Epoxy network modified/toughened

Figure 13.10 Toughness (K C) and toughening mechanisms of epoxy networks modified with 10 phr CSR versus molar mass between crosslinks, Me (O) neat systems ( ) with 10 phr CSR. (Adapted from Lu, 1995.)...

While the surface modification is not effective to suppress cavitation, Yee and coworkers performed an experiment to suppress the cavitation mechanically in a rubber-modified epoxy network. They applied hydrostatic pressure during mechanical testing of rubber toughened epoxies [160]. At pressures above BOSS MPa the rubber particles are unable to cavitate and consequently no massive shear yielding is observed, resulting in poor mechanical properties just like with the unmodified matrix. These experiments proved that cavitation is a necessary condition for effective toughening. 

Hed Hedrick, J. L., Yilgor, I., Jurek, M., Hedrick. J. C., Wilkes, G. L., McGrath, J. E. Chemical modification of matrix resin networks with engineering thermoplastics 1. Synthesis, morphology, physical behaviour and toughening mechanisms of poly (arylene ether sulfone) modified epoxy networks. Polymer 32 (1991) 2020-2032. 

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