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

the chemical treatment process alone resulted in visually identifiable structural changes from
SEM analysis. The chemical treatments applied are typically used for weakening the bonds
between the compacted cellulose structures before application of energy intensive mechanical
treatments (Wang and Sain 2007b). After both RSH and HPH processes, the morphology has
completely changed yielding a fabric-like network with few distinguishable fibers. Due to the
self-association of individualized cellulose fibers at the nanoscopic level, the development of a
fabric-like network could be expected after freeze drying. The distinguishable fibers observed
are of micron dimensions similar to fibers seen in the OM micrographs.
In order to observe smaller dimensions within the SMF samples, TEM micrographs were
obtained as shown in Figure 5.4. The three images show various size distributions found within
the SMF samples. It is clear that although micro dimensioned fibers were seen, nanofibers were
also obtained. These fibers are well under 50 nm similar to MFC particle types (10 – 100 nm) as
described by Moon et al. (2011). Size distribution of the cellulose fibers after chemo-
mechanical treatment therefore ranges from nano to micro dimensions. This rather wide range
of particle size could be due to the heterogeneous feedstock materials used.
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