THESIS - ROC CH ... - FINAL - resubmission.pdf - University of Guelph
THESIS - ROC CH ... - FINAL - resubmission.pdf - University of Guelph
THESIS - ROC CH ... - FINAL - resubmission.pdf - University of Guelph
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Modulus <strong>of</strong> Elasticity (MPa)<br />
200<br />
180<br />
160<br />
140<br />
120<br />
100<br />
80<br />
60<br />
40<br />
Figure 7.9: Modulus <strong>of</strong> elasticity <strong>of</strong> SPI films blended with cellulose (F), TiO2 (Ti), and cellulose<br />
compatibilized with TiO2 (TiF)<br />
43% RH 58% RH<br />
84% RH<br />
0 0.5 1<br />
Concentration (%w/wSPI)<br />
0 0.5 1<br />
Concentration (%w/wSPI)<br />
These mechanical properties suggest a synergistic effect might be present with the use<br />
<strong>of</strong> TiO2 as a coupling agent for cellulose in SPI film. This may be explained by enhanced<br />
cellulose-TiO2 interactions and subsequent decrease in cellulose-cellulose interactions.<br />
Previous investigations on the adsorption <strong>of</strong> TiO2 on cellulose fibers have speculated that van<br />
der Waals and electrostatic forces cause TiO2 to be more strongly attracted to the smaller fibrils<br />
surrounding beaten cellulose fibers (Siffert and Metzger 1991). The surrounding fibrils in this<br />
study were likened to a gel-like coating on the surface <strong>of</strong> larger cellulose fibers as described by<br />
Kibblewhite (1972). The extracted cellulose in the present experiment also exhibited similar gel-<br />
like appearance as described. This may provide many opportunities for interaction between<br />
cellulose and TiO2 during the rotor/stator homogenization step. In addition, the small dimensions<br />
<strong>of</strong> both fibers and TiO2 increases surface area which could also enhance interactions between<br />
them. Past studies also mentioned the use <strong>of</strong> TiO2-coated cellulose fibers for forming paper<br />
105<br />
0 0.5 1<br />
Concentration (%w/wSPI)<br />
F<br />
Ti<br />
TiF