Please use this identifier to cite or link to this item: https://doi.org/10.1002/1099-0488(20001201)38:23<3018
Title: Double melting behavior of a liquid crystalline polyimide derived from PMDA and 1,3-bis[4-(4′-aminophenoxyl) cumyl] benzene
Authors: Liu, S.L. 
Chung, T.S. 
Oikawa, H.
Yamaguchi, A.
Issue Date: 1-Dec-2000
Source: Liu, S.L.,Chung, T.S.,Oikawa, H.,Yamaguchi, A. (2000-12-01). Double melting behavior of a liquid crystalline polyimide derived from PMDA and 1,3-bis[4-(4′-aminophenoxyl) cumyl] benzene. Journal of Polymer Science, Part B: Polymer Physics 38 (23) : 3018-3031. ScholarBank@NUS Repository. https://doi.org/10.1002/1099-0488(20001201)38:23<3018
Abstract: The double melting behavior of a thermotropic liquid crystalline polyimide was studied by means of differential scanning calorimetry (DSC), polarized light microscopy (PLM), transmission electron microscopy (TEM), wide-angle X-ray diffraction (WAXD), and small-angle X-ray scattering (SAXS). This liquid crystalline polyimide exhibited a normal melting peak around 278 °C and transformed into a smectic A phase. The smectic A phase changed to nematic phase upon heating to 298 °C, then became isotropic melt around 345 °C. The samples annealed or isothermally crystallized at lower temperature showed double melting endotherms during heating scan. The annealing-induced melting endotherm was highly dependent on annealing conditions, whereas the normal melting endotherm was almost not influenced by annealing when the annealing temperature was low. Various possibilities for the lower melting endotherm are discussed. The equilibrium melting points of both melting peaks were extrapolated to be 283.2 °C. Combined analytical results showed that the double melting peaks were from the melting of the two types of crystallites generated from two crystallization processes: a slow and a fast one. Fast crystallization may start from the well-aligned liquid crystal domains, whereas the slow one may be from the fringed or amorphous regions.
Source Title: Journal of Polymer Science, Part B: Polymer Physics
URI: http://scholarbank.nus.edu.sg/handle/10635/66531
ISSN: 08876266
DOI: 10.1002/1099-0488(20001201)38:23<3018
Appears in Collections:Staff Publications

Show full item record
Files in This Item:
There are no files associated with this item.

Page view(s)

37
checked on Dec 14, 2017

Google ScholarTM

Check

Altmetric


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.