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Characterization of melt processable liquid crystal copolyesters.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Characterization of melt processable liquid crystal copolyesters./
Author:	Thammongkol, Vivan.
Published:	Ann Arbor : ProQuest Dissertations & Theses, : 1994,
Description:	285 p.
Notes:	Source: Dissertations Abstracts International, Volume: 56-10, Section: B.
Contained By:	Dissertations Abstracts International56-10B.
Subject:	Polymers. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=9517151
ISBN:	9798208974599

Characterization of melt processable liquid crystal copolyesters.
Thammongkol, Vivan.

Characterization of melt processable liquid crystal copolyesters. - Ann Arbor : ProQuest Dissertations & Theses, 1994 - 285 p.

Source: Dissertations Abstracts International, Volume: 56-10, Section: B.

Thesis (Ph.D.)--Georgia Institute of Technology, 1994.

This item must not be sold to any third party vendors.

All aromatic thermotropic polymers exhibit very high melting temperatures and are generally not melt processable. The melting temperatures of these thermotropic polyesters are still high for the conventional fiber processing. The purposes of this research are to: (1) Synthesize melt processable thermotropic copolyesters, which contain a semi-rigid spacer, cyclohexylenedimethylene, between mesogenic units, using solution and melt processes. Copolyesters were synthesized from substituted-hydroquinone, 1,4-cyclohexanedimethanol, and terephthaloyl chloride. (2) Form fibers from the melts of these copolyesters. (3) Characterize the properties of the copolyesters and fibers. Polymer and fiber characterizations include elemental analysis, spectroscopic analysis (FTIR, $\\sp1$H NMR, $\\sp $C NMR, COSY), hot stage polarized light microscopy (PLM), wide angle x-ray diffraction (WAXD), dilute solution viscometry, solubility testing, thermal analysis (DSC, TGA), scanning electron microscopy (SEM), and INSTRON tensile testing. Copolyesters I, II, and III were successfully synthesized using a solution process. These copolyesters exhibit melting temperatures in a convenient processable level for conventional fiber spinning which is below 300$\\sp\\circ$C. They exhibited reasonable processing windows and sufficient viscosities for fiber formation. Melt polymerization was not feasible in the synthesis of these copolyesters due to the incompatibility of the starting materials in the melt. Fibers were prepared from the melts of Copolyesters II and III. Compared to copolyester systems containing a "flexible spacer", i.e. methylene groups, these copolyester systems have provided fibers with at least 3-4 times higher mechanical properties. These copolyesters exhibit a fair chance to produce stronger fibers if they are melt spun. Heat-treated fibers with a moderate tenacity of about 1.5 GPa ($\\sim$13 g/den) could be achieved.

ISBN: 9798208974599Subjects--Topical Terms:

535398
Polymers.

Characterization of melt processable liquid crystal copolyesters.
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035 $a (MiAaPQ)AAI9517151
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100 1 $a Thammongkol, Vivan. $3 3686461
245 1 0 $a Characterization of melt processable liquid crystal copolyesters.
260 1 $a Ann Arbor : $b ProQuest Dissertations & Theses, $c 1994
300 $a 285 p.
500 $a Source: Dissertations Abstracts International, Volume: 56-10, Section: B.
500 $a Publisher info.: Dissertation/Thesis.
500 $a Advisor: Polk, Malcolm B.
502 $a Thesis (Ph.D.)--Georgia Institute of Technology, 1994.
506 $a This item must not be sold to any third party vendors.
506 $a This item must not be added to any third party search indexes.
520 $a All aromatic thermotropic polymers exhibit very high melting temperatures and are generally not melt processable. The melting temperatures of these thermotropic polyesters are still high for the conventional fiber processing. The purposes of this research are to: (1) Synthesize melt processable thermotropic copolyesters, which contain a semi-rigid spacer, cyclohexylenedimethylene, between mesogenic units, using solution and melt processes. Copolyesters were synthesized from substituted-hydroquinone, 1,4-cyclohexanedimethanol, and terephthaloyl chloride. (2) Form fibers from the melts of these copolyesters. (3) Characterize the properties of the copolyesters and fibers. Polymer and fiber characterizations include elemental analysis, spectroscopic analysis (FTIR, $\\sp1$H NMR, $\\sp $C NMR, COSY), hot stage polarized light microscopy (PLM), wide angle x-ray diffraction (WAXD), dilute solution viscometry, solubility testing, thermal analysis (DSC, TGA), scanning electron microscopy (SEM), and INSTRON tensile testing. Copolyesters I, II, and III were successfully synthesized using a solution process. These copolyesters exhibit melting temperatures in a convenient processable level for conventional fiber spinning which is below 300$\\sp\\circ$C. They exhibited reasonable processing windows and sufficient viscosities for fiber formation. Melt polymerization was not feasible in the synthesis of these copolyesters due to the incompatibility of the starting materials in the melt. Fibers were prepared from the melts of Copolyesters II and III. Compared to copolyester systems containing a "flexible spacer", i.e. methylene groups, these copolyester systems have provided fibers with at least 3-4 times higher mechanical properties. These copolyesters exhibit a fair chance to produce stronger fibers if they are melt spun. Heat-treated fibers with a moderate tenacity of about 1.5 GPa ($\\sim$13 g/den) could be achieved.
590 $a School code: 0078.
650 4 $a Polymers. $3 535398
650 4 $a Engineering. $3 586835
690 $a 0495
690 $a 0537
710 2 $a Georgia Institute of Technology. $3 696730
773 0 $t Dissertations Abstracts International $g 56-10B.
790 $a 0078
791 $a Ph.D.
792 $a 1994
793 $a English
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=9517151