Patent Title: DIPOLE-MODIFIED POLYURETHANE, METHOD FOR PRODUCING SAME, AND USE THEREOF IN THE PRODUCTION OF CAST ELECTROACTIVE POLYURETHANE-BASED ELASTOMER FILMS

 Number/Link: WO2016102320  (German)

Applicant/Assignee: Covestro

Publication date: 30-06-2016

“Gist”: A molecule with high dipole moment is incorparted in the PU backbone

Why it is interesting: According to this invention a polyurethane with an increased dielectric constant can be prepared by first reacting an isocyanate (f>2)with a hydroxyl-functional dipole.  This ‘dipole-modified’ isocyanate is then used in a (preferred) amount of 5-10% on the rest of the isocyanate of an elastomer formulation.  The dipole is of the form HO-R-D-X-A, where  D is an electron donor, A is an electron acceptor and X is a residue with a delocalized electron system.  In an example N-2-hydroxyethyl-N-methyl-4-nitroanilin is reacted with a biuret based on HDI to make the ‘dipole-modified’ isocyanate. Polyurethane elastomer films with high dielectric constant can be used as electromechanical transducers in sensors, actuators, artifical muscle etc..

N-2-Hydroxyethyl-N-Methyl-4-Nitroanilin

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