THESIS - ROC CH ... - FINAL - resubmission.pdf - University of Guelph

increased in size. At fiber concentrations below 0.5% w/w SMF/SPI, the appearance of flakes
was minimal to non-existent. Upon FTIR analysis of these fractions, they were found to be
aggregated cellulose fibers. Further analysis on the protein melt from the screw flights within the
extruder showed that large fragments could be found loosely adhering to the bulk SPI melt. As
seen in Figure 6.2a, the large fractions were mainly concentrated against the barrel walls and
surfaces of the screw. No signs of chemical association were observed as clear separation of
the fragments from the bulk SPI melt was apparent. This phenomenon again was dependent on
the concentrations of fiber added to the mixture. With low additions of fiber (0.25 and 0.5% w/w
SMF/SPI), few to no fragments were seen inside the extruder barrel.
a
Figure 6.2: Presence of cellulose rich agglomerates observed throughout the process of
extrusion. a) Aggregate formed inside the extruder barrel wrapping around screw. b) Clumps seen
through strand formation after compounding. c) Aggregated fragments embedded in
SPII/cellulose blend films at high fiber loadings.
b
Progressing to extrusion findings, the presence of cellulose rich domains was also
observed. Large particles were embedded randomly throughout extruded films (Figure 6.2c).
The phenomenon was exaggerated with higher fiber concentrations (1.0% and 2.5% w/w
SMF/SPI). However at concentrations of 0.5% w/w SMF/SPI and below, the presence of these
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c