Wide-angle X-ray diffraction and differential scanning calorimetry study of the crystallization of poly(ethylene naphthalate), poly(butylene naphthalate), and their copolymers

2004 ◽  
Vol 42 (5) ◽  
pp. 843-860 ◽  
Author(s):  
George Z. Papageorgiou ◽  
George P. Karayannidis ◽  
Dimitris N. Bikiaris ◽  
Anagnostis Stergiou ◽  
George Litsardakis ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Wide Angle ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Differential Scanning Calorimetry Study ◽  
X Ray ◽  
Poly Ethylene

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.

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.

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

Plasticizer effect on melt blending of polylactide stereocomplex

e-Polymers ◽  
2017 ◽  
Vol 17 (5) ◽  
pp. 409-416 ◽  
Author(s):  
Yottha Srithep ◽  
Dutchanee Pholharn
Keyword(s):  
Thermal Stability ◽  
Differential Scanning Calorimetry ◽  
Crystallization Rate ◽  
Wide Angle ◽  
Melt Blending ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Neat Plla ◽  
Internal Mixer

AbstractPoly(l-lactide) (PLLA)/poly(d-lactide) (50/50) with plasticizer contents ranging from 2% to 16% w/w were prepared by melt blending using an internal mixer. Wide-angle X-ray diffraction, Fourier transform infrared spectroscopy and differential scanning calorimetry results confirmed that complete stereocomplex polylactide crystallites without any homocrystallites were produced. Compared to neat PLLA, the melting temperature of the stereocomplex polylactide and its plasticized samples was approximately 55°C higher. Higher plasticizer contents decreased glass transition temperature of the stereocomplex, which implied higher flexibility and enhanced the crystallization rate. However, the plasticizer in the stereocomplex reduced the thermal stability.

scholarly journals A simultaneous X-ray diffraction–differential scanning calorimetry study into the phase transitions of mefenamic acid

2019 ◽  
Vol 52 (6) ◽  
pp. 1264-1270 ◽  
Author(s):  
Yuying Pang ◽  
Asma Buanz ◽  
Richard Telford ◽  
Oxana V. Magdysyuk ◽  
Simon Gaisford ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Mefenamic Acid ◽  
Cell Expansion ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Differential Scanning Calorimetry Study ◽  
Polymorphic Transitions ◽  
X Ray ◽  
New Form ◽  
The Stability

In this study, the polymorphic transitions of mefenamic acid (MA) were studied by synchrotron X-ray powder diffraction combined with differential scanning calorimetry (XRD-DSC). The initial material was found to be phase-pure form I which, when heated, produces two endotherms that can be observed by DSC at 162.72 and 219.55°C. The former was found to correspond to a solid–solid enantiotropic transition from form I to a mixture of forms II and III. The latter is the melting point of form II. As form I is heated, significantly greater unit-cell expansion is seen in the a direction than in b and c, which can be explained by the stronger intermolecular interactions in the bc plane. Refinements of the reported MA structures against the patterns collected during heating revealed that at 175°C there exists a mixture of forms I, II and III, whereas only forms II and III remain at 205°C. However, reflections are observed at both temperatures which cannot be fitted with the known forms of MA. It is hypothesized that a new form of MA is produced upon heating. The stability of MA after the enantiotropic transition temperature is II > III > I, which differs from the previously reported II > I > III.

Gelation Crystallization of Poly(L-Lactide) in Solvents of Varying Molecular Size

2007 ◽  
Vol 15 (5) ◽  
pp. 389-393
Author(s):  
Hong Hao ◽  
Guozheng Liang ◽  
Junmin Zhao
Keyword(s):  
Differential Scanning Calorimetry ◽  
Ethylene Glycol ◽  
Crystallization Rate ◽  
Molecular Size ◽  
Large Molecule ◽  
X Ray Diffraction ◽  
Poly Ethylene Glycol ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Poly Ethylene

The crystallization behaviour of poly(L-lactide) (PLLA) samples prepared in large-molecule solvents, such as poly(ethylene glycol) (PEG), was studied by differential scanning calorimetry (DSC) and X-ray diffraction. The results indicate that those samples recovered from large-molecule solvents exhibit higher crystallinity, non-isothermal crystallization temperature and faster crystallization rate than the ones crystallized in a small-molecule solvent. The crystallinity of samples from PLLA/PEG gel is about 73% measured by the DSC. The molar size of the solvent has a large influence on the formation of helical conformations and, thereby on the crystallization rate of PLLA in solution.

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