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

Modulus of Elasticity (Mpa)
100
90
80
70
60
50
40
30
20
10
0
43% RH
60% RH
84% RH
0 CNF 0.25 CF 0.25 CF 0.5 CF 1 CF 2.5
Fiber Content (% w/w SPI)
Figure 6.7: Modulus of Elasticity with respect to fiber content and relative humidity
Figure 6.8 displays the percent elongation at break for all composite films. The change in
relative humidity can be seen to have no significant effect on the performance of elongation.
The values and level of decrease observed were very similar across all levels of relative
humidity. However, it is noted that a higher variability of results were experienced with higher
RH of 84%. The weakening of microscopic defects of the films was exaggerated leading to more
inconsistencies at film failure. Increasing fiber concentrations resulted with no significant effects
on elongation. Films with the addition of fiber up to 1% w/w fiber/SPI, all resulted in similar
elongation values of ranging from 168.75 ± 0.11 to 242.00 ± 23.45%. The significant difference
was observed with the maximum loading of fibers with SMF2.5 specimens where elongation
values decreased across all three levels of RH from 103.49 ± 10.73 to 118.85 ± 26.83%. This
drastic decrease in elongation may be caused by the defects seen in the micrographs. In
addition, the formation of aggregates spread throughout the films would increase stress
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