P. Tapaswi, Myeon-Cheon Choi, Keuk-Min Jeong
May 19, 2015
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0
Influential Citations
59
Citations
Journal
Macromolecules
Abstract
2,2′-Bis(thiophenyl)benzidine (BTPB) and 2,2′-bis(4-chlorothiophenyl)benzidine (BCTPB) were synthesized via a benzidine rearrangement reaction of the corresponding hydrazobenzene derivatives obtained after the reduction of (3-nitrophenyl)(phenyl)sulfane and (4-chlorophenyl)(3-nitrophenyl)sulfane, respectively. Transparent polyimides (PIs) with high refractive indices and small birefringences as well as good thermomechanical stabilities were synthesized by the conventional two-step thermal polycondensation of BTPB and BCTPB with five different dianhydrides in N-methyl-2-pyrrolidone. 3,3′,4,4′-Biphenyltetracarboxylic dianhydride (BPDA)/BCTPB PI, a fully aromatic and non-fluorinated PI, with a highly distorted noncoplanar conformation of the main chain was transparent and colorless with a transmittance of ∼83% and >88% at 450 nm and in the visible region, respectively. In addition, all six non-fluorinated sulfur-containing aromatic PIs exhibited high average refractive indices (1.7112–1.7339), and small bire...