The Benkeser reaction is a relatively simple method to proceed with partial reduction using ethylenediamine, lithium, and tert-butanol. Pyridine (N-6) and pyrrole (N-5) on the carbon skeleton are slightly negatively charged and not suitable for adsorption of nitrate ion (NO₃⁻). On the other hand, the amino group is positively charged by protonation and is considered to be excellent for adsorption of NO₃⁻. In this study, we attempted to prepare carbon fibers (CFs) with amino groups by performing the Benkeser reaction on the air-stabilized polyacrylonitrile (PAN)-based carbon fiber (PYROMEX). Various experiments and assesses were carried out on the optimized samples to investigate the adsorption performance of prepared CFs. Adsorption experiments of copper ion (Cu²⁺) were also conducted to confirm the presence of amino groups. The Benkeser reaction reduced the amounts of N-6 and N-5 on the carbon skeleton from 0.22 to 0.15 and from 10.36 to 7.35 wt%, respectively. On the other hand, the amino group value increased from 2.33 to 3.67 wt% and the protonated amino group value rose from 3.50 to 7.92 wt%. The surface areas (S_BET) of PYROMEX and Py-Ben-Bu60 were 9 and 8 m²/g, respectively, and there was not any development of pore structure at all. The maximum adsorption amount (X_m) of Py-Ben-Bu60 for the Langmuir isotherm model was 0.85 mmol/g at the equilibrium solution pH (pH_e) 3. These results indicated that the Benkeser reaction did not affect the pore properties such as S_BET, but was an effective method for reducing nitrogen functional groups on the carbon skeleton to amino groups and preparing CFs with high NO₃⁻ adsorption capacity. The Cu²⁺ adsorption amount of Py-Ben-Bu60 was 0.31 mmol/g at solution pH_e 5.19. Py-Ben-Bu60 was a favorable adsorbent for NO₃⁻ under acidic conditions and for Cu²⁺ under close to neutral conditions such as solution pH_e 5.

Polyfluorene (PF) and its derivatives have been widely recognized as PLED materials with several advantages. To fulfill higher electron transporting properties, we incorporated polystyrene (PSt) at the active position of fluorene as side chain. Polyfluorene-graft-polystyrene (PF-g-PSt) was prepared with a different ratio of PSt side chain in the PF main chain. Compared with various properties of the homopolymer, it is found that that the graft polymers had similar thermal and electrochemical performance, less the β-phase formation and photoluminescent stability, but smoother surface and higher crystallinity. Judging from the electron mobilities determined from the space charge limited current profiles, it was found that the graft polymer with one PSt side chain in main chain in average exhibited the higher electron mobility than the homopolymer and other graft polymers attached with more PSt side chains.