Studies on the thermotropic liquid crystalline polycarbonates—V. Synthesis and properties of carbonato side chain liquid crystalline polysiloxanes

✍ Scribed by Sun Shih-Jieh; Cheng Hsin-Pei; Chang Teh-Chou; Chang Chih-Huey

• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 603 KB
• Volume: 31
• Category: Article
• ISSN: 0014-3057
• DOI: 10.1016/0014-3057(95)00030-5

✦ Synopsis

Two series of spacer-containing carbonato side chain liquid crystalline polysiloxanes were prepared by hydrosilylation of various novel ally1 carbonates with poly(hydrogen-methylsiloxane). The thermotropic liquid crystalline properties of synthesized monomers and polymers were investigated by: (1) examination of the melt birefringence and stirred opalescene by a polarizing microscope equipped with a heating stage; (2) characterization of mesophase transitions by a differential scanning calorimeter (DSC); and (3) analysis of dielectric properties, conductivity and phase transition by a dielectric analyzer (DEA). It was found that most of the synthesized polymers with the carbonate groups in the side chains showed excellent mesophase stabilities and low glass transition temperatures. In the meantime, the melting transitions were reduced by introducing longer spacers.