Abstract
Hygroscopic nature of cellulose is one of the most
difficult limiting factors to overcome in utilization of
nanocellulose. When unmodified nanocellulose structure is
subjected to humidity or immersed in water it loses its
structural integrity very quickly. Nanoscaled cellulose
fibrils form very tightly packed films, which can be
used, for example, as excellent barriers or membranes.
Water stability of nanocellulose films has been improved
by prepn. of multilayered structures, redn. of free vol.,
surface modification and additives. Polyvinyl alc. (PVA)
can be used to significantly enhance water stability of
films prepd. from TEMPO oxidized cellulose nanofibrils
(TOCNs). In water swollen TOCN films, PVA has two
functions; it can either improve the wet strength by
forming interfibrillar bridges or act as a plasticizer.
The interfibrillar bridging is result of two mechanisms:
1) hemiacetal bonding between PVA hydroxyls and aldehydes
in TOCNs and 2) acid catalyzed formation of ester bonds
between PVA hydroxyls and carboxylic groups in TOCNs.
Sufficient bonding between TOCNs to achieve water
stability could not be obsd. Mech. properties of the
films can be tuned without losing the water stability
merely by changing the amt. of PVA. Even after being
immersed in water for several months, TOCN/PVA films
maintain their structural integrity. The water stability
increases to such extent that TOCN/PVA films can be used
as water filtration membranes.
| Original language | English |
|---|---|
| Title of host publication | Abstracts of papers |
| Publisher | American Chemical Society ACS |
| Pages | CELL-203 |
| Publication status | Published - 2015 |
| Event | 249th ACS National Meeting and Exposition - Denver, United States Duration: 22 Mar 2015 → 26 Mar 2015 |
Seminar
| Seminar | 249th ACS National Meeting and Exposition |
|---|---|
| Country/Territory | United States |
| City | Denver |
| Period | 22/03/15 → 26/03/15 |