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

4.3 METHODS
4.3.1 SAMPLE PREPARATION
The formulation of the SPI film contained 100 parts SPI, 70 parts water, and 50 parts
glycerol, by weight. The preparation of SPI film was first done by premixing water and glycerol.
The premix solution was added to SPI using a programmable dispensing pump (DP-200, New
Brunswick Scientific Co., INC, Edison, New Jersey, USA) at a controlled rate of 6 mL for every 2
seconds. A kitchen mixer (SM-55 Stand Mixer, Cuisinart, Canada) was used to continually mix
the materials during the course of solution addition. Mixing speed was set to the maximum and
was left to mix for 15 min. The mixture was equilibrated for 12 hours in a sealed plastic bag prior
to extrusion.
4.3.2 COMPOUNDING AND EXTRUSION
Compounding and extrusion were done using a lab scale extruder, Microtruder RCP-
0625, Randcastle, New Jersey, USA (Figure 4.1a). The extruder features 4 heating zones as
seen in Figure 4.2a. The first three zones are along the barrel with the fourth zone controlling
interchangeable heating cartridges situated inside the strand die (Figure 4.1c) or the lip die
(Figure 4.1b). The slit in the lip die is height adjustable with a maximum gap of 0.046 inches.
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