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a) b - École Polytechnique de Montréal

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in the rheology tests were compression moul<strong>de</strong>d at 190°C. In or<strong>de</strong>r to <strong>de</strong>termine the linear<br />

viscoelastic region, a stress sweep test was performed. The Carreau-Yasuda mo<strong>de</strong>l(Yasuda, et<br />

al., 1981) was employed to <strong>de</strong>termine the zero shear viscosity of PVDF.<br />

5.3.3 Substrate Preparation<br />

Multi-component blends were prepared via melt-blending un<strong>de</strong>r a flow of dry nitrogen in a<br />

30mL Plasti-Cor<strong>de</strong>r internal mixer (Braben<strong>de</strong>r) operating at 200°C and 50 rpm. The maximum<br />

shear rate at this speed is close to 25 s -1 . The real temperature achieved by the end of mixing<br />

experiment was approximately 185°C. After converting the mass to volume (<strong>de</strong>nsities presented<br />

in Table 5-1), the mixing chamber was filled to 70% of its total volume. All the blends in this<br />

study were mixed for 8 min which is more than sufficient to allow the torque to achieve a<br />

constant value. Irganox antioxidant, supplied by CIBA, was ad<strong>de</strong>d to the mixture at a level of 0.2<br />

wt% to reduce the thermal oxidation of the components. After mixing, the samples were<br />

immediately cut from the mass and quenched in a cold water bath to freeze-in the morphology.<br />

All concentrations have been reported based on the component volume fraction shown in Table<br />

5-2.<br />

Table 5-2. Composition of Polymer Components in Ternary and Quaternary Blends<br />

Samples HDPE PS PMMA PVDF<br />

A 33.3% 33.3% 0 33.3%<br />

B 33.3% 0 33.3% 33.3%<br />

C 40% 30% 10% 20%<br />

D 40% 10% 40% 10%<br />

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