posted on 2014-03-10, 00:00authored byToon J. Bosmans, Agnes M. Stépán, Guillermo Toriz, Scott Renneckar, Erdem Karabulut, Lars Wågberg, Paul Gatenholm
This study focused on the assembly
characteristics of debranched
xylan onto cellulose surfaces. A rye arabinoxylan polymer with an
initial arabinose/xylose ratio of 0.53 was debranched with an oxalic
acid treatment as a function of time. The resulting samples contained
reduced arabinose/xylose ratios significantly affecting the molecular
architecture and solution behavior of the biopolymer. With this treatment,
an almost linear xylan with arabinose DS of only 0.04 was obtained.
The removal of arabinose units resulted in the self-assembly of the
debranched polymer in water into stable nanoparticle aggregates with
a size around 300 nm with a gradual increase in crystallinity of the
isolated xylan. Using quartz crystal microbalance with dissipation
monitoring, the adsorption of xylan onto model cellulose surfaces
was quantified. Compared to the nonmodified xylan, the adsorption
of debranched xylan increased from 0.6 to 5.5 mg m–2. Additionally, adsorption kinetics suggest that the nanoparticles
rapidly adsorbed to the cellulose surfaces compared to the arabinoxylan.
In summary, a control of the molecular structure of xylan influences
its ability to form a new class of polysaccharide nanoparticles in
aqueous suspensions and its interaction with nanocellulose surfaces.