Novel thermotropic esters-based polymers with broad nematic processing windows

Autor: H. Boerstoel, J. Bos, C. De Ruijter, Theo J. Dingemans
Rok vydání: 2008
Předmět:
Zdroj: Journal of Polymer Science Part A: Polymer Chemistry. 46:6565-6574
ISSN: 1099-0518
0887-624X
DOI: 10.1002/pola.22967
Popis: In this study, a new series of semiflexible liquid crystalline (LC) polyesters and poly(ester-amide)s were synthesized and characterized. Polymers based on 4-hydroxybenzoic acid (4-HBA), 6-hydroxy-2-naphthoic acid (HNA), suberic acid (SUA), and sebacic acid (SEA) were modified with hydroquinone (HQ) and different concentrations of 4-acetamidophenol (AP) to obtain a polyester and two poly(ester-amide)s, respectively. All polymers were successfully prepared using conventional melt-condensation techniques. The polymers were characterized by inherent viscosity measurements, SEC, hot-stage polarizing microscopy, DSC, and TGA. The mechanical behavior was investigated using DMTA and tensile testing. All linear polymers have Tgs in the range of 50–80 °C and melt between 120 and 150 °C. Our polymers display good thermooxidative stabilities (5% wt loss at ∼ 400 °C) and exhibit homogeneous nematic melt behavior over a wide temperature range (ΔN ∼ 250 °C). The liquid crystal phase was lost when high concentrations of nonlinear monomers such as 3-HBA (>27 mol %) and resorcinol (RC) (>23 mol %) were incorporated. The LC polyester based on 4-HBA/HNA/HQ/SUA/SEA could easily be processed into good quality films and fibers. The films display good mechanical properties (E′ ∼ 4 GPa) and high toughness, that is, ∼ 15% elongation at break, at room temperature. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6565–6574, 2008
Databáze: OpenAIRE
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