scholarly journals The Effect of Molecular Isomerism on the Barrier Properties of Polyimides: Perspectives from Experiments and Simulations

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1749
Author(s):  
Yiwu Liu ◽  
Fengyun Xie ◽  
Jie Huang ◽  
Jinghua Tan ◽  
Chengliang Chen ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Positron Annihilation ◽  
High Performance ◽  
Barrier Properties ◽  
Chain Structure ◽  
X Ray Diffraction ◽  
Gas Barrier ◽  
X Ray ◽  
Design And Synthesis ◽  
Barrier Polymers

A novel carbazole-containing diamine (M-2,7-CPDA) isomer of our previously reported diamine 2,7-CPDA, has been synthesized using a two-step synthesis. Compared with 2,7-CPDA, the substituted position of amino is changed from para to meta for M-2,7-CPDA. The two diamines were polymerized with pyromellitic dianhydride (PMDA) to prepare two isomeric polyimides (M-2,7-CPPI and 2,7-CPPI), respectively. The effects of para/meta isomerism on microstructures and gas barrier performances of the two isomeric polyimides were studied by positron annihilation test, X-ray diffraction and molecular simulation. The results display that meta-connected M-2,7-CPPI has less ordered chain structure and weaker hydrogen bonding than para-connected 2,7-CPPI, which leads to loose chain stacking and thereby increased free volumes of M-2,7-CPPI. The higher free volumes promote the solubility and diffusivity of gas in M-2,7-CPPI. As a result, the meta-linked M-2,7-CPPI shows a lower gas barrier than its para-linked analog. The work provides guidance for the design and synthesis of high-performance barrier polymers.

Synthesis and Structural Characterization of a Cu(II) Coordination Polymer from N1,N2-Di(pyridin-4-yl)oxalamide

2014 ◽  
Vol 69 (9-10) ◽  
pp. 1045-1049
Author(s):  
Hai-Wei Kuai ◽  
Tao Hu ◽  
Ding-Yun Jiang ◽  
Yun-Hua Qian ◽  
Deng-Hao Li
Keyword(s):  
Hydrogen Bonding ◽  
Ir Spectroscopy ◽  
Coordination Polymer ◽  
Chain Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Triclinic System ◽  
A Chain ◽  
2D Network

Abstract The reaction of Cu(NO3)2·3H2O with N1,N2-di(pyridin- 4-yl)oxalamide (L) and KSCN in the presence of DMF by the layering method gives rise to a new complex [Cu(L2)(SCN)2(DMF)2]n (1). Complex 1 has been characterized by single-crystal and powder X-ray diffraction, IR spectroscopy, and elemental and thermogravimetric analyses. It crystallizes in the triclinic system with space group P1̅ and shows a chain structure. Delicate N-H···O hydrogen bonding exists in individual units, and adjacent chains are linked by intermolecular interactions, resulting in an extended 2D network.

Syntheses, Structure, and Properties of the Dimer Cu(DMAP)4(ClO4)2 (DMAP = 4-N, N-Dimethylaminopyridine)

2011 ◽  
Vol 688 ◽  
pp. 296-300 ◽  
Author(s):  
Li Wang ◽  
Dong Ping Sun
Keyword(s):  
Hydrogen Bonding ◽  
Rational Design ◽  
Three Dimensional ◽  
X Ray Diffraction ◽  
Supramolecular Systems ◽  
Coordination Networks ◽  
X Ray ◽  
Design And Synthesis ◽  
Infinite Network ◽  
Polymeric Coordination

The rational design and synthesis of discrete coordination architectures or polymeric coordination networks has received much attention recently, and hydrogen bonding andp-pstacking interactions are often employed in their construction. In this text, a strongly hydrogen-bonded dimer of the Cu(II) of 4-N, N-dimethylaminopyridine (DMAP), Cu(DMAP)4(ClO4)2, was synthesized and characterized by single crystal X-ray diffraction, UV-Vis and IR spectroscopy. X-ray analysis indicates that this compound is a dimer structure and the coordination geometries around the two Cu(II) centers could be described as distorted octahedrons. In addition, the ClO4-anions are involved in hydrogen bonding connecting the dimeric units to give a three dimensional infinite network. The extension of this work to a similar type of supramolecular systems may be fundamental to the study of the bonding interactions present in the solid state.

scholarly journals Enhancement of Chloroprene/Natural/Butadiene Rubber Nanocomposite Properties Using Organoclays and Their Combination with Carbon Black as Fillers

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1085
Author(s):  
Patricia Castaño-Rivera ◽  
Isabel Calle-Holguín ◽  
Johanna Castaño ◽  
Gustavo Cabrera-Barjas ◽  
Karen Galvez-Garrido ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Black ◽  
High Performance ◽  
Rubber Matrix ◽  
Butadiene Rubber ◽  
X Ray Diffraction ◽  
X Ray ◽  
Rubber Blends ◽  
Ft Ir ◽  
Chloroprene Rubber

Organoclay nanoparticles (Cloisite® C10A, Cloisite® C15) and their combination with carbon black (N330) were studied as fillers in chloroprene/natural/butadiene rubber blends to prepare nanocomposites. The effect of filler type and load on the physical mechanical properties of nanocomposites was determined and correlated with its structure, compatibility and cure properties using Fourier Transformed Infrared (FT-IR), X-ray Diffraction (XRD), Thermogravimetric Analysis (TGA) and rheometric analysis. Physical mechanical properties were improved by organoclays at 5–7 phr. Nanocomposites with organoclays exhibited a remarkable increase up to 46% in abrasion resistance. The improvement in properties was attributed to good organoclay dispersion in the rubber matrix and to the compatibility between them and the chloroprene rubber. Carbon black at a 40 phr load was not the optimal concentration to interact with organoclays. The present study confirmed that organoclays can be a reinforcing filler for high performance applications in rubber nanocomposites.

scholarly journals Exploring the Structural Chemistry of Pyrophosphoramides: N,N′,N″,N‴-Tetraisopropylpyrophosphoramide

Chemistry ◽  
2021 ◽  
Vol 3 (1) ◽  
pp. 149-163
Author(s):  
Duncan Micallef ◽  
Liana Vella-Zarb ◽  
Ulrich Baisch
Keyword(s):  
Crystal Structure ◽  
Mass Spectrometry ◽  
Nuclear Magnetic Resonance ◽  
Hydrogen Bonding ◽  
Nmr Spectroscopy ◽  
Ir Spectroscopy ◽  
Room Temperature ◽  
Intermolecular Hydrogen Bonding ◽  
X Ray Diffraction ◽  
X Ray

N,N′,N″,N‴-Tetraisopropylpyrophosphoramide 1 is a pyrophosphoramide with documented butyrylcholinesterase inhibition, a property shared with the more widely studied octamethylphosphoramide (Schradan). Unlike Schradan, 1 is a solid at room temperature making it one of a few known pyrophosphoramide solids. The crystal structure of 1 was determined by single-crystal X-ray diffraction and compared with that of other previously described solid pyrophosphoramides. The pyrophosphoramide discussed in this study was synthesised by reacting iso-propyl amine with pyrophosphoryl tetrachloride under anhydrous conditions. A unique supramolecular motif was observed when compared with previously published pyrophosphoramide structures having two different intermolecular hydrogen bonding synthons. Furthermore, the potential of a wider variety of supramolecular structures in which similar pyrophosphoramides can crystallise was recognised. Proton (1H) and Phosphorus 31 (31P) Nuclear Magnetic Resonance (NMR) spectroscopy, infrared (IR) spectroscopy, mass spectrometry (MS) were carried out to complete the analysis of the compound.

scholarly journals The crystal structures and mechanical properties of the uranyl carbonate minerals roubaultite, fontanite, sharpite, widenmannite, grimselite and čejkaite

2020 ◽  
Vol 7 (21) ◽  
pp. 4197-4221 ◽  
Author(s):  
Francisco Colmenero ◽  
Jakub Plášil ◽  
Jiří Sejkora
Keyword(s):  
Mechanical Properties ◽  
Hydrogen Bonding ◽  
Diffraction Pattern ◽  
Crystal Structures ◽  
First Principles ◽  
X Ray Diffraction ◽  
Carbonate Minerals ◽  
X Ray ◽  
Uranyl Carbonate

The structure, hydrogen bonding, X-ray diffraction pattern and mechanical properties of six important uranyl carbonate minerals, roubaultite, fontanite, sharpite, widenmannite, grimselite and čejkaite, are determined using first principles methods.

scholarly journals Hydrogen bonding in melamine compounds of amino acids

2014 ◽  
Vol 70 (a1) ◽  
pp. C534-C534
Author(s):  
Nasreddine Ghouari ◽  
Nourreedine Benali-Cherif
Keyword(s):  
Amino Acids ◽  
Hydrogen Bonding ◽  
Nitric Acid ◽  
Organic Cation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hybrid Compounds ◽  
Amino Butyric Acid ◽  
3D Network ◽  
Bonding Electron

The theme of this work is part of the study of intermolecular interactions that hold the crystal structures of hybrid compounds based sulphuric acid, nitric acid, Melamine, Diethylamine, L-(+) - glutamic acid, DL-2-amino butyric acid. The aim of this work is to enlarge our laboratory researches [1-3] and methods in synthesis of new hybrid compounds consisting in organic cation(s) and mineral anion(s). We have obtained single crystals of a few samples after several trials and we plan to synthesize and characterize these crystals by X-ray diffraction, FTIR and Raman. The crystals structures allow us to study the 3D network hydrogen bonding, electron density and collect several other informations useful in FTIR and Raman studies of these hybrid compounds.

A New Organic-Inorganic Hybrid Based on L-Arginine and Polyoxoanion

2015 ◽  
Vol 1105 ◽  
pp. 335-338
Author(s):  
Qiong Wu ◽  
Jing Lu ◽  
Xiao Lin Ji ◽  
Tao Yu Zou ◽  
Zhen Fang Qiao ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Sodium Cation ◽  
Water Molecules ◽  
X Ray Diffraction ◽  
Inorganic Hybrid ◽  
X Ray ◽  
Hydrogen Bonding Interactions ◽  
Photocatalytic Activities ◽  
Metal Organic ◽  
Supramolecular Networks

Modifying polyoxometalates with organic and/or metal-organic moieties is a widely adopted method for broading the range of properties. In this work a new polyoxometalate constructed from Anderson-type polyoxoanions and L-arginine (Arg =L-arginine) molecules Na [CrMo6(OH)6O18]}(H2Arg)2·8H2O(1) has been synthesized via conventional method and characterized by routine techniques. Single-crystal X-Ray diffraction analysis shows that compound 1 is constructed by chiralL-arginine grafted Anderson-type clusters, sodium cation and water molecules which are further stabilized by hydrogen bonding interactions constitute 3D supramolecular networks. In addition, both antitumor behavior and photocatalytic activities of compound 1 were investigated.

Syntheses, Structural Characterization and Fluorescence of Zn(II) and Cd(II) Polymers from 5-(Pyridin-2-ylmethylamino)isophthalic acid

2013 ◽  
Vol 68 (9) ◽  
pp. 1007-1014 ◽  
Author(s):  
Xiao-Chun Cheng ◽  
Xiao-Hong Zhu ◽  
Hai-Wei Kuai
Keyword(s):  
Water Clusters ◽  
Hydrothermal Reaction ◽  
Reaction System ◽  
Chain Structure ◽  
Isophthalic Acid ◽  
Auxiliary Ligand ◽  
X Ray Diffraction ◽  
X Ray ◽  
Alkaline Reaction ◽  
A Chain

The hydrothermal reaction of Zn(II) nitrate with 5-(pyridin-2-ylmethylamino)isophthalic acid (H2L) yields the complex [Zn(L)(H2O)] 2H2O (1). When 2,2'-bipyridine (bpy) as auxiliary ligand and Cd(II) nitrate were used in the alkaline reaction system, [Cd(L)(H2O)(bpy)] 3H2O (2) was obtained. Complexes 1 and 2 have been characterized by single-crystal and powder X-ray diffraction, IR, elemental and thermogravimetric analyses. Complex 1 shows a 2D fes network structure with uninodal 3-connected (4.82) topology, which is further linked by hydrogen bonding to give rise to a 3D supramolecular framework; complex 2 displays a chain structure. Interestingly, tetranuclear water clusters were generated in 1, which are interlinked to fabricate a water chain structure. The fluorescence properties of 1 and 2 were investigated

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