Title:Study on Acidic Degradation of Cellulose
Volume: 7
Issue: 1
Author(s): Michael Ioelovich*
Affiliation:
- Designer Energy Ltd. 2 Bergman Str., Rehovot 7670504,Israel
Keywords:
Cellulose, acid, corrosion, microcrystalline particles, nanocrystalline particles, degree of polymerization, degree of
crystallinity.
Abstract: Background: Acid hydrolysis is a common process used for the production of microcrystalline
and nanocrystalline cellulose. When the starting cellulose feedstock is treated with dilute mineral
acid (2-3 M), a sharp decrease in degree of polymerization (DP) is observed until a minimum constant
value called level-off degree of polymerization (DPm) is achieved, which is associated with DP of elementary
nanocrystallites. After such chemical treatment, despite achieving Pm, the particles of microcrystalline
cellulose (MCC) are formed instead of cellulose nanocrystallites (CNCs), which require further
explanation.
Methods: Observation of DP, crystallinity degree, particle size and charge depending on the acid concentration
and type.
Results: It was found that dilute acid causes a selective degradation of non-crystalline domains (NCD),
which leads to transverse splitting of relatively long fibers and obtaining of shorter low-molecular fragments
of the fibers, namely micron-size particles of MCC. On the other hand, concentrated acid causes
not only the degradation of NCD, but also tightly packed lateral surfaces between nanocrystallites connected
via strong inter-crystalline contacts, thus facilitating the release of free CNCs.
