Synthesis and property of 9,9′-spirobifluorene-containing aromatic polyesters as optical polymers with high refractive index and low birefringence
✍ Scribed by Ryota Seto; Takahiro Kojima; Katsumoto Hosokawa; Yasuhito Koyama; Gen-ichi Konishi; Toshikazu Takata
- Publisher
- Elsevier Science
- Year
- 2010
- Tongue
- English
- Weight
- 442 KB
- Volume
- 51
- Category
- Article
- ISSN
- 0032-3861
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✦ Synopsis
C 2 -Symmetric 9,9 0 -spirobifluorene-containing polyesters (PEs) were synthesized by polycondensation of 2,2 0 -dihydroxy-9,9 0 -spirobifluorene (1) with bis(acyl chloride)s (2) at 230 C in diphenylether. The molecular weights of PEs 3ae3f were sufficiently high (M w 13,400e41,600). PEs displayed high thermal stability. The glass transition temperatures (T g ) estimated by differential scanning calorimetry analysis appeared in a range 177e352 C depending on the spacer structure, while the 5% decomposition temperatures (T d5 ) measured by thermogravimetric analysis were over 416 C both under nitrogen atmosphere and in air. PEs showed good solubility in typical organic solvents such as CHCl 3 and THF easily to afford the tough, transparent, and flexible cast films. The transmittance of the polymer films reached over 90% in the wavelength range from ca. 410e900 nm. In addition, PEs exhibited higher refractive index rather than that of commercially available 9,9-diarylfluorene-containing PE, in addition to very low degree of birefringence presumably due to the C 2 -symmetric structure.