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Titre du document / Document title

Configuration effects of ortho, meta, and para linkages on liquid crystallinity during thin-film polymerization of poly(ester-amide)s

Auteur(s) / Author(s)

CHENG S.-X. (1 2) ; CHUNG T.-S. (1 2) ;

Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)

(1) Institute of Materials Research and Engineering, 3 Research Link, Singapore 117602, SINGAPOUR
(2) Department of Chemical and Environmental Engineering, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260, SINGAPOUR

Résumé / Abstract

By in situ thin-film polymerization conducted on a heating stage of a polarizing microscope, we have investigated the effects of monomer structures on the formation of liquid crystallinity. Three polymerization systems studied are 2,6-acetoxynaphthoic acid (ANA)/acetoxy acetanilide (AAA)/phthalic acid (PA), ANA/AAA/ isophthalic acid (IA) and ANA/AAA/terephthalic acid (TA). In the three systems, PA, IA, and TA may create an ortho, a meta, and a para linkage, respectively. The formation of liquid crystallinity was found strongly dependent on the straightness and configuration of monomeric units. For ANA/AAA/PA and ANA/AAA/IA systems, there exists the critical ANA content to yield the liquid crystalline phase. Below this critical content, either amorphous phase forms or crystallization occurs during polymerization. Experimental data also indicate that defect density in the polymerization product reduces with increasing ANA content. Surprisingly, for the first time, we have observed that the ANA/AAA/PA system has a higher tendency to yield liquid crystallinity than the ANA/AAA/IA system. For the ANA/AAA/TA system, the polycondensation reaction is incomplete if the TA content is too high because of the low reactivity and the high melting point of TA. Polymerization of the ANA/AAA/TA system does not yield totally random copolymers because the liquid crystal phase appears before all TA crystals disappear during the polymerization.

Revue / Journal Title

Journal of polymer science. Part B. Polymer physics    ISSN  0887-6266   CODEN JPLPAY 

Source / Source

2000, vol. 38, no17, pp. 2221-2231 (19 ref.)

Langue / Language

Anglais

Editeur / Publisher

Wiley, Hoboken, NJ, ETATS-UNIS  (1986) (Revue)

Mots-clés anglais / English Keywords

Esteramide copolymer

;

Aromatic copolymer

;

Liquid crystal polymers

;

Thermotropic state

;

Copolycondensation

;

Naphthalene derivatives

;

Morphology

;

Structure composition relationship

;

Structure effect

;

Position isomer

;

Comparative study

;

Experimental study

;

Mots-clés français / French Keywords

Esteramide copolymère

;

Copolymère aromatique

;

Polymère cristal liquide

;

Etat thermotrope

;

Copolycondensation

;

Naphtalène dérivé

;

Morphologie

;

Relation composition structure

;

Effet structure

;

Isomère position

;

Etude comparative

;

Etude expérimentale

;

Structure phase

;

Mots-clés espagnols / Spanish Keywords

Esteramida copolímero

;

Copolímero aromático

;

Estado termotropo

;

Copolicondensación

;

Naftaleno derivado

;

Morfología

;

Relación composición estructura

;

Efecto estructura

;

Isómero posición

;

Estudio comparativo

;

Estudio experimental

;

Localisation / Location

INIST-CNRS, Cote INIST : 6199 A2, 35400009095119.0020

Nº notice refdoc (ud4) : 1442522



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