Features of IPN Morphology

The morphology of IPNs is determined by the mechanism of phase separ-ation-nucleation and growth or spinodal decomposition. As was discussed above, the application of direct structural methods for studying IPNs is rather restricted due to their amorphous state and low degree of ordering. Because 

Presently, a great deal of work is published concerning the structure of IPNs obtained using electron microscopy. From the preceding discussion it is evident that the morphology of IPNs should be determined by the following factors (1) the thermodynamic miscibility of two networks, (2) the kinetic conditions of the curing reactions, and (3) the mechanism of phase separation. In principle, three distinct features of IPN structure should be revealed. 

The first case is the absence of any structure for miscible and full interpenetrating of different chains. The difficulty consists in the practical impossibility to directly measure the interpenetration degree [161]. 

A very interesting observation was made by studying simultaneous IPNs formed by epoxy resin and PBMA [163]. The electron microscopy pictures show distinct two-phase morphology, which allows the dimensions of phases to be determined. It was found that if IPNs were obtained under conditions 

Sperling [16] believes that the results of investigation of many sequential IPNs lead to the following generalizations  

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