Polymers from multifunctional isocyanates, 11. Thermotropic copolyurethanes from triad diesterdiisocyanates

✍ Scribed by Werner Mormann; Saria Benadda; Martin Brahm

• Book ID: 102940343
• Publisher: John Wiley and Sons
• Year: 1995
• Tongue: English
• Weight: 769 KB
• Volume: 196
• Category: Article
• ISSN: 1022-1352
• DOI: 10.1002/macp.1995.021960210

✦ Synopsis

Abstract

Two series of hard‐segment type polyurethane copolymers from para‐linked triad and diad aromatic or cycloaliphatic diisocyanatoesters using aliphatic low‐molecular‐weight diols as chain extenders are described. The first series has been made from one diisocyanate and two different chain extenders, the second from two different diisocyanates and one chain extender. The influence of the copolymer composition on the thermal transitions has been studied. Crystalline and glassy polyurethanes can be made with a wide range of isotropization temperatures. Systematic variation of the mole fraction of either the isocyanates or the chain extenders gives clearing transitions between those of the two binary polymers. An almost linear relationship between clearing temperature and the composition was found for polymers prepared from two isocyanates. With two different chain extenders, isotropization temperatures deviate slightly from a linear relationship.