Liquid Crystal Polymers. IV. Liquid Crystalline Aromatic Polyesters

✍ Scribed by Jackson, W. Jerome

• Publisher: Wiley (John Wiley & Sons)
• Year: 2007
• Tongue: English
• Weight: 885 KB
• Volume: 12
• Category: Article
• ISSN: 0007-1641
• DOI: 10.1002/pi.4980120405

✦ Synopsis

Abstract

Melt‐spun and injection‐moulded liquid crystalline polyesters have very high strength and stiffness and a very low coefficient of linear thermal expansion. The exceptional properties that characterise these polyesters are due to the presence of stiff, rod‐like polymeric chains, which become highly oriented during melt‐spinning or injection‐moulding, and long relaxation times, which permit the chains to retain their orientation while the polymer is cooling. The introduction of either flexible aliphatic groups or kinks in the rod‐like polymer chains reduces the polyester melting points and thereby permits easier melt processing but also adversely affects the strength and stiffness properties which are obtained. The effects of composition on the melting point and properties of plastics and fibres of liquid crystalline aromatic polyesters is discussed.