Pure water, void size

Figure 6.7 Effect of initial pure water void size on the final void size for the process conditions shown...

Figure 6.7 shows the final diameter of a pure water void at the end of the cure cycle after it has grown from voids of various initial diameters under the conditions specified. For an initial void diameter of zero, the final diameter is about 1.25 cm under the specified conditions of growth. On the other hand, relatively large initial void diameters (0.5 cm) only triple in size. 

The final diameter of a pure water void for different initial relative humidities of the resin is shown in Figure 6.8. The marked increase in the final void size illustrates the pronounced effect that initial relative humidity exposure has on the final void size. This behavior is described by Equation 6.28 in which CTO (which is fixed during the cure cycle and determines the driving force) increases with the square of the initial relative humidity exposure. Thus, increasing the initial relative humidity by a factor of 2 would result in a four-fold increase in C oo. This would in turn increase the driving force 4-fold when the other conditions of growth are kept identical and when Csat [Pg.197]

Figure k shows the mechanism of what is generally referred to as reverse osmosis in the marketplace. As you can see, the pore size is approximately equal to twice the thickness of the pure water layer over the membrane which is void of any ions. 

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