new approach for controlling birefringent property of cyclic olefin copolymers

• Published in: Journal of polymer science. Part A, Polymer chemistry Polymer chemistry, 2008-11, Vol.46 (22), p.7395-7400
• Main Authors: Ban, Hoang The, Hagihara, Hideaki, Nishii, Kei, Tsunogae, Yasuo, Nojima, Shuichi, Shiono, Takeshi
• Format: Article
• Language: English
• Subjects: Applied sciences; birefringent control; catalysts; copolymerization; cyclic olefin copolymer; Electrical, magnetic and optical properties; ethylene; Exact sciences and technology; norbornene; Organic polymers; Physicochemistry of polymers; Properties and characterization; styrene
• ISSN: 0887-624X; 1099-0518
• DOI: 10.1002/pola.23044

This article reports an original method to control the birefringent property of the cyclic olefin copolymer, which has been recently commercialized as a new type of optical resins, via introduction of a third monomer that possesses a negative birefringence into the cyclic olefin copolymer that exhibits an inherently positive birefringence. The mutual compensation between these opposite-sign birefringences effectively reduced the birefringent magnitude of the corresponding terpolymer. In fact, terpolymerization of norbornene (N), ethylene (E), and styrene (S), in which S exhibits a negative birefringence regarding to the positive birefringence of the NE copolymer was successfully prepared using fluorenylamidodimethyltitanium-based catalyst, yielding NES terpolymers with controllable birefringent property. Especially, when the S content in the NES terpolymer was controlled at optimum values, it is possible to synthesize a new type of the cyclic olefin copolymer that exhibits an extremely low birefringent magnitude close to zero regardless of high degrees of chain orientation.