Mesomorphic properties of liquid crystalline polysiloxanes and elastomers based on a tri-vinyl crosslinker

• Published in: Liquid crystals Vol. 30; no. 9; pp. 1015 - 1019
• Main Authors: Zhang, Bao-Yan, Liu, Lu-Mei, Feng, Zhi-Liu, Jia, Ying-Gang
• Format: Journal Article
• Language: English
• Published: Taylor & Francis Group 01.09.2003
• ISSN: 0267-8292; 1366-5855
• DOI: 10.1080/026782903100010721

A series of crosslinked liquid crystalline polymers and the corresponding uncrosslinked liquid crystalline polymers were prepared by graft copolymerization; their liquid crystalline properties were characterized by DSC, POM and X-ray measurements. The results show that the crosslinking obtained in the isotropic state leads to a reduction of the clearing point (T ) of the crosslinked polymers, as compared with the corresponding uncrosslinked polymers. The crosslinked polymers with low crosslinking density (P -P ) exhibit nematic mesogenic phases, as do the uncrosslinked polymers. In contrast, a high crosslinking density leads to the crosslinked polymers P and P losing their thermotropic liquid crystalline phases; they instead exhibit stress-induced orientation.