Molecular origin of unusual physical and mechanical properties in novel phenolic materials based on benzoxazine chemistry
✍ Scribed by Supa Wirasate; Sujitra Dhumrongvaraporn; Douglas J. Allen; Hatsuo Ishida
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 186 KB
- Volume
- 70
- Category
- Article
- ISSN
- 0021-8995
No coin nor oath required. For personal study only.
✦ Synopsis
The effect of temperature on hydrogen bonding was investigated by measuring the integrated infrared absorbance of various hydrogen-bonding modes as a function of temperature. It was found that conformationally preferred hydrogenbonding modes maintain constant intensities over the wide temperature ranges studied for both polybenzoxazines and a novolac-type phenolic resin. In particular, the O---H---N hydrogen bond shows strong bonding that does not change over the temperature range. On the other hand, statistically distributed hydrogen bonding is more sensitive to the temperature change and its infrared intensities start decreasing around the -transition of polybenzoxazines. The unusual physical and mechanical properties of polybenzoxazines, including volumetric expansion upon polymerization, high moduli, and high glass transition temperatures, are explained based on the complex hydrogen bonding.