Cocrystallization phenomena in piperazine-based copolyamides as examined by differential scanning calorimetry, wide-angle X-ray diffraction, and solid-state NMR

2003 ◽  
Vol 41 (13) ◽  
pp. 2082-2094 ◽  
Author(s):  
Bert Vanhaecht ◽  
Jan Devroede ◽  
Rudolph Willem ◽  
Monique Biesemans ◽  
Wyjayanthi Goonewardena ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Solid State ◽  
Solid State Nmr ◽  
Wide Angle ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray

scholarly journals Influence of Molecular Orientation on the Melting Behavior of Poly(phenylene sulfide) Fibers

2013 ◽  
Vol 8 (3) ◽  
pp. 155892501300800
Author(s):  
Prabhakar Gulgunje ◽  
Gajanan Bhat ◽  
Joseph Spruiell
Keyword(s):  
Differential Scanning Calorimetry ◽  
Molecular Orientation ◽  
Polarized Light ◽  
Melting Behavior ◽  
Probable Mechanism ◽  
Wide Angle ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Phenylene Sulfide

The influence of molecular orientation on the melting behavior of draw-annealed poly(phenylene sulfide) fibers is investigated in the present paper. Tools used to probe the investigation were differential scanning calorimetry, polarized light optical microscopy, wide angle X-ray diffraction, and small angle X-ray diffraction. It is shown that molecular orientation in the crystalline and amorphous regions play a key role in crystal rearrangement during melting. A probable mechanism by which amorphous orientation influences crystal rearrangement is also discussed.

PHASE TRANSFORMATIONS DURING HEATING OF AMORPHOUS/NANOCRYSTALLINE Ni–Ti POWDERS

2010 ◽  
Vol 24 (09) ◽  
pp. 1137-1140 ◽  
Author(s):  
M. M. VERDIAN ◽  
M. SALEHI ◽  
K. RAEISSI
Keyword(s):  
Differential Scanning Calorimetry ◽  
Solid State ◽  
Phase Transformations ◽  
Low Energy ◽  
Heating Process ◽  
Study Phase ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Niti Phase

Amorphous/nanocrystalline 50 Ni –50 Ti powders were synthesized from elemental Ti and Ni powders by solid state synthesis utilizing low energy mechanical alloying with times up to 100 h. The produced powders were investigated by X-ray diffraction and differential scanning calorimetry to study phase transformations that occurred during heating in the calorimeter. It was found that at the first stage of the heating process, a disordered NiTi phase was formed at temperature of about 400°C. Further investigations indicated that this phase transformed into the Ni 3 Ti and Ti 2 Ni intermetallic compounds after heating at a temperature of about 800°C.

Physicochemistry of the Tomb of Nefertari, Egypt.

1988 ◽  
Vol 123 ◽  
Author(s):  
J. E. Smeaton ◽  
George Burns
Keyword(s):  
Differential Scanning Calorimetry ◽  
Sodium Chloride ◽  
Solid State ◽  
Kinetic Study ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Physicochemical Processes ◽  
Gypsum Dehydration

AbstractThe Tomb of Nefertari, no. 66, Valley of the Queens, is an internationally known monument of historic and artistic importance; it is considere d one of the most beautiful of the Royal Egyptian tombs. The fragility of its plaster along with its ubiquitous sodium chloride crystals and microcrystals have complicated its conservation and restoration. In order to determine the optimum pathway for its conservation, the physicochemical processes which occur now in this Tomb must be well understood. To improve this understanding, samples of plaster taken from the Tomb have been analyzed using Differential Scanning Calorimetry and X-ray Diffraction and have been shown to be fully dehydrated; previous findings suggest that this is not the case in all contemporary Royal tombs. Although we are not aware of any kinetic study of gypsum dehydration in the solid state, the presence of anhydrite in the Tomb of Nefertari suggests that the CaSO4 ·2H2O → CaSO4 + 2H2O reaction is catalyzed. It is reasoned that finely-dispersed sodium chloride crystals act as effective catalysts in this reaction.

scholarly journals Preparation and thermal decomposition of solid state cinnamates of alkali earth metals, except beryllium and radium

1998 ◽  
Vol 23 (0) ◽  
pp. 91-98 ◽  
Author(s):  
Ana Glauce ZAINA CHIARETTO ◽  
Marco Aurélio da Silva CARVALHO FILHO ◽  
Nedja Suely FERNANDES ◽  
Massao IONASHIRO
Keyword(s):  
Thermal Stability ◽  
Differential Scanning Calorimetry ◽  
Thermal Decomposition ◽  
Solid State ◽  
General Formula ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Preparation And Thermal Decomposition ◽  
Derivative Thermogravimetry

Solid state compounds of general formula ML2.nH2O [where M is Mg, Ca, Sr or Ba; L is cinnamate (C6H5 -CH=CH-COO-) and n = 2, 4, 0.8, 3 respectively], have been synthetized. Thermogravimetry (TG), derivative thermogravimetry (DTG), differential scanning calorimetry (DSC) and X-ray diffraction powder patterns have been used to characterize and to study the thermal stability and thermal decomposition of these compounds.

scholarly journals Phase Transition and Melt-Recrystallization Behavior of Poly(Butylene Adipate) Investigated by Simultaneous Measurements of Wide-Angle X-Ray Diffraction (WAXD) and Differential Scanning Calorimetry (DSC)

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 75
Author(s):  
Mengfan Wang ◽  
Weiyu Cao
Keyword(s):  
Phase Transition ◽  
Differential Scanning Calorimetry ◽  
Heating Process ◽  
Wide Angle ◽  
Melt Crystallization ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Β Phase ◽  
Simultaneous Measurements

Simultaneous measurements of wide-angle X-ray diffraction (WAXD) and differential scanning calorimetry (DSC) were carried out to investigate the phase transition and melting behaviors of poly(butylene adipate) (PBA). Thermal expansion changes along the a and b axes of the β form unit cell are different from each other during the heating process. At the beginning of the β to αH (high-temperature α phase) phase transition, the β phase melts very fast, while the recrystallization of the αH phase is delayed and slowed. With the further increment of the temperature, the melting rate of the β phase slows down, while the recrystallization of the αH phase accelerates. The diffraction peak intensity ratios of the β(020):β(110) and αH(020):αH(110) diffraction peaks during the first heating process have similar value. However, the above value is different from the value of α(020):α(110) during the following melt-crystallization process. This difference comes from the different orientations of the crystal lattices of the α and αH(β) crystals to the substrate plane, which indicates that the αH phase inherits the orientation of the β phase during phase transition and the orientation of αH form crystals is different from the α form crystals that crystallized from the melt.

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