrix and κ-carrageenan formed a tight hydrogen bond network. The lowest mass reduction observed by thermogravimetric analysis occurred in bioplastics with 25% carrageenan, decreasing by 48% compared with bioplastics without κ-carrageenan. The addition of κ-carrageenan was identified as not affecting the biodegradability of the bioplastics.

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X-ray Crystallographic Study of Alkylammonium Anthracene-9-carboxylates as a Model for Fibrous Structure of Binary Anthracene Salt Gels

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc20041292 ◽

2004 ◽

Vol 69 (6) ◽

pp. 1292-1300 ◽

Cited By ~ 1

Author(s):

Tahahiro Tani ◽

Kazuki Sada ◽

Masatsugu Ayabe ◽

Yuya Iwashita ◽

Takanori Kishida ◽

...

Keyword(s):

Alkyl Chain ◽

Columnar Structure ◽

Hydrogen Bond Network ◽

One Dimensional ◽

X Ray ◽

Crystallographic Study ◽

Alkylammonium Salts ◽

Bond Network ◽

Fibrous Assemblies ◽

Long Alkyl Chain

Crystal structure of hexylammonium anthracene-9-carboxylate was investigated. The salt was arranged by a one-dimensional hydrogen bond network to form a columnar structure in the crystalline state. This columnar structure should be the model of fibrous assemblies in the organogels of anthracene-9-carboxylate alkylammonium salts having a long alkyl chain.

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Effect of pressure on a mixed valence FeiiFeiii2complex

Acta Crystallographica Section A Foundations and Advances ◽

10.1107/s2053273314090986 ◽

2014 ◽

Vol 70 (a1) ◽

pp. C901-C901

Author(s):

Solveig Madsen ◽

Jacob Overgaard ◽

Bo Iversen

Keyword(s):

Phase Transition ◽

Hydrogen Bond ◽

Mixed Valence ◽

Hydrogen Bond Network ◽

X Ray Diffraction ◽

X Ray ◽

Effect Of Pressure ◽

Bond Network ◽

Fe Sites ◽

Cyano Groups

Intramolecular electron transfer (ET) in mixed valence (MV) oxo-centered [FeiiFeiii2O(carboxylate)6(ligand)3]·solvent complexes is highly dependent on temperature, on the nature of the ligands, and on the presence of crystal solvent molecules [1]. Whereas the effects of temperature, crystal solvent, and ligand variation on the details of the ET have been explored thoroughly, the effect of pressure is less well described [2]. The effect of pressure on the ET in MV Fe3O(cyanoacetate)6(water)3has been investigated with single crystal X-ray diffraction and Mössbauer spectroscopy. Previous multi-temperature studies have shown that at room temperature the ET between the three Fe sites is fast and the observed structure of the Fe3core is a perfectly equilateral triangle [3]. Cooling the complex below 130 K induces a phase transition as the ET slows down. Below 120 K the Fe3core is distorted due to the localization of the itinerant electron on one of the three Fe sites in the triangle (the complex is then in the valence trapped state). The valence trapping is complete within a temperature interval of just 10 K. The abruptness of the transition has been attributed to the extended hydrogen bond network involving water ligands and cyano groups, promoting intermolecular cooperative effects. The high-pressure X-ray diffraction data show that there is a 900flip of half the cyano groups at 3.5 GPa, which dramatically changes the hydrogen bond network. At a slightly higher pressure, a phase transition is found to occur. The five single crystals investigated all broke into minor fragments at the transition; however triclinic unit cells, similar to the low temperature unit cell, could be indexed from selected spots. Additional evidence that the complex is valence trapped comes from high pressure Mössbauer spectra measured above the phase transition (4 GPa). The relationship between valence trapping and the structural changes will in this work be highlighted using void space and Hirshfeld surface analysis.

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X-ray Absorption Spectroscopy Study of the Hydrogen Bond Network in the Bulk Water of Aqueous Solutions

The Journal of Physical Chemistry A ◽

10.1021/jp050413s ◽

2005 ◽

Vol 109 (27) ◽

pp. 5995-6002 ◽

Cited By ~ 118

Author(s):

Lars-Åke Näslund ◽

David C. Edwards ◽

Philippe Wernet ◽

Uwe Bergmann ◽

Hirohito Ogasawara ◽

...

Keyword(s):

Hydrogen Bond ◽

Aqueous Solutions ◽

Absorption Spectroscopy ◽

Bulk Water ◽

Hydrogen Bond Network ◽

Spectroscopy Study ◽

X Ray ◽

Bond Network ◽

X Ray Absorption

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X-ray structures of catalytic intermediates of cytochrome c oxidase provide insights into its O2 activation and unidirectional proton-pump mechanisms

Journal of Biological Chemistry ◽

10.1074/jbc.ra119.009596 ◽

2020 ◽

Vol 295 (17) ◽

pp. 5818-5833

Author(s):

Atsuhiro Shimada ◽

Yuki Etoh ◽

Rika Kitoh-Fujisawa ◽

Ai Sasaki ◽

Kyoko Shinzawa-Itoh ◽

...

Keyword(s):

Hydrogen Bond ◽

Resonance Raman Spectroscopy ◽

Transmembrane Helix ◽

Water Channel ◽

Bound State ◽

Proton Pumping ◽

Hydrogen Bond Network ◽

X Ray ◽

Catalytic Intermediates ◽

Bond Network

Cytochrome c oxidase (CcO) reduces O2 to water, coupled with a proton-pumping process. The structure of the O2-reduction site of CcO contains two reducing equivalents, Fea32+ and CuB1+, and suggests that a peroxide-bound state (Fea33+–O−–O−–CuB2+) rather than an O2-bound state (Fea32+–O2) is the initial catalytic intermediate. Unexpectedly, however, resonance Raman spectroscopy results have shown that the initial intermediate is Fea32+–O2, whereas Fea33+–O−–O−–CuB2+ is undetectable. Based on X-ray structures of static noncatalytic CcO forms and mutation analyses for bovine CcO, a proton-pumping mechanism has been proposed. It involves a proton-conducting pathway (the H-pathway) comprising a tandem hydrogen-bond network and a water channel located between the N- and P-side surfaces. However, a system for unidirectional proton-transport has not been experimentally identified. Here, an essentially identical X-ray structure for the two catalytic intermediates (P and F) of bovine CcO was determined at 1.8 Å resolution. A 1.70 Å Fe–O distance of the ferryl center could best be described as Fea34+ = O2−, not as Fea34+–OH−. The distance suggests an ∼800-cm−1 Raman stretching band. We found an interstitial water molecule that could trigger a rapid proton-coupled electron transfer from tyrosine-OH to the slowly forming Fea33+–O−–O−–CuB2+ state, preventing its detection, consistent with the unexpected Raman results. The H-pathway structures of both intermediates indicated that during proton-pumping from the hydrogen-bond network to the P-side, a transmembrane helix closes the water channel connecting the N-side with the hydrogen-bond network, facilitating unidirectional proton-pumping during the P-to-F transition.

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Temperature dependence of the hydrogen bond network in trimethylamine N-oxide and guanidine hydrochloride–water solutions

Physical Chemistry Chemical Physics ◽

10.1039/c7cp04958g ◽

2017 ◽

Vol 19 (41) ◽

pp. 28470-28475 ◽

Cited By ~ 5

Author(s):

Felix Lehmkühler ◽

Yury Forov ◽

Mirko Elbers ◽

Ingo Steinke ◽

Christoph J. Sahle ◽

...

Keyword(s):

Hydrogen Bond ◽

Temperature Dependence ◽

Compton Scattering ◽

Guanidine Hydrochloride ◽

Hydrogen Bond Network ◽

X Ray ◽

Water Solutions ◽

Scattering Study ◽

Bond Network

We present an X-ray Compton scattering study on aqueous trimethylamine N-oxide (TMAO) and guanidine hydrochloride solutions (GdnHCl) as a function of temperature.

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Snapshots of the Fluctuating Hydrogen Bond Network in Liquid Water on the Sub-Femtosecond Timescale with Vibrational Resonant Inelastic x-ray Scattering

Physical Review Letters ◽

10.1103/physrevlett.114.088302 ◽

2015 ◽

Vol 114 (8) ◽

Cited By ~ 30

Author(s):

A. Pietzsch ◽

F. Hennies ◽

P. S. Miedema ◽

B. Kennedy ◽

J. Schlappa ◽

...

Keyword(s):

Hydrogen Bond ◽

Liquid Water ◽

Hydrogen Bond Network ◽

X Ray ◽

X Ray Scattering ◽

Bond Network ◽

Ray Scattering

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Tautomerism and hydrogen bonding in guaninium phosphite and guaninium phosphate salts

Acta Crystallographica Section B Structural Science ◽

10.1107/s0108768107005332 ◽

2007 ◽

Vol 63 (3) ◽

pp. 448-458 ◽

Cited By ~ 11

Author(s):

El-Eulmi Bendeif ◽

Slimane Dahaoui ◽

Nourredine Benali-Cherif ◽

Claude Lecomte

Keyword(s):

Hydrogen Bond ◽

Hydrogen Bonding ◽

Crystal Structures ◽

Monoclinic Space Group ◽

Data Sets ◽

Hydrogen Bond Network ◽

Space Group ◽

X Ray ◽

Bond Network ◽

Phosphate Salts

The crystal structures of three similar guaninium salts, guaninium monohydrogenphosphite monohydrate, C5H6N5O+·H2O3P−·H2O, guaninium monohydrogenphosphite dihydrate, C5H6N5O+·H2O3P−·2H2O, and guaninium dihydrogenmonophosphate monohydrate, C5H6N5O+·H2O4P−·H2O, are described and compared. The crystal structures have been determined from accurate single-crystal X-ray data sets collected at 100 (2) K. The two phosphite salts are monoclinic, space group P21/c, with different packing and the monophosphate salt is also monoclinic, space group P21/n. An investigation of the hydrogen-bond network in these guaninium salts reveals the existence of two ketoamine tautomers, the N9H form and an N7H form.

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