Interpenetrating Polymer Network IPN Tougheners

Such a mixture of networks is called an interpenetrating polymer network (IPN). Much higher shear strength and impact resistance are claimed for IPN epoxy systems than for standalone single networks, and at the same time the high-temperature strength is improved. 

Core-shell structures (Fig. 8.7) have also been suggested as a method of toughening epoxy resin formulations. The polymeric shell, which surrounds an elastomeric core, provides good adhesion to the epoxy matrix. Hyperbranched polymers with hydroxyl 

FIGURE 8.8 Interpenetrating polymer networks. (Courtesy Polymeries GmBH) 

Which Adhesives for Bonded Metal Assembly, Production Engineering, May 25, 1964. 

Farrakhov, A. G., and Khozin, V. G., Mechanical Behavior of Plasticized Epoxy Polymers, Crosslinked Epoxies, B. Sadlacek and J. Kahovec, eds., Walter de Gruyter and Co., Berlin, 1987, pp.585-597. 

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