Improved resistance of chemically-modified nanocellulose against thermally-induced depolymerization.
The study demonstrated the improvement in the resistance of nanocellulose against thermally-induced depolymerization by esterification with benzoyl (BNZ) and pivaloyl (PIV). The change in the degree of polymerization (DP) and molecular weight distribution (MWD) after thermal treatment in nitrogen and in air was investigated using viscometry and gel permeation chromatography. BNZ and PIV nanocellulose esters without α-hydrogens gave higher DP and narrower MWD than pure bacterial cellulose; and the acetyl and myristoyl esters, which possess α-hydrogens. Results also showed that when depolymerization is suppressed, thermal discoloration is also reduced. Resistance against depolymerization inhibits the formation of reducing ends which can be active sites for thermal discoloration. Finally, the findings suggest that benzoylation and pivaloylation can be an excellent modification technique to improve the thermal stability of nanocellulose.
Research Institute for Sustainable Humanosphere, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan. Electronic address: agustin.melissa.78a@st.kyoto-u.ac.jp.
Melissa B
MB
Agustin
Research Institute for Sustainable Humanosphere, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan.
Fumiaki
F
Nakatsubo
Research Institute for Sustainable Humanosphere, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan.
Hiroyuki
H
Yano
Acetyl chloride (PubChem CID: 8481); Bacterial cellulose esters; Benzoyl chloride (PubChem CID: 7412); Molecular weight distribution; Myristoyl chloride (PubChem CID: 66986); Pivaloyl chloride (PubChem CID: 62493); Thermally-induced depolymerization; α-hydrogen