Benzoxazines derived from bisphenol-A, formaldehyde, and primary amines were characterized using 13 C solid-state NMR spectroscopy. The two 1,3benzoxazines studied in this work are 2,2Π-(3-methyl-4-dihydro-1,3,2-benzoxazine)propane, (B-m) and 2,2Π-(3-phenyl-4-dihydro-1,3,2-benzoxazine)propane (B-a).
A solid-state 13C nuclear magnetic resonance study of cured, unsaturated polyester resins
β Scribed by Karin Hietalahti; Andrew Root; Mikael Skrifvars; Franciska Sundholm
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 160 KB
- Volume
- 73
- Category
- Article
- ISSN
- 0021-8995
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β¦ Synopsis
The styrene sequence distributions and amount of reacted fumarate units in cured, unsaturated polyester resins were studied by solid-state 13 C nuclear magnetic resonance. Increasing the styrene content and molar ratio of styrene to the double bonds in the polyester chain increased the amount of diad and n-ad sequences and decreased the amount of monad sequences. At the same time, the amount of reacted fumarate units increased. The glass transition temperature was almost constant for resins with the same composition but different styrene contents. Changing the composition affected the glass transition temperature, which could not be detected for highly crosslinked resins. The mechanical properties were improved with increasing styrene content.
π SIMILAR VOLUMES
A difunctional 1,3-benzoxazine compound, 2,2Π-(3-phenyl-4-dihydro-1,3,2benzoxazine)propane (B-a), derived from bisphenol-A, 15 N-enriched aniline, and formaldehyde was synthesized and characterized using 15 N-NMR and 13 C-NMR spectroscopies. The observed resonances in the solid-state 15 N-and 13 C-N