Liquid-crystalline polymers of virtually uniform molecular weight

US5332520A · kind A · utility

Assignee

• BASF SE

Inventors

• Volker Bach · Neustadt, DE
• Karl-Heinz Etzbach · Bischofswerda, DE
• Karl Siemensmeyer · Bischofswerda, DE

Key dates

• Filing date: May 8, 1992
• Grant date: Jul 26, 1994
• Expiry date: May 8, 2012

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08F20/30
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

A liquid-crystalline polymer of virtually uniform molecular weight, obtainable by polymerizing identical or different monomers of the formula I ##STR1## where R is hydrogen, chlorine or methyl, PA1 A is a flexible, long-chain moiety which acts as a spacer, is a mesogenic moiety built up from at least two aromatic rings which are linked to one another in a linear or approximately linear manner, and PA1 C is an optically active, chiral moiety, in from 0.01 to 0.1 molar solution in an inert organic solvent in the presence of from 1 to 40 mol %, based on the monomers, of a free-radical initiator, at from 40.degree. to 60.degree. C. for from 100 to 140 hours, and subsequently isolating the polymerization product from the reaction mixture, and the use thereof for building up recording layers for laser-optical and electrical recording elements and for electrophotography and for building up liquid-crystalline display elements.