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

For mechanical treatments, the obtained SF was broken down by a rotor/stator
homogenizer (RSH) and high pressure homogenizer (HPH). The use of the RSH was crucial for
continuous operation of the HPH whereby a homogenously suspended sample was needed for
smooth processing. Chemically treating SF yielded only partially suspended fibers with many
large fragments that still remained which clogged the HPH during operation. Using the RSH, the
chemically treated SF was defibrillated for 5 min (PowerGen model1000, Fisher Scientific,
Ottawa, ON, Canada). The resulting cellulose/water suspension was fed through the HPH for 20
passes at 4000 to 6000 psi to obtain SMF (APV Gaulin Laboratory Homogenizer Model 15MR,
Concord, ON, Canada).
5.3.2 MORPHOLOGICAL ANALYSIS
Optical microscopy micrographs of cellulose suspensions were obtained using a
polarized filter lens (Model BX60 F5, Olympic Optical Co. LTD, Japan). SEM images were
obtained after freeze drying of specimens. Procedure for SEM analysis was performed as
described in Section 4.3.7. Transmission electron microscopy (TEM) micrographs were
obtained using a Philips CM10 (Philips, Eindhoven, Netherlands) operated at 80 kV. A drop of
cellulose/water suspension was placed on a copper grid coated with formvar as support. A
settling time of 30 sec was allowed for fibers to rest. Tissues were used to remove excess
water. Staining of the fibers for contrast utilized 2% of uranyl acetate in water and applied for 10
s. Excess stain was absorbed with tissues.
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