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| Titel: |
Preparation and Thermal Properties of Acetates Derived From Cellulose Dissolved in Dmso-Pf |
| Auteur: |
Miyagi, Yoshifumi Shiraishi, Nobuo Yokota, Tokuo Yamashita, Shigeko Hayashi, Yoshiyuki |
| Verschenen in: |
Journal of wood chemistry and technology |
| Paginering: | Jaargang 3 (1983) nr. 1 pagina's 59-78 |
| Jaar: |
1983 |
| Inhoud: |
Homogeneous acetylation of cellulose dissolved in the dimethyl sulfoxide(DMSO)/paraformaldehyde(PF) system was investigated. Characterization of the acetylated products was performed to evaluate the dissolution mechanism. The dissolution reactions are reasonably divided into three steps: (1)immediately after the dissolution, initial methylolation of cellulose; (2)further methylolation to form oligo-oxymethylene side chains on the cellulose backbone; (3)de-methylolation, that is, the break down of the side chain by prolonged heating. The possible methylolation reaction sites are all hydroxyls of the anhydrous glucose unit while the C-6 position is most reactive. Manipulation of the side chain lengths by control of the dissolution conditions makes it possible to prepare acetates with different thermal properties: Tg varied 35°-102.5°C and Tm 65° -122.5°C, depending upon the side chain length. Triethylamine(TEA) was prefered to pyridine, as a promotor of acetylation, in order to understand the dissolution mechanism. |
| Uitgever: |
Taylor & Francis |
| Bronbestand: |
Elektronische Wetenschappelijke Tijdschriften |
Details van artikel 7 van 8 gevonden artikelen
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