scholarly journals An NMR Investigation of Phase Structure and Chain Dynamics in the Polyethylene/Montmorillonite Nanocomposites

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Wei Li ◽  
Linxi Hou ◽  
Zhongren Chen
Keyword(s):  
Phase Structure ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Chain Dynamics ◽  
Chain Mobility ◽  
The Difference ◽  
Angle Spinning ◽  
Cp Mas Nmr

Novel exfoliated and interacted polyethylene (PE)/montmorillonite (MMT) nanocomposites prepared byin situpolymerization were characterized by solid-state nuclear magnetic resonance (NMR). The phase structure and molecular mobility were investigated by proton and carbon NMR under static and magic-angle spinning (MAS) conditions. The results showed that incorporation of MMT layer enhanced the polyethylene crystallinity behavior. The chain mobility of crystalline phase, interphase and amorphous phase was hindered in the nanocomposites. The phase structure and chain dynamics were also investigated upon changing the temperature. The orthorhombic and monoclinic phases were detected according to the13CP/MAS NMR. Quantitative characterization of the phase structure was also conducted by13C DP/MAS upon changing the temperature. Finally, the difference in the phase structure and chain dynamics in each phase of PE/nanocomposites was compared based on the NMR results when fiber filler was introduced.

Preparation, Characterization of Cellulose Fibers Grafting by β-Cyclodextrin and their Application for Antibacterial Products

2014 ◽  
Vol 936 ◽  
pp. 784-788 ◽  
Author(s):  
Chao Dong ◽  
Ying Ye ◽  
Li Ying Qian ◽  
Bei Hai He ◽  
Hui Ning Xiao
Keyword(s):  
Inclusion Complexes ◽  
Cellulose Fiber ◽  
Cellulose Fibers ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Food Chemistry ◽  
Cross Polarization ◽  
Angle Spinning ◽  
Cp Mas Nmr

Cyclodextrins (CDs) can form inclusion complexes with a variety of molecules making them very attractive in different areas, such as pharmaceutics, biochemistry, food chemistry and papermaking. In this communication the preparation of β-cyclodextrin-grafted cellulose fibers was carried out by reacting β-cyclodextrin with cellulose fiber via citric acid (CA). Both fourier transform infrared (FTIR) and cross polarization magic angle spinning solid state nuclear magnetic resonance (CP-MAS NMR) indicated that β-CDs had been chemically attached to cellulose backbone through the formation of ester bonds. Furthermore, the β-CD-grafted cellulose fibers formed inclusion complexes with ciprofloxacin hydrochloride (CipHCl). And the β-CD-grafted cellulose fibers loaded with CipHCl showed excellent antibacterial activity against E.coli and S.aureus.

scholarly journals In Situ Structural Characterization of a Recombinant Protein in Native Escherichia coli Membranes with Solid-State Magic-Angle-Spinning NMR

2011 ◽  
Vol 133 (32) ◽  
pp. 12370-12373 ◽  
Author(s):  
Riqiang Fu ◽  
Xingsheng Wang ◽  
Conggang Li ◽  
Adriana N. Santiago-Miranda ◽  
Gary J. Pielak ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Solid State ◽  
Recombinant Protein ◽  
Structural Characterization ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Angle Spinning

scholarly journals Synthesis and structural characterization of neutral hexacoordinate silicon(IV) complexes containing salophen and thiocyanato-N ligands

2018 ◽  
Vol 41 (5-6) ◽  
pp. 135-141
Author(s):  
Gerardo González-García ◽  
Astrid Pérez ◽  
Jorge A. López ◽  
Esneyder Puello-Polo ◽  
Andrés González-García
Keyword(s):  
Solid State ◽  
Magic Angle Spinning ◽  
Mas Nmr ◽  
Magic Angle ◽  
H Nmr ◽  
Elemental Analyses ◽  
Molar Equivalent ◽  
Angle Spinning ◽  
Cp Mas Nmr

Abstract The reaction of the H2salophen ligand, 2,2′-((1E,1′E)-(1,2-phenylenebis(azanylylidene))bis (methanylylidene))diphenol, with one molar equivalent of Si(NCS)4, MeSi(NCS)3 (13), or HMeSi(NCS)2 afforded neutral hexacoordinate silicon complexes, which have an-NCS bi-functionality (complex 1) and mono-functionality (complex 14). The reaction of Si(NCS)4 with the H2salophen-type ligand1,1′-((1E,1′E)-(1,2-phenylenebis(azanylylidene))bis(methanylylidene)) bis(naphthalen-2-ol) (H2Noph), afforded the hexacoordinate silicon complex 15, which has an-NCS bi-functionality. Single-crystal X-ray structural and elemental analyses were used to characterize and confirm the structure of the starting material 13 and complexes 1, 14, and 15. The complexes were characterized in solution by 1H, 13C, and silicon-29 nuclear magnetic resonance (29Si NMR) and in the solid state by 29Si cross-polarization/magic angle spinning (CP/MAS) NMR. Because of the poor solubility of complex 1, it was only possible to characterize it in the solid state by 13C and 29Si CP/MAS NMR and in solution by 1H NMR.

Development and application of novel NMR methodologies for the in situ characterization of crystallization processes of metastable crystalline materials

2017 ◽  
Vol 232 (1-3) ◽  
Author(s):  
Leo van Wüllen ◽  
Jan Gerrit Schiffmann ◽  
Jakob Kopp ◽  
Zhongqing Liu ◽  
Holger Kirchhain ◽  
...  
Keyword(s):  
Magic Angle Spinning ◽  
Magic Angle ◽  
In Situ Characterization ◽  
Sample Rotation ◽  
Angle Spinning ◽  
Equilibrium Phases ◽  
Fast Magic Angle Spinning ◽  
Centripetal Forces

AbstractIn this contribution we report on the development and application of modern NMR approaches for the in situ characterization of the crystallization of metastable materials. The work was performed within the framework of the DFG priority programme SPP 1415 “Crystalline Non-Equilibrium Phases”. As one of the goals of this project, the development of a NMR methodology which enables an analysis of local structural motifs on short (1–2 Å) and extended (2–6 Å) length scales without the need for fast magic angle spinning (MAS) has been defined, since the enormous centripetal forces which occur during fast sample rotation (up to 10

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