scholarly journals Phase transition behavior and deformation mechanism of polytetrafluoroethylene under stretching

RSC Advances ◽  
2021 ◽  
Vol 11 (63) ◽  
pp. 39813-39820
Author(s):  
Cong Luo ◽  
Jingke Pei ◽  
Wenyue Zhuo ◽  
Yanhua Niu ◽  
Guangxian Li
Keyword(s):  
Phase Transition ◽  
Differential Scanning Calorimetry ◽  
Small Angle ◽  
Deformation Mechanism ◽  
X Ray Diffraction ◽  
Phase Transition Behavior ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Transition Behavior ◽  
X Ray Scattering

The deformation mechanism and phase transition behavior of polytetrafluoroethylene (PTFE) under stretching conditions (25, 50, 100 °C) were investigated by using differential scanning calorimetry (DSC), small angle X-ray scattering (SAXS), and X-ray diffraction (XRD).

SAXS Study of Selected Cationic Surfactant Influence on the DSPC-Based Model Phospholipid System

2007 ◽  
Vol 130 ◽  
pp. 257-262
Author(s):  
Maciej Kozak ◽  
Ludwik Domka ◽  
Stefan Jurga
Keyword(s):  
Phase Transition ◽  
Differential Scanning Calorimetry ◽  
Small Angle ◽  
Phase Behaviour ◽  
Lamellar Phase ◽  
Scanning Calorimetry ◽  
X Ray ◽  
X Ray Scattering ◽  
Hydrocarbon Chains ◽  
Main Transition

The phase behaviour of lipid bilayer systems prepared with 1,2-distearoyl-sn-glycero-3- phosphocholine (DSPC) with dodecyldimethyl(benzyloxymethyl)ammonium chloride (BzMDDAC) (at concentrations 0.1, 1 and 5%) has been studied by small angle X-ray scattering and differential scanning calorimetry. The SAXS and DSC results of the hydrated 10% DSPC revealed one typical phase transition corresponding to melting of the hydrocarbon chains at 55 °C. In the system of 10% DSPC - 0.1 % BzMDDAC the main transition was somewhat shifted towards lower temperatures, while at 1% concentration of BzMDDAC in the mixture, the lamellar phase disappeared, as evidenced by SAXS and DSC. The increase in BzMDDAC concentration to 5% in the mixture with 10% DSPC resulted in formation of a new lamellar phase.

Heterocyclic and aromatic based polyurethane scaffolds: morphology and crystallinity studied by X-ray diffraction, small-angle X-ray scattering and differential scanning calorimetry

2013 ◽  
Vol 46 (4) ◽  
pp. 980-992 ◽  
Author(s):  
Tarek M. Madkour ◽  
Sahar K. Mohamed
Keyword(s):  
Thermal Stability ◽  
Differential Scanning Calorimetry ◽  
Small Angle ◽  
Aromatic Diamine ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
X Ray Scattering ◽  
Chain Extenders ◽  
Ray Scattering

The morphology, crystallinity and X-ray diffraction of speciality heterocyclic and aromatic based polyurethane and poly(urethane–urea) elastomers synthesized via a one-shot polymerization method were studied. The samples were chain extended by mixtures of aliphatic diols and furanic or aromatic diamine chain extenders. Small-angle X-ray scattering (SAXS) measurements confirmed the results obtained by differential scanning calorimetry (DSC) and revealed the presence of phases with sharp phase boundaries. The SAXS patterns are best fitted with a model that consists of liquid-like ordered polydisperse spheres. Most of the samples were shown to be poorly crystalline, but some soft-phase crystals do exist and these melted at about 353 K as confirmed by DSC and temperature-dependent wide-angle X-ray diffraction. Annealing at 273 K did not affect the thermal stability but influenced the morphology of the samples. The effect of annealing on the samples of poly(urethane–urea) extended using diamine chain extenders was smaller than that for polyurethane samples, which indicates a much higher thermal stability of the poly(urethane–urea) samples owing to the formation of bidentate hydrogen-bond networks across the urea groups.

Phase Transition Behavior of Main Chain Nematic Liquid-Crystalline Polymers Based on 2-methyl-1,4-bis[4-(4-pentenyloxy)benzoyl]hydroquinone and 2-tert-butyl-1,4-bis[4-(4-pentenyloxy)benzoyl]hydroquinone

2012 ◽  
Vol 1403 ◽  
Author(s):  
Christain Melchert ◽  
M. Behl ◽  
A. Lendlein
Keyword(s):  
Phase Transition ◽  
Nematic Phase ◽  
Liquid Crystalline ◽  
Liquid Crystalline Polymers ◽  
Phase Transition Behavior ◽  
Scanning Calorimetry ◽  
Thermal Stabilities ◽  
Crystalline Polymers ◽  
Transition Behavior ◽  
X Ray Scattering

ABSTRACTThe control of phase transition behavior in liquid crystalline polymers could enable potential application in the field of actuators and sensors by enabling a higher actuator performance of liquid crystalline elastomers (LCE). In this context the phase transition behavior of siloxane based liquid crystalline copolymers synthesized from 1,1,3,3-tetramethyldisiloxane, 2-methyl-1,4-bis[4-(4-pentenyloxy)benzoyl]hydroquinone (M-MeHq), and 2-tert-butyl-1,4-bis[4-(4-pentenyloxy)benzoyl]hydroquinone (M-tBHq) was explored. The selected monomers provided different thermal stabilities of the nematic phase, while the non-flexible siloxane spacer suppressed a smectic phase. The mesogenic properties were studied by means of differential scanning calorimetry (DSC), polarizing optical microscopy (POM), and wide angle X-ray scattering (WAXS). With increasing fraction of M-MeHq the nematic phase of the copolymer was stabilized and a tailoring of relatively low TNI was achieved.

Analysis of phase transition behavior of BaCeO3 with thermal analyses and high temperature X-ray diffraction

2009 ◽  
Vol 180 (17-19) ◽  
pp. 1034-1039 ◽  
Author(s):  
Takeshi Ohzeki ◽  
Shinya Hasegawa ◽  
Misa Shimizu ◽  
Takuya Hashimoto
Keyword(s):  
Phase Transition ◽  
High Temperature ◽  
Thermal Analyses ◽  
X Ray Diffraction ◽  
Phase Transition Behavior ◽  
X Ray ◽  
Transition Behavior
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