Thermotropic liquid crystalline copolyesters. II. Synthesis and thermal characterization of copolyesters of terephthalic acid, methyl hydroquinone and 1,4-butane diol

1991 ◽  
Vol 24 (4) ◽  
pp. 229-233
Author(s):  
Asoke K. Rath ◽  
Leena Selvaraj ◽  
Surendra Ponrathnam
Keyword(s):  
Terephthalic Acid ◽  
Liquid Crystalline ◽  
Thermal Characterization ◽  
Acid Methyl ◽  
Butane Diol

scholarly journals Characterization of New H-Bonded Liquid Crystalline Complexes Based on Iminophenyl Nicotinate

Crystals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 499 ◽  
Author(s):  
Rua B. Alnoman ◽  
Mohamed Hagar ◽  
Hoda A. Ahmed ◽  
Khulood A. Abu Al-Ola ◽  
Magdi M. Naoum ◽  
...  
Keyword(s):  
Terephthalic Acid ◽  
Density Functional ◽  
Liquid Crystalline ◽  
Uv Spectroscopy ◽  
Isophthalic Acid ◽  
Geometrical Parameters ◽  
Scanning Calorimetry ◽  
Acid Complex ◽  
Smectic A

Two new 1:2 supramolecular H-bonded liquid crystalline complexes (SMHBCs) were prepared through double H-bond interactions between either isophthalic acid (A) or terephthalic acid (B) and a nicotinate Schiff base (I6). The formed complexes were thermally investigated by differential scanning calorimetry (DSC), and their phases were identified by polarized optical microscopy (POM) and UV-spectroscopy. The formation of 1:2 hydrogen-bonded complexes was confirmed through their Fermi-bands observed by FT-IR spectroscopy. The first system (I6/A) was found to possess enantiotropic smectic A and nematic mesophases. Induced broad range of smectic A phase was observed in I6/A complex which is not shown by their individual components. The second complex system (I6/B) was purely nematogenic. Density functional theory (DFT) calculations were applied to predict their geometrical parameters. Theoretical studies revealed that the isophthalic complex adopted the W-shape; while the U-shape was adopted by the terephthalic acid complex (I6/B). The linear geometry of the complex based on the isophthalic acid enhanced the mesomorphic behavior observed by the terephthalic complex; I6/B. Actually; the orientation of the two carboxylic groups was shown to highly affect the softness of the derived complex. On the other hand; the mapping orientation of the charge distribution can be used to explain the mesophase behavior. The photophysical characterization of isophthalic complex (I6/A) is also discussed

Thermal Characterization of Liquid Crystalline Materials

2010 ◽  
Vol 98 (7) ◽  
pp. 429-438 ◽  
Author(s):  
P. van Ende ◽  
G. Groeninckx ◽  
H. Reynaers ◽  
K. U. Leuven
Keyword(s):  
Liquid Crystalline ◽  
Thermal Characterization ◽  
Crystalline Materials ◽  
Liquid Crystalline Materials

Random pseudo promptings applied to the thermal characterization of a wet porous material

1999 ◽  
Vol 6 (1) ◽  
pp. 101-108 ◽  
Author(s):  
E. Delacre ◽  
D. Defer ◽  
E. Antczak ◽  
B. Duthoit
Keyword(s):  
Porous Material ◽  
Thermal Characterization

Photoacoustic thermal characterization of the dehydration process of Agar-SiO2emulsions

2005 ◽  
Vol 125 ◽  
pp. 177-180
Author(s):  
T. Lopez ◽  
M. Picquart ◽  
G. Aguirre ◽  
Y. Freile ◽  
D. H. Aguilar ◽  
...  
Keyword(s):  
Thermal Characterization ◽  
Dehydration Process
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