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Home  >  Journal list  >  Polymer Journal  >  Vol.30  No.10 (1998)  >  pp.805-812

Polymer Journal
<<Previous article Vol.30  No.10 (1998)   pp.805 - 812 Next article>>

Absorption, Fluorescence, and Thermal Properties of Transparent Polyimides Based on Cyclobutanetetracarboxylic Dianhydride

Qinghua Li1), Kazuyuki Horie1) and Rikio Yokota2)
1) The University of Tokyo, Graduate School of Engineering, Department of Chemistry and Biotechnology
2) Institute of Space and Astronautical Science


ABSTRACT:  Ultraviolet/visible absorption spectra and fluorescence spectra of transparent polyimides derived from 1,2:3,4-cyclobutanetetracarboxylic dianhydride (CBDA) with an aromatic diamine, 4,4′-diaminodiphenylmethane (DPM), a fluorinated diamine, 2,2-bis(4-diaminodiphenyl)hexafluoropropane (6FdA), and an alicyclic diamine, 4,4′-diaminodicyclohexylmethane (DCHM) were investigated, compared with their model compounds. Both monomer and excimer fluorescence were observed in concentrated CH2Cl2 solution of model compounds, suggesting head to tail intermolecular overlap structures at the excited state. All polyimide films derived from CBDA showed high transparency in the visible region, i.e., no absorption tail was found above 375 nm. Especially, PI(CBDA/DCHM) showed the highest transparent property with almost no absorption above 310 nm. Absorption shoulders at 235 nm of PI(CBDA/DPM) and PI(CBDA/6FdA) are due to the absorption of phenylene groups in the diamine moieties. The fluorescence spectra of all polyimide films studied showed the existence of ground-state complexes. Their excitation wavelength dependence would be due to the existence of various conformations of packing structure. The glass transition temperatures, Tg, of these polyimides based on CBDA lie in the region of 277°C to 360°C. These polyimides have decomposition temperatures around 450°C under deaerated conditions.


Keyword:
Transparency/ Polyimides/ Alicyclic Dianhydride/ Fluorescence/ Excitation Wavelength Dependence/ Packing Structure/ Glass Transition Temperature

Published online: March 30, 2005
© Copyright, 2005 by The Society of Polymer Science, Japan

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