1. Hydrophobic 2,7-octadienyl ether-cellulose nanofibrils using butadiene sulfone as the dual reagent and medium
- Author
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Fukuda, J and Hsieh, YL
- Subjects
cellulose ,nanocellulose ,hydrophobic cnfs ,telomerization ,solution-state nmr ,synopsis ,Prevention ,Analytical Chemistry ,Environmental Science and Management ,Chemical Engineering - Abstract
This is the first proof of concept of generating hydrophobic nanocelluloses by facile one-pot solventless telomerization using butadiene sulfone (BDS) to serve the dual functions of 1,3-butadiene (BD) reagent and reaction medium. Optimal telomerization of BD at 6 equiv of 2,7-octadienyl ether (ODE) to amorphous cellulose anhydroglucose (AGU) at 110 °C, or 6ODE110, and then disintegration by shear force yielded ca. 27−41% hydrophobic DMSO, THF, and CHCl3 dispersible nanocelluloses in 3.7, 6.3, and 4.4 nm thickness, respectively. The surface ODE group was evidenced in methylene peaks at 2800−2980 cm−1 and C=C at 1640−1704 cm−1 by FTIR and in both cis and trans C2−C3 double-bond conformations at 700 and 956 cm−1, respectively, by FTIR-ATR. Solution-state 1H NMR elucidated the ODE structure (d6-DMSO; δ 1.47, 1.95, and 2.07 ppm and 4.86, 5.29, 5.61, 5.90, and 6.07 ppm for methylene and olefinic protons, respectively) along with cellulosic protons (δ 4.12, 3.08, 3.28, 3.40, 3.53, 3.19, and 3.93 ppm for H1, 2, 3, 4, 5, 6a, and 6b, respectively), indicating a 30% conversion of surface OH to ODE. ODE-CNFs exhibited far superior thermal stability with a Tmax of 332 °C, 67 °C higher than that of TEMPO-CNFs. Most impressively, 1% ODE-NCs effectively converted hydrophilic solid mica and porous cellulose paper to hydrophobic surfaces with outstanding 102 ± 1 and 94 ± 2° water contact angles, respectively.
- Published
- 2021