Chemical Engineering July 2010 - 16

Produce polymer nanofibers at greater yield and control
CHEMENTATOR
N
ew technology for fabricating nanoscale
polymer threads boosts yields
and improves control compared to conventional
methods for producing nanoscale
fibers by using a technique analogous
to that for making cotton candy.
The technology, known as rotary jet
spinning (RJS), was developed by engineers
at Harvard University (Cambridge,
Mass.; www.harvard.edu) and is
described in a recent paper in the journal
Nano Letters.
In RJS, a high-speed rotating nozzle
is attached to the shaft of a controllable
LIGNITE DRYING-AND-REFINING SYSTEM
(Continued from p. 13)
In addition, the refining component of
DryFining segregates the lignite stream
and removes the higher density compounds
that contain higher levels of sulmotor.
Rotation propels the polymer solution
through a nozzle capillary, and
the outward centrifugal force stretches
the extruded polymer. Simultaneously,
the polymer solvent evaporates, solidifying
the material into threads of around
100-nm dia. The extruded fibers then
deposit on a circular collector. Nanofiber
production output for RJS is " many
times greater " than conventional techniques
for making nanofibers, such as
electrospinning, says Harvard bioengineer
Kit Parker, who heads the group
where the method was developed.
fur and mercury. As a result, emissions
are also reduced, namely, SO2 and Hg by
more than 40%, NOx by more than 20%
and CO2 by 4%.
The process has been developed
through a number of DOE grants, starting
in 2003, which culminated in the
Lead author Mohammad Reza
Badrossamy says the RJS system has
formed fibers from a variety of synthetic
and natural polymers, including
polylactic acid in chloroform, gelatin in
mild acetic acid and polyethylene oxide
in water.
By changing nozzle rotation speed
and solvent volatility, the researchers
can control the fiber thickness and morphology.
Nanofibers could have a wide
variety of applications, including textiles,
air filters, bio-scaffolds and others,
say the scientists.
startup of a commercial system (four
units, each processing 135 ton/h of coal)
at Coal Creek Station, which started up
last December. The DryFining system
will be licensed through a partnership
with WorleyParsons (Sydney, Australia;
www.worleyparsons.com).
n
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Circle 2 on p. 58 or go to adlinks.che.com/29252-02
16 CHEMICAL ENGINEERING WWW.CHE.COM JULY 2010
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Chemical Engineering July 2010

Table of Contents for the Digital Edition of Chemical Engineering July 2010
