Polymers of carbonic acid, 5. Nematic polyurethanes derived from 4,4′‐dihydroxybiphenyl and 4,4′‐bipiperidine, ethylene‐4,4′‐bipiperidine or trimethylene‐4,4′‐bipiperidine

• Published in: Die Makromolekulare Chemie
• Main Authors: Kricheldorf, Hans R., Awe, Jens
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1989
• Subjects: Carbonic acid
• Online Access: http://dx.doi.org/10.1002/macp.1989.021901024; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fmacp.1989.021901024; https://onlinelibrary.wiley.com/doi/pdf/10.1002/macp.1989.021901024

Abstract 4,4′‐Bipiperidine ( 3a ), 1,2‐bis(4‐piperidinyl)ethane ( 3b ) and 1,3‐bis(4‐piperidinyl)propane ( 3c ) were condensed with the dichloroformates of p ‐phenylene, 2‐methyl‐1,4‐phenylene or 2,5‐biphenylylene. Furthermore, two copolyurethanes were prepared either by mixing 3a and 3c or by mixing the dichloroformates for p ‐phenylene and 2,5‐biphenylylene. Inherent viscosities between of 0,6 and 1,7 dl/g were found for the polyurethanes of 3c , but only values below 0,86 dl/g for those of 3a and 3b . The polyurethanes derived from hydroquinone or methylhydroquinone are semicrystalline polymers with a short‐term thermostability up to 310°C. The polyurethanes deriving from phenylhydroquinone are amorphous with a thermostability up to 360°C. The homo‐and copolyurethanes containing 4,4′‐biphenylylene units form a smectic layer structure in the solid state and a nematic melt above the melting point.