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a) b - École Polytechnique de Montréal

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in the respective blend viscosity until, at the phase inversion point, the maximum viscosity is<br />

reached.<br />

Luciani et al.(Luciani & Jarrin, 1996), based on Tomotika’s theory and the relative stability of<br />

networks created by coalescence, <strong>de</strong>veloped the following equation:<br />

Equation 2-23.<br />

φI 2<br />

2<br />

⎛η<br />

⎞ ⎛ ⎞<br />

1 2 η1<br />

⎜<br />

⎟ Ω ⎜<br />

⎟<br />

⎝η2<br />

⎠ ⎝η2<br />

=<br />

⎠<br />

⎛ ⎞<br />

2<br />

⎜ ⎟<br />

⎛η<br />

⎞ ⎛ ⎞<br />

1 2 η1<br />

2<br />

Ω + Ω ⎜ 1 ⎟<br />

⎜<br />

⎟<br />

⎜<br />

⎟<br />

⎝η<br />

⎠ ⎝ ⎠ ⎜ η1<br />

⎟<br />

2 η2<br />

⎜ ⎟<br />

⎝ η2<br />

⎠<br />

where ⎟ ⎛η<br />

1 ⎞<br />

Ω ⎜ , λ is a complex function of both the viscosity ratio and observed wavelength of the<br />

⎝η<br />

2 ⎠<br />

distortion λ in Tomotika’s equation.<br />

The other semi-empirical mo<strong>de</strong>l which accounts for the viscous properties of the polymers was<br />

proposed by Willemse et al.(Willemse, <strong>de</strong> Boer, van Dam, & Gotsis, 1998) based on geometrical<br />

requirements for the formation of co-continuous structures:<br />

Equation 2-24.<br />

1<br />

⎛η<br />

& mγ<br />

⎞<br />

= 1.<br />

38 + 0.<br />

0213⎜<br />

R0<br />

⎟<br />

φ<br />

⎝ σ ⎠<br />

d<br />

where ηm is matrix phase viscosity, R0 is the initial radius of the droplet before <strong>de</strong>formation into<br />

a cylin<strong>de</strong>r, and σ is interfacial tension. This equation can <strong>de</strong>termine the composition range over<br />

which co-continuity exists and gives the lower limit of continuity for component 1 and upper<br />

limit for component 2.<br />

Steinmann et al.(Steinmann, Gronski, & Friedrich, 2002) <strong>de</strong>rived the following equation point,<br />

assuming that phase inversion occurs at maximum shape relaxation times of domains of<br />

components:<br />

Equation 2-25.<br />

1<br />

1<br />

1 ⎞ z<br />

φ<br />

2I<br />

=<br />

⎛η<br />

⎜<br />

⎟<br />

⎝η<br />

2 ⎠<br />

+ 1<br />

4.<br />

2<br />

18

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