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Experimental and theoretical estimations of surface tensions for commercial liquid crystalline polymers, Vectra™ A‐950, B‐950 and Xydar™ SRT‐900
Author(s) -
Chung TaiShung,
Ma Kui Xiang,
Jaffe Mike
Publication year - 1998
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/(sici)1521-3935(19980601)199:6<1013::aid-macp1013>3.0.co;2-4
Subject(s) - contact angle , van der waals force , polymer , polymer chemistry , amide , base (topology) , naphthalene , surface energy , materials science , covalent bond , thermodynamics , chemistry , molecule , organic chemistry , composite material , physics , mathematical analysis , mathematics
By using the Lifshitz‐Van der Waals‐Acid‐Base theory, we have determined the surface tensions (γ s ) of three commercially available liquid crystalline polymers (LCPs) from the measurement of contact angles on thin films. The values obtained are 43.1, 41.1 and 41.5 mJ/m 2 (dyn/cm) for Vectra™ A‐950, Vectra™ B‐950 and Xydar™ SRT‐900, respectively. Experimental data suggest that all the three LCPs are monopolar. The strength of Lewis base (tendency to donate a pair of electrons for the formation of a covalent bond) for these three LCPs is as follows: Vectra™ B‐950 > Xydar™ SRT‐900 > Vectra™ A‐950. We also theoretically estimated γ s from both parachor ( P s ) and cohesive energy ( E coh ) utilizing the concept of molecular group contribution. It was found that γ s 's calculated from Hoftyzer & Van Krevelen and Hayes' E coh values are close to our experimental results obtained from contact angle measurements. This is especially true for Xydar™ SRT‐900 LCP, where γ s obtained from contact angle measurements is 41.5 mJ/m 2 , while from Hoftyzer and Van Krevelen, and Hayes it is 42.4 and 41.8 mJ/m 2 , respectively. However, more adequate group contributions for naphthalene and amide groups are urgently needed.