Further Investigations of Crystal-to-Crystal Phase Transition of a [2]Pseudorotaxane Composed of Ferrocene-terminated Dialkylammonium and Dibenzo[24]crown-8-ether

CrystEngComm ◽  
2021 ◽  
Author(s):  
Yuji Suzaki ◽  
Yugo Fukuchi ◽  
Hiroko Tadami ◽  
Take-aki Koizumi ◽  
Kohtaro Osakada ◽  
...  
Keyword(s):  
Phase Transition ◽  
Low Temperature ◽  
Crystalline Phase ◽  
Crystal Phase ◽  
Β Phase ◽  
Α Phase ◽  
Crystal Phase Transition ◽  
Crystalline Phase Transition

[2]Pseudorotaxane [(FcCH2NH2CH2C6H4-4-Me)(DB24C8)][PF6] ([1][PF6]; Fc = ferrocenyl, DB24C8 = dibenzo[24]crown-8-ether) undergoes crystalline phase transition at 128 °C upon heating and at 106 °C upon cooling (α-phase at low temperature; β-phase at...

Stretching Induced Crystalline-Phase Transition in Energy-Conversion Poly(Vinylidene Fluoride) (PVDF) Films

2014 ◽  
Vol 1070-1072 ◽  
pp. 589-593
Author(s):  
Fei Peng Wang ◽  
Zheng Yong Huang ◽  
Jian Li
Keyword(s):  
Phase Transition ◽  
Crystalline Phase ◽  
High Speed ◽  
Vinylidene Fluoride ◽  
X Ray Diffraction ◽  
X Ray ◽  
Β Phase ◽  
Α Phase ◽  
Poly Vinylidene Fluoride ◽  
Crystalline Phase Transition

Commercial poly (vinylidene fluoride) (PVDF) films are uniaxially stretched with varying rates at 110 °C in order to endow PVDF piezo-and pyroelectric by crystalline-phase transition from α to β during the stretching. The crystalline phases are determined by infrared spectroscopy. The β-phase content and its fraction in films increase as a result of stretching with high rates. In addition, higher stretching rates yield a slight increase of γ phase. The crystallite size is evaluated by means of X-ray diffraction. It is found that the β-phase crystallites become smaller with fast stretching, whereas the α-phase crystallites are cracked and disappear at high-speed stretching of 2.5 /min.

scholarly journals Phase transition and structures of the twinned low-temperature phases of (Et4N)[ReS4]

2020 ◽  
Vol 76 (3) ◽  
pp. 231-235
Author(s):  
Eduard Bernhardt ◽  
Regine Herbst-Irmer
Keyword(s):  
Phase Transition ◽  
Low Temperature ◽  
Title Compound ◽  
Room Temperature ◽  
Monoclinic Space Group ◽  
Rapid Cooling ◽  
Space Group ◽  
Disordered Structure ◽  
Β Phase ◽  
Α Phase

The title compound, tetraethylammonium tetrathiorhenate, [(C2H5)4N][ReS4], has, at room temperature, a disordered structure in the space group P63 mc (Z = 2, α-phase). A phase transition to the monoclinic space group P21 (Z = 2, γ-phase) at 285 K leads to a pseudo-merohedral twin. The high deviation from the hexagonal metric causes split reflections. However, the different orientations could not be separated, but were integrated using a large integration box. Rapid cooling to 110–170 K produces a metastable β-phase (P63, Z = 18) in addition to the γ-phase. All crystals of the β-phase are contaminated with the γ-phase. Additionally, the crystals of the β-phase are merohedrally twinned. In contrast to the α-phase, the β- and γ-phases do not show disorder.

Polymorphism of the quasiracemate d-2-aminobutyric acid:l-norvaline

CrystEngComm ◽  
2017 ◽  
Vol 19 (37) ◽  
pp. 5604-5610 ◽  
Author(s):  
M. M. H. Smets ◽  
E. Kalkman ◽  
P. Tinnemans ◽  
A. M. Krieger ◽  
H. Meekes ◽  
...  
Keyword(s):  
Phase Transition ◽  
Low Temperature ◽  
Single Crystal ◽  
Aminobutyric Acid ◽  
Crystal Phase ◽  
Thermal Microscopy ◽  
Temperature Form ◽  
Crystal Phase Transition

A new polymorphic quasiracemate d-2-aminobutyric acid:l-norvaline has been discovered and its reversible single-crystal-to-single-crystal phase transition has been studied using XRD, DSC and thermal microscopy. The low temperature form I is fully ordered, while form II shows two conformations for l-norvaline with a 50/50 occupancy.

Amorphous-to-crystalline phase transition of (InTe)x(GeTe) thin films

2010 ◽  
Vol 108 (2) ◽  
pp. 024506 ◽  
Author(s):  
Ki-Ho Song ◽  
Seung-Cheol Beak ◽  
Hyun-Yong Lee
Keyword(s):  
Thin Films ◽  
Phase Transition ◽  
Crystalline Phase ◽  
Crystalline Phase Transition

Improving dispersive mixing in compatibilized polystyrene/polyamide-6 blends via extension-dominated reactive single-screw extrusion

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Hao Chen ◽  
João M. Maia
Keyword(s):  
Phase Transition ◽  
Crystalline Phase ◽  
Reactive Extrusion ◽  
Polyamide 6 ◽  
Single Plane ◽  
Single Screw ◽  
Single Screw Extrusion ◽  
Double Plane ◽  
Dispersive Mixing ◽  
Crystalline Phase Transition

Abstract Extensional mixing elements (EMEs) that impose extension-dominated flow via stationary single-plane or double-plane hyperbolic converging-diverging channels were previously designed for twin-screw and single-screw extruders (TSE and SSE, respectively). In a recently published work by the authors, reactive extrusion was performed on PS/PA6 polymer blends TSE using EMEs and a crystalline phase transition of the minor phase in these droplets was observed as the size of droplet decreases from micron to submicron. Herein, we expand upon this work to SSE and study: a) The ability of the EMEs to improve dispersive mixing in the same blends; b) Assess the possibility of achieving the same crystalline phase transition in SSEs. The final blends were characterized by DSC, rheologically and morphologically via SEM, and the results show that while EME-based SSE leads to much improved mixing, better than non-EME TSE, the reduction in size of the PA6 disperse phase is not enough to induce the phase transition observed in EME-based TSE.

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