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Correlation between molecular structure, free volume, and physical properties of a wide range of main chain thermotropic liquid crystalline polymers
Author(s) -
Hsieh TsungTang,
Tiu Carlos,
Simon George P.
Publication year - 2001
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.2073
Subject(s) - thermotropic crystal , glass transition , materials science , polymer , volume (thermodynamics) , polycarbonate , thermodynamics , composite material , polymer chemistry , liquid crystalline , physics
Physical phenomena such as glass transition temperatures, melting points, and relaxational behavior have been determined for a wide range of thermotropic liquid crystalline polymers (TLCPs) and polycarbonate (PC). Damping intensities of rigid TLCPs during glass transition are greater than those of semirigid and semiflexible TLCPs. Positron annihilation lifetime spectroscopy was also employed to evaluate free volume parameters of polymers. In general, the positron annihilation lifetime spectroscopy (PALS) free volume parameters show that all TLCPs have much smaller, fewer free volume sites compared with PC. Correlations were found between PALS free volume parameters and glass transition temperature, dynamic mechanical damping strength, and bulk density where greater free volume parameters corresponded to higher glass transition temperatures, greater damping strength, and lower density. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2252–2267, 2001