Synthesis and Mesophase Properties of a Series of Chiral Rod-Like Polysiloxanes

2011 ◽  
Vol 181-182 ◽  
pp. 123-126
Author(s):  
Hao Wu ◽  
Chun Xiu Zhang ◽  
Jia Ling Pu ◽  
Ya Nan Li ◽  
Ming Xia Zhang ◽  
...  
Keyword(s):  
Thin Films ◽  
Differential Scanning Calorimetry ◽  
Liquid Crystals ◽  
Cholesteryl Ester ◽  
Bragg Reflection ◽  
Helical Structure ◽  
Side Chain ◽  
Scanning Calorimetry ◽  
Grafting Polymerization ◽  
Molar Ratios

Cholesteric liquid crystals elastomers have been extensively studied during the last two decades. They showed Bragg-reflection in visible, Infrared and even UV wavelength Range and a particular circular polarization. Their special helical structure and the adjustment of pitch made them suitable for using as optical thin films. In this study, two kinds of mesogenic monomers undecylenate cholesteryl ester (M1) and p-phenylene di-4-(allyloxyl) benzoate (M2) were synthesized. Then the two monomers were fixed onto poly- (methylsiloxane) backbone by grafting polymerization using Dicyclopentadienylplatinum (II) Chloride as catalyst. A series of side-chain polymers with different monomer densities produced by the reaction of hydropolysiloxane and M1/M2with different molar ratios were obtained. The synthesized polymers were characterized by IR, H1NMR and GPC. The mesophases were characterized by using differential scanning calorimetry (DSC), polarizing optical microscopy (POM).

Synthesis and Mesomorphic Properties of a Series of Cholesteric Liquid Crystals

2010 ◽  
Vol 663-665 ◽  
pp. 759-762 ◽  
Author(s):  
Qing Lan Ma ◽  
Yuan Ming Huang
Keyword(s):  
Phase Transition ◽  
Differential Scanning Calorimetry ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
Optical Microscopy ◽  
Scanning Calorimetry ◽  
Polarized Optical Microscopy ◽  
Phase Transition Temperatures ◽  
Second Category ◽  
Mesomorphic Properties

A series of cholesterol liquid crystal compounds was synthesized. Phase-transition temperatures and mesomorphic textures of these synthesized compounds were characterized with differential scanning calorimetry and polarized optical microscopy, respectively. In these molecules the terminal ester chains CnH2n-1COO-, where n was the number of carbon atoms in the terminal ester chains, were linked to the cholesterol core. All of the synthesized cholesterol compounds exhibited mesophases for the first heating. However, as temperature decreased from their clearing points, their micrographs can also be divided into two categories, the first category exhibits branch-like mesophase textures for n in the range of 1-10 while the second category exhibits branch-like crystal textures for n in the range of 11-18.

Differential scanning calorimetry studies of the effect of Cu on the A1 to L10 transformation in FePt thin films

2005 ◽  
Vol 53 (4) ◽  
pp. 423-428 ◽  
Author(s):  
D.C. Berry ◽  
J. Kim ◽  
K. Barmak ◽  
K. Wierman ◽  
E.B. Svedberg ◽  
...  
Keyword(s):  
Thin Films ◽  
Differential Scanning Calorimetry ◽  
Scanning Calorimetry ◽  
Fept Thin Films

Monitoring the chemical heterogeneity of metallocenecatalysed copolymers of ethylene and higher 1-olefins using CRYSTAF and SEC-FTIR

e-Polymers ◽  
2003 ◽  
Vol 3 (1) ◽  
Author(s):  
Sven M. Graef ◽  
Robert Brüll ◽  
Harald Pasch ◽  
Udo M. Wahner
Keyword(s):  
Differential Scanning Calorimetry ◽  
Size Exclusion Chromatography ◽  
Catalyst System ◽  
Size Exclusion ◽  
Side Chain ◽  
Chemical Heterogeneity ◽  
Scanning Calorimetry ◽  
Crystallisation Temperature ◽  
Exclusion Chromatography

Abstract Copolymers of ethylene with 1-decene, 1-tetradecene and 1-octadecene were prepared using the catalyst system racEt[Ind]2ZrCl2/MAO and were analysed with regard to chemical heterogeneity using crystallisation analysis fractionation (CRYSTAF), differential scanning calorimetry (DSC) and size exclusion chromatography coupled to FTIR (SEC-FTIR). The melting and crystallisation temperatures from DSC decrease linearly with increasing amount of comonomer, independently of the nature thereof. The decrease in crystallisation temperature from CRYSTAF of copolymers with higher 1-olefin content indicates a small dependence on the length of the side chain. The chemical heterogeneity of the copolymers as analysed by DSC and CRYSTAF broadens with increasing comonomer concentration.

The Preparation and Characteristic Research of Keratin Powder Based on TCEP

2014 ◽  
Vol 1053 ◽  
pp. 438-443
Author(s):  
Jian Yong Liu ◽  
Jie Wang ◽  
Hao Ming Li
Keyword(s):  
Differential Scanning Calorimetry ◽  
Fourier Transform ◽  
Moisture Content ◽  
Helical Structure ◽  
Ftir Analysis ◽  
Dsc Analysis ◽  
Scanning Calorimetry ◽  
Β Sheet ◽  
Melting Peak Temperature ◽  
Wool Keratin

In this paper, the wool was pretreated by TCEP (Tris (2-carboxyethyl) phosphine) a certain time, and then prepared wool keratin powder by mechanical lapping. The characteristics of the keratin powder carried out by Fourier transform infrared (FTIR) and Differential scanning calorimetry (DSC). From the FTIR analysis, TCEP first role in α-helical structure of wool, making its decline, and then acting on β-sheet. From the DSC analysis, the melting peak temperature of α-crystalline with the time of TCEP effect on wool, presenting the trend of first increased and then drophave. Dissolved the keratin powder in 88% formic acid, then keratin films were maded.The characteristics of the keratin films were measured, the moisture content of keratin film increases with the time of wool treated with TCEP. And the dissolution rate and ultimate strength in line with the change of FTIR and DSC analysis results.

scholarly journals Preparation of (Pb,Ba)TiO3 powders and highly oriented thin films by a sol-gel process

2004 ◽  
Vol 19 (5) ◽  
pp. 1492-1498 ◽  
Author(s):  
Stacey W. Boland ◽  
Suresh C. Pillai ◽  
Wein-Duo Yang ◽  
Sossina M. Haile
Keyword(s):  
Thin Films ◽  
Sol Gel ◽  
Chelating Agent ◽  
Titanium Isopropoxide ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Force Microscopy ◽  
Molar Ratios ◽  
Atomic Force ◽  
Sol Gel Process

Solid solution Pb1-xBaxTiO3, with particular emphasis on Pb0.5Ba0.5TiO3, was prepared using a sol-gel process incorporating lead acetate trihydrate, barium acetate, and titanium isopropoxide as precursors, acetylacetone (2,4 pentanedione) as a chelating agent, and ethylene glycol as a solvent. The synthesis procedure was optimized by systematically varying acetylacetone: Ti and H2O:Ti molar ratios and calcination temperature. The resulting effects on sol and powder properties were studied using thermogravimetric analysis/differential scanning calorimetry, Fourier transform infrared spectroscopy, Brunauer-Emmett-Teller analysis, and x-ray diffraction (XRD). Crystallization of the perovskite structure occurred at a temperature as low as 450 °C. Thin films were prepared by spin coating on (100) MgO. Pyrolysis temperature and heating rate were varied, and the resultant film properties investigated using field-emission scanning electron microscopy, atomic force microscopy, and XRD. Under optimized conditions, highly oriented films were obtained at a crystallization temperature of 600 °C.

Cluster-Crosslinked Inorganic-Organic Hybrid Polymers: Influence of the Cluster Type on the Materials Properties

2002 ◽  
Vol 726 ◽  
Author(s):  
Silvia Gross ◽  
Vito Di Noto ◽  
Guido Kickelbick ◽  
Ulrich Schubert
Keyword(s):  
Differential Scanning Calorimetry ◽  
Thermogravimetric Analysis ◽  
Structural Features ◽  
Polymer Chains ◽  
Scanning Calorimetry ◽  
Hybrid Polymers ◽  
Materials Properties ◽  
Molar Ratios ◽  
Organic Hybrid ◽  
Cluster Type

AbstractMethacrylate-substituted tetranuclear tantalum, zirconium and titanium oxide clusters (Zr4O2(OMc)12, Ti4O2(OPri)6(OMc)6, and Ta4O4(OEt)8(OMc)4) were prepared by reaction of the alkoxides with methacrylic acid. The clusters were then polymerized with methyl methacrylate as co-monomers in different molar ratios (0.5–2 mol% of the functionalized cluster). In the resulting inorganic-organic hybrid polymers, the clusters crosslink the polymer chains very efficiently. The physical properties and structural features of the hybrid polymers, investigated by their swelling behavior, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), 13C MAS NMR and impedance spectroscopy, exhibit a clear dependence on the cluster portion in the polymer and on the cluster type.

In-Situ Characterisation of Precipitation in AI-Cu thin films

1999 ◽  
Vol 562 ◽  
Author(s):  
J. P. Lokker ◽  
A. J. Bottger ◽  
G. C. A. M. Janssen ◽  
S. Radelaar
Keyword(s):  
Thin Films ◽  
Differential Scanning Calorimetry ◽  
Bulk Material ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Enthalpy Changes ◽  
Thin Foils ◽  
Lower Temperature

ABSTRACTThe precipitate formation occurring in Al-Cu thin foils with copper concentrations of either 1.15 at.% or 0.3 at.%, has been studied. In-situ X-ray diffraction analysis and differential scanning calorimetry are applied to determine the phases formed and the enthalpy changes in the same samples. Both X-ray diffraction and differential scanning calorimetry indicate that the precipitation behaviour of thin films (about 500 nm thickness) differs significantly from that of bulk material. In the films studied the precipitation of Al2Cu occurs at a much lower temperature than expected on the basis of the (bulk) phase diagram. Moreover, no intermediate phases are observed prior to Al2Cu precipitation. Also the amount of Cu in solid solution (0.20 at%Cu) observed by electron-probe micro-analysis after slowly cooling from 500°C to room temperature, exceeds the solubility of bulk Al-Cu.

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