scholarly journals Biobased Thermoplastic Elastomers: Structure-Property Relationship of Poly(hexamethylene 2,5-furanodicarboxylate)-Block-Poly(tetrahydrofuran) Copolymers Prepared by Melt Polycondensation

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 397
Author(s):  
Sandra Paszkiewicz ◽  
Izabela Irska ◽  
Agata Zubkiewicz ◽  
Anna Szymczyk ◽  
Elżbieta Piesowicz ◽  
...  
Keyword(s):  
Phase Transition ◽  
Shape Memory Polymer ◽  
Tensile Tests ◽  
Thermoplastic Elastomers ◽  
Sem Analysis ◽  
Transition Temperatures ◽  
Structure Property ◽  
Scanning Calorimetry ◽  
Molecular Weights ◽  
Phase Transition Temperatures

A series of poly(hexamethylene 2,5-furanodicarboxylate)-block-poly(tetrahydrofuran) (PHF-b-F-pTHF) copolymers were synthesized using a two-stage procedure, employing transesterification and polycondensation. The content of pTHF flexible segments varied from 25 to 75 wt.%. 1H nuclear magnetic resonance (NMR) and Fourier transformed infrared spectroscopy (FTIR) analyses were applied to confirm the molecular structure of the materials. Differential scanning calorimetry (DSC), dynamic mechanical measurements (DMTA), and X-ray diffraction (XRD) allowed characterizing the supramolecular structure of the synthesized copolymers. SEM analysis was applied to show the differences in the block copolymers’ morphologies concerning their chemical structure. The influence of the number of flexible segments in the copolymers on the phase transition temperatures, thermal properties, as well as the thermo-oxidative and thermal stability was analyzed. TGA analysis, along with tensile tests (static and cyclic), confirmed the utilitarian performance of the synthesized bio-based materials. It was found that an increase in the amount of pTHF caused the increase of both number-average and weight-average molecular weights and intrinsic viscosities, and at the same time causing the shift of the values of phase transition temperatures toward lower ones. Besides, PHF-b-F-pTHF containing 75 wt.% of F-pTHF units was proved to be a promising thermoplastic shape memory polymer (SMP) with a switching temperature of 20 °C.

scholarly journals Image Analysis Studies for Phase Transitions of Ferroelectric Liquid Crystals

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
S. Sreehari Sastry ◽  
B. Gowri Sankara Rao ◽  
K. B. Mahalakshmi ◽  
K. Mallika ◽  
C. Nageswara Rao ◽  
...  
Keyword(s):  
Phase Transition ◽  
Image Analysis ◽  
Liquid Crystals ◽  
Optical Microscope ◽  
Transition Temperatures ◽  
Scanning Calorimetry ◽  
Statistical Parameters ◽  
Ferroelectric Liquid Crystals ◽  
Phase Transition Temperatures ◽  
Parameter Values

Phase transition temperatures of ferroelectric liquid crystals ((S)-(-)-2-methylbutyl 4′-(4″-n-alkanoyloxybenzoyloxy) biphenyl-4-carboxylates (where n=16 and 18)) are studied through two techniques of image analysis. One is a statistical method, applied to compute the statistical parameters from the textures of each sample and the other, computation of Legendre moments being applied as image moment analysis, both of which are considered as a function of temperature. The textures of the samples are recorded with the polarizing optical microscope (POM) attached to the hot stage and high resolution camera. The phase transition temperatures of samples are inferred by the abrupt changes in the computed parameter values. The results obtained from the present methodology are in good agreement with those published in earlier literature done by the different techniques, like differential scanning calorimetry (DSC).

scholarly journals On the Thermal Behaviour of the n·C13-n·C20 Lithium Soaps

1980 ◽  
Vol 35 (1) ◽  
pp. 98-102 ◽  
Author(s):  
P. Franzosini ◽  
M. Sanesi ◽  
A. Cingolani ◽  
P. Ferloni
Keyword(s):  
Phase Transition ◽  
Differential Scanning Calorimetry ◽  
Thermal Behaviour ◽  
Room Temperature ◽  
Liquid Region ◽  
Transition Temperatures ◽  
Scanning Calorimetry ◽  
Isotropic Liquid ◽  
Phase Transition Temperatures

Abstract The phase transition temperatures and enthalpies were determined by differential scanning calorimetry between room temperature and the isotropic liquid region for the lithium n.alkanoates from tridecanoate to eicosanoate. The number and nature of the phases involved were discussed in comparison with the literature data available for some of the homologues concerned. For diffe-rent kinds of transitions, the significant features of the plots AS vs. number of carbon atoms were put into evidence.

scholarly journals Thermal, ferroelastic, and structural properties near phase transitions of organic–inorganic perovskite type [NH3(CH2)3NH3]CdBr4 crystals

RSC Advances ◽  
2021 ◽  
Vol 11 (29) ◽  
pp. 17622-17629
Author(s):  
Ae Ran Lim
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Thermal Behavior ◽  
Structural Properties ◽  
Structural Dynamics ◽  
Transition Temperatures ◽  
Inorganic Perovskite ◽  
Phase Transition Temperatures ◽  
Perovskite Type

We studied the thermal behavior and structural dynamics of [NH3(CH2)3NH3]CdBr4 near phase transition temperatures.

Triply-responsive OEG-based microgels and hydrogels: Regulation of swelling ratio, volume phase transition temperatures and mechanical properties

2021 ◽  
Author(s):  
Dongdong Lu ◽  
Mingning Zhu ◽  
Jing Jin ◽  
Brian R. Saunders
Keyword(s):  
Phase Transition ◽  
Biomedical Engineering ◽  
Volume Phase Transition ◽  
Swelling Ratio ◽  
Transition Temperatures ◽  
Ph Responsive ◽  
Network Systems ◽  
Volume Phase ◽  
Phase Transition Temperatures ◽  
Volume Swelling

Thermally- and pH-responsive microgels (MGs) and hydrogels are fascinating network systems that have been applied in biomedical engineering and sensing. The volume-swelling ratio (Q) and the volume-phase transition temperatures (VPTTs)...

scholarly journals Investigating phase transition temperatures of size separated gadolinium silicide magnetic nanoparticles

AIP Advances ◽  
2018 ◽  
Vol 8 (5) ◽  
pp. 056428 ◽  
Author(s):  
Shivakumar G. Hunagund ◽  
Shane M. Harstad ◽  
Ahmed A. El-Gendy ◽  
Shalabh Gupta ◽  
Vitalij K. Pecharsky ◽  
...  
Keyword(s):  
Phase Transition ◽  
Magnetic Nanoparticles ◽  
Transition Temperatures ◽  
Phase Transition Temperatures

Isotope effect on displacive-type ferroelectric-phase-transition temperatures

1990 ◽  
Vol 41 (13) ◽  
pp. 9581-9584 ◽  
Author(s):  
A. Bussmann-Holder ◽  
H. Büttner
Keyword(s):  
Phase Transition ◽  
Isotope Effect ◽  
Ferroelectric Phase Transition ◽  
Ferroelectric Phase ◽  
Transition Temperatures ◽  
Phase Transition Temperatures ◽  
Displacive Type
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