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

was obtained as described in Section 4.2. Titanium dioxide nanoparticles, Aeroxide P25
(diameter ~21 nm), and P90 (diameter ~14 nm) with mixed anatase and rutile crystal structures,
was kindly donated by Evonik Industries (Hanau-Wolfgang, Germany). Both these types of TiO2
were of the same product line for applications of exploiting photocatalytic effects.
7.3 METHODS
7.3.1 SAMPLE PREPARATION
The formulation of blend films contained SPI (100 parts), water (70 parts), glycerol (50
parts) and varying amounts of additives at 0.25, 0.5, 1.0, or 2.5% (w/wSPI). Samples are
labeled according to additive and concentration with extracted soy microfibers, titanium dioxide,
and fiber/titanium blends denoted as F, Ti, and TiF respectively (Example: F0.25 reflects a
specimen containing 0.25g of fiber and 100g of SPI). Preliminary experiments were carried out
to determine the concentration and type of TiO2 (P25 or P90) that were to be used in the TiF
blended films. For the TiF specimens, TiO2 concentration was maintained at 0.25% (w/wSPI)
while the number labeled reflected the concentration of fibers added (Example: TiF0.5 reflects a
specimen containing 0.25% TiO2 and 0.5% fiber (w/wSPI)). Prior to power mixing (SM-55 Stand
Mixer, Cuisinart, Canada), additives were premixed with water and glycerol using a rotor/stator
homogenizer for 5 min at 30,000 rpm (PowerGen Model 1000, Fisher Scientific, Ottawa, ON,
Canada). Protein sheets were conditioned for 1 week in 43, 58, and 84% RH at 25°C using
saturated salt solutions before testing.
90