Macrovoid distribution

In that case, significant transverse flow develops, and macrovoids may be entrapped as illustrated in Rg. 9.20. From the solution procedure point of view, fully three-dimensional flow modeling and simulations are not much more difficult than the two-dimensional version however, one needs (1) to discretize the solution domain in 3D instead of 2D (which takes much longer CPU time to solve the pressure distributions and advance the flow front in a time marching scheme) and (2) to measure the transverse permeability of the preform which is much more difficult than measuring in-plane permeability components. ... 

Figure 10.12 Visualization of 3D reconstructed PSU HF of Figure 10.10 description of the distribution of the macrovoids.

TIPS was reported to possess the ability to produce macrovoids-free membranes with superior mechanical properties and narrow pore size distribution [111]. In addition, the aforementioned process was able to produce a relatively thick symmetric microporous membrane for controlled release applications [28]. Although some studies claimed that TIPS has the advantage of fewer control parameters over NIPS, the high processing temperature and limited choice of high boiling point diluents are the main hurdles of TIPS [28,110]. 

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