Carbonization of 3.5-dimethyl phenol-formaldehyde resin and its chemical structure at mesophase appearance
✍ Scribed by Y. Yamashita; K. Ouchi
- Publisher
- Elsevier Science
- Year
- 1979
- Tongue
- English
- Weight
- 518 KB
- Volume
- 17
- Category
- Article
- ISSN
- 0008-6223
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✦ Synopsis
The evolving gases during heat treatment of 3.5dimethyl phenol-formaldehyde resin up to looo"C were continuously analysed by means of gaschromatography, and the resin's structural change was investigated by using IR spectra. At 43o"C, a mosaic type mesophase suddenly appeared over the whole sample. Most of the sample carbonized at 400°C could be dissolved in pyridine, its chemical structure having been analysed by using NMR. Only 5.5 mol/MW of Hz0 and 1.5 mol/MW of CH, were evolved in the range of carbonization temperature up to 400°C, and the chemical structure at 400°C was nearly the same as that of original resin except for the formation of some methin and ether linkages with naphthene and heterocyclic rings; large aromatic condensed polycyclic structures have not developed yet at this point. At temperatures from 400 to 43o"C, only 0.52 mol/MW of HrO, 0.55 mol/MW of CH4 and 0.02 mol/MW of H2 evolved, showing that no severe structural change takes place. Thus, the mesophase formation in this resin does not necessitate the preexistence of large aromatic polycyclic structures, but is formed rather from planar large molecules.