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Titolo:
Melting behavior of a wholly aromatic liquid crystalline random copolyester
Autore:
Bensaad, S; Noel, C;
Indirizzi:
Ecole Super Phys & Chim Ind, Lab Physicochim Struct & Macromol, F-75231 Paris 05, France Ecole Super Phys & Chim Ind Paris France 05 ol, F-75231 Paris 05, France
Titolo Testata:
MACROMOLECULAR CHEMISTRY AND PHYSICS
fascicolo: 1, volume: 202, anno: 2001,
pagine: 36 - 50
SICI:
1022-1352(20010124)202:1<36:MBOAWA>2.0.ZU;2-S
Fonte:
ISI
Lingua:
ENG
Soggetto:
THERMOTROPIC COPOLYESTERS; MESOPHASE TRANSITIONS; RIGID-CHAIN; 3-DIMENSIONAL STRUCTURE; THERMAL TRANSITIONS; POLY(4-OXYBENZOATE-CO-1,4-PHENYLENE ISOPHTHALATE)S; RANDOM COPOLYMERS; POLYESTERS; KINETICS; POLYMER;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
43
Recensione:
Indirizzi per estratti:
Indirizzo: Noel, C Ecole Super Phys & Chim Ind, Lab Physicochim Struct & Macromol, 10Rue Vauquelin, F-75231 Paris 05, France Ecole Super Phys & Chim Ind 10 RueVauquelin Paris France 05 ance
Citazione:
S. Bensaad e C. Noel, "Melting behavior of a wholly aromatic liquid crystalline random copolyester", MACRO CH P, 202(1), 2001, pp. 36-50

Abstract

Differential scanning calorimetry and wide-angle X-ray diffraction studieswere carried out to investigate nonisothermal and isothermal crystallization of a thermotropic liquid crystalline copolyester consisting; of terephthalic acid (TA), p-hydroxybenzoic acid (HBA), 4,4'-oxydibenzoic acid (OBBA) and methylhydroquinone (MH) with mole ratios 19.2/23.1/19.2/38.5. Differentcrystallization processes are observed depending on crystallization conditions (cooling rate, crystallization temperature, crystallization time). Each of these processes is associated with a different melting point, heat of transition and kinetics of crystallization. The equilibrium thermodynamic properties of the process III (nonisothermal experiments at a cooling rate below 5 degreesC/min or isothermal experiments in the temperature region above ca. 260 degreesC) are found to be T-m(o) = 352 degreesC, DeltaH(o) = 10.4 kJ . mol(-1), and DeltaS degrees = 17 J . mol(-1) . K-1. This process is associated with (TA/OBBA-MH) sequences which, contain the "swivel" OBBA units.

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Documento generato il 03/04/20 alle ore 11:07:45