Crosslinking and Mechanical Properties of Liquid Rubber. I. Curative Effect of Aliphatic DIOLS

1979 ◽  
Vol 52 (5) ◽  
pp. 920-948 ◽  
Author(s):  
Yuji Minoura ◽  
Shinzo Yamashita ◽  
Hiroshi Okamoto ◽  
Tadao Matsuo ◽  
Michiaki Izawa ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Low Molecular Weight ◽  
Structure Property ◽  
X Ray Diffraction ◽  
Curative Effect ◽  
Polyurethane Elastomers ◽  
X Ray ◽  
Structure Property Relationships ◽  
The Difference

Abstract The structure-property relationships of polyurethane elastomers derived from a liquid hydroxyl-terminated polybutadiene/low molecular weight aliphatic diol/diisocyanate system were studied. The effects of the amount of low molecular weight diol on the mechanical properties of the elastomer were discussed on the basis of the results of stress-strain, swelling, dynamic viscoelasticity, x-ray diffraction, etc. It was found that some particular combinations of low molecular weight diol and diisocyanate specifically affect the properties of elastomers. When the mechanical properties of the elastomers were plotted against the number of methylene carbons in the low molecular weight diol, characteristic zigzag patterns were obtained. These patterns were explained by the difference in the packing and the dependence of the strength of intermolecular hydrogen bonding on whether the number of the methylene carbons was even or odd. This assumption was confirmed by x-ray diffraction.

Low Molecular Weight Microfibers with Light Sensing Properties

2017 ◽  
Vol 54 (4) ◽  
pp. 655-658
Author(s):  
Andrei Bejan ◽  
Dragos Peptanariu ◽  
Bogdan Chiricuta ◽  
Elena Bicu ◽  
Dalila Belei
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight ◽  
X Ray Diffraction ◽  
Aromatic Rings ◽  
X Ray ◽  
Force Microscopy ◽  
Light Sensing ◽  
Sensing Applications ◽  
Atomic Force ◽  
Low Molecular Weight Compounds

Microfibers were obtained from organic low molecular weight compounds based on heteroaromatic and aromatic rings connected by aliphatic spacers. The obtaining of microfibers was proved by scanning electron microscopy. The deciphering of the mechanism of microfiber formation has been elucidated by X-ray diffraction, infrared spectroscopy, and atomic force microscopy measurements. By exciting with light of different wavelength, florescence microscopy revealed a specific optical response, recommending these materials for light sensing applications.

Structure/Property Relationships of Seashells

2004 ◽  
Vol 844 ◽  
Author(s):  
David J. Scurr ◽  
Stephen J. Eichhorn
Keyword(s):  
Raman Band ◽  
Surface Damage ◽  
Structure Property ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structure Property Relationships ◽  
Energy Variable ◽  
Insight Into ◽  
Characterisation Techniques ◽  
Scanning Electron

ABSTRACTThis study uses various characterisation techniques on the razor shell (Ensis siliqua), to relate the shell's microstructure to its mechanical properties. Scanning electron microscopy (SEM) has shown that the outer and inner regions of the shell are composed of simple and complex crossed lamellar microstructures respectively. These layers are interspersed by prismatic layers of a completely different crystallographic orientation. Nanoindentation and microhardness measurements have shown that the structure is anisotropic, and Raman band shifts have been observed within these indented/deformed areas of shell, showing that the microstructure deforms rather than generating surface damage. The use of energy variable synchrotron X-ray diffraction has shown that the calcium carbonate crystals of the shell are preferentially orientated as a function of depth and that opposing residual stresses exist at the outer and inner regions of the shell. This study has analysed several microstructural features of the shell and provided an insight into how they prevent failure of the material.

Structure–property relationships in hybrid (C3H5N2)3[Sb2I9] and (C3H5N2)3[Bi2I9] isomorphs

2016 ◽  
Vol 3 (10) ◽  
pp. 1306-1316 ◽  
Author(s):  
M. Węcławik ◽  
A. Gągor ◽  
R. Jakubas ◽  
A. Piecha-Bisiorek ◽  
W. Medycki ◽  
...  
Keyword(s):  
Proton Magnetic Resonance ◽  
Optical Observations ◽  
Structure Property ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structure Property Relationships ◽  
Hybrid Crystals ◽  
Ft Ir ◽  
Two Hybrid ◽  
Ft Ir Spectroscopy

Two hybrid crystals imidazolium iodoantimonate(iii) and iodobismuthate(iii) have been synthesized and characterized in a wide temperature range (100–350 K) by means of X-ray diffraction, dielectric spectroscopy, proton magnetic resonance, FT-IR spectroscopy and optical observations.

scholarly journals Hydrogels formed from Fmoc amino acids

CrystEngComm ◽  
2015 ◽  
Vol 17 (42) ◽  
pp. 8047-8057 ◽  
Author(s):  
Emily R. Draper ◽  
Kyle L. Morris ◽  
Marc A. Little ◽  
Jaclyn Raeburn ◽  
Catherine Colquhoun ◽  
...  
Keyword(s):  
Amino Acids ◽  
Molecular Weight ◽  
Single Crystal ◽  
Crystal Structures ◽  
Diffraction Data ◽  
Low Molecular Weight ◽  
X Ray Diffraction ◽  
X Ray ◽  
Single Crystal Structures

A number of Fmoc amino acids can be effective low molecular weight hydrogelators; we compare single crystal structures to fibre X-ray diffraction data.

SYNTHESIS AND CHARACTERIZATION OF FARNESENE-BASED POLYMERS

2017 ◽  
Vol 90 (2) ◽  
pp. 308-324 ◽  
Author(s):  
Taejun Yoo ◽  
Steven K. Henning
Keyword(s):  
Molecular Weight ◽  
Anionic Polymerization ◽  
Molar Mass ◽  
Functional Materials ◽  
Synthesis And Characterization ◽  
Low Molecular Weight ◽  
Structure Property ◽  
Structure Property Relationships ◽  
By Products

ABSTRACT A bio-based route to the production of trans-β-farnesene has recently been commercialized. Trans-β-farnesene is capable of being polymerized by both anionic and cationic pathways, creating low molecular weight polymers with structure–property relationships unique within the diene class of monomers. Trans-β-farnesene is produced through fermentation of sugar feedstocks. The pathway offers an alternative to petroleum-based feedstocks derived as by-products of naphtha or ethane cracking. Anionic polymerization of the monomer produces a highly branched “bottlebrush” structure, with rheological properties that are markedly different than those of linear diene polymers. Specifically, a lack of entanglements is observed even at relatively high molar masses. For hydroxyl-terminated oligomers, Tg as a function of molar mass follows a trend opposite non-functional materials. The synthesis and characterization of trans-β-farnesene–based polymers will be presented, including anionically prepared low molecular weight diols and monols.

Polyethersulfone polymers and oligomers — Morphology and crystallization

2012 ◽  
Vol 90 (10) ◽  
pp. 880-890 ◽  
Author(s):  
Abdelkader Benhalima ◽  
François Hudon ◽  
Finda Koulibaly ◽  
Christian Tessier ◽  
Josée Brisson
Keyword(s):  
Molecular Weight ◽  
Model Compound ◽  
Crystal Form ◽  
Low Molecular Weight ◽  
Structural Studies ◽  
X Ray Diffraction ◽  
Crystal Forms ◽  
X Ray ◽  
Diphenyl Sulfone ◽  
Induced Crystallization

Crystal forms of polyethersulfones (PES) were investigated by using a model compound and a low molecular weight oligomer. These are amorphous as-synthesized, and can undergo solvent-induced crystallization under the appropriate conditions. The model compound, 4,4′-bis(p-methoxyphenoxy)diphenyl sulfone, yielded monocrystals, and its structure was solved using X-ray diffraction. Conformational disorder is present, two conformers cohabiting in 55:45 proportions. This model compound, combined to previous structural studies published in the literature, served as a basis for conformational studies of polyethersulfone. Low molecular weight polymers submitted to solvent-induced crystallization resulted in a PES crystal form different from that previously published in the literature, as shown by powder X-ray diffraction.

scholarly journals Characterization of the structure and composition of gecko adhesive setae

2005 ◽  
Vol 3 (8) ◽  
pp. 441-451 ◽  
Author(s):  
N.W Rizzo ◽  
K.H Gardner ◽  
D.J Walls ◽  
N.M Keiper-Hrynko ◽  
T.S Ganzke ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Molecular Weight ◽  
Electrophoretic Analysis ◽  
Low Molecular Weight ◽  
X Ray Diffraction ◽  
X Ray ◽  
Pattern Characteristic ◽  
Additional Protein ◽  
Adhesive Materials

The ability of certain reptiles to adhere to vertical (and hang from horizontal) surfaces has been attributed to the presence of specialized adhesive setae on their feet. Structural and compositional studies of such adhesive setae will contribute significantly towards the design of biomimetic fibrillar adhesive materials. The results of electron microscopy analyses of the structure of such setae are presented, indicating their formation from aggregates of proteinaceous fibrils held together by a matrix and potentially surrounded by a limiting proteinaceous sheath. Microbeam X-ray diffraction analysis has shown conclusively that the only ordered protein constituent in these structures exhibits a diffraction pattern characteristic of β-keratin. Raman microscopy of individual setae, however, clearly shows the presence of additional protein constituents, some of which may be identified as α-keratins. Electrophoretic analysis of solubilized setal proteins supports these conclusions, indicating the presence of a group of low-molecular-weight β-keratins (14–20 kDa), together with α-keratins, and this interpretation is supported by immunological analyses.

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