Poly(vinylspirobifluorene): Synthesis and Properties of a Novel Styrenic Polymer

Abstract

Synthesis and properties of a new class of styrenic polymer are reported. The radical polymerization of 2-vinyl-9,9 0 -spirobifluorene yielded high molecular weight poly(vinylspirobifluorene) with high thermal stability and high solubility, which gave a self-standing transparent film with high refractive index.Polymers containing 9,9-diarylfluorene (DAF) moieties, so called ''cardo'' structure, in the main chains are an intriguing class of polymers owing to their attractive nature. The ''cardo'' polymers have recently generated particular interest due to their characteristic properties such as high refractive index, 1 low birefringence, 1 high solubility, high thermal stability, and fine dispersing ability toward fillers.2 Meanwhile, 9,9 0 -spirobifluorene (2) (SBF) is a spirocyclic derivative of 9,9-diphenylfluorene (1), of which two phenyls are connected at their C2 0 and C2 00 positions through C-C bonds (Figure 1). The structure of 2 consisting of the vertically crossing fluorene moieties is expected to display both high refractive index and low birefringence by the high dense aromatics and cancellation of optical anisotropy like 1. Several studies directed toward optical use have been reported, 3 in which the spirocyclic structure enabled suppression of aggregation or excimer formation, leading to most promising blue-light emitting materials. We have also developed general entries to polycarbonate and polyesters possessing 9,9-spirobifluorene skeletons in the main chains. 4,5 It turns out that the resulting polymers contain the requisite moieties of defined hindrance to minimize interchromophore interaction. Among monomers having SBF skeletons in the side chains, vinyl monomer directly attached by the SBF moiety seems the most fundamental polymerizable derivative of 2. Herein, we report the synthesis and polymerization of 2-vinyl-9,9 0 -spirobifluorene and properties of the resulting polymer. A few typical optical properties such as transparency and refractive index are also evaluated in addition to the thermal properties.Synthesis of monomer 2-vinyl-9,9 0 -spirobifluorene (4) from 2-bromo-9,9 0 -spirobifluorene (3) 6 was achieved by Stille coupling exploiting tributylvinylstannane in the presence of Pd(PPh 3 ) 4 (5 mol %) as the catalyst (91% yield).

Spiro-Fluorene-Containing Cyclic Olefin Polymers

“…They are potential candidates for optical lens components with small Abbe numbers. , Compared with condensation polymers, fluorene-containing hydrocarbon polymers are rather limited. Several examples include π-stacked poly­(dibenzofulvene)­s by the radical polymerization, , a poly­(9,9-diallylfluorene) by the Ni-catalyzed cyclopolymerization, polystyrenes bearing fluorene moieties by the living anionic polymerization, poly­(vinylspirobifluorene) by the radical polymerization, and cyclic olefin copolymers by the Ti-catalyzed addition copolymerization of norbornene (NB) with a fluorene-containing α-olefin, showing lower photoelasticity dependent on the incorporation ratio of the α-olefin . These hydrocarbon polymers are expected to be superior to the condensation polymers in terms of low hygroscopicity and excellent chemical and dimensional stability under harsh and humid conditions.…”

Synthesis of colorless and high-refractive-index sulfoxide-containing polymers by the oxidation of poly(phenylene sulfide) derivatives

“…Takata and coworkers reported highly soluble and transparent polymers composed of 9,9′-diarylfluorene (DAF), known as a cardo structure with orthogonally arranged four aromatic rings. 19,20 The bulky and isotropic feature of DAF prevented the intra/intermolecular interactions between the polymer chains, leading to small birefringence and excellent transparency while possessing a high RI. 21 Moreover, introducing spirobifluorene (SBF), which is an analog of DAF with a spatially constrained C-C bond between the 2 and 2′-positions, was much more effective for obtaining higher RI, higher transparency, and smaller birefringence which were ascribed to a more compact and isotropic skeleton.…”

Synthesis and properties of pendant fluorene moiety-tethered aliphatic polycarbonates

“…Furthermore, some of them have good processability because of their appropriate glass transition and high decomposition temperatures, as well as good solubility in organic solvents. 1,2 We have long studied the synthesis and properties of many cardo polymers having 9,9-diarylfluorene moieties [3][4][5][6][7][8][9][10][11][12][13][14][15][16] and recently reported the preparation of cardo-like polymers [17][18][19][20][21] that have 9,9′-spirobifluorene moieties as the main chain units. Most cardo polymers hitherto studied have been aromatic, whereas aliphatic cardo polymers, 'cardo carbochain polymers' as defined by Korshak, 1 are also interesting because of their expected moderate properties based on their flexible main chains, although only a few reports dealing with fluorenecontaining polymers or oligomers have been reported so far, to the best of our knowledge.…”