Polymerization-induced phase separation and resulting thermomechanical properties of thermosetting/reactive nonlinear polymer blends: A review

Thermosets, which have a highly crosslinked structure, play a pivotal role in high-performance composite materials because of their excellent mechanical properties, including their high modulus, high strength, and high glass-transition temperature. In general, however, thermosets are brittle materials with a toughness and elongation at break that are unsatisfactory for many applications, especially at high temperatures. The key factor that can greatly influence the toughness of a thermoset material is its cured microstructure or nanostructure. Recently, it has been revealed that the introduction of a reactive modifier into a multicomponent thermosetting prepolymer is a versatile way to finely tune the polymerization-induced phase separation (PIPS) and the microstructure and thermomechanical properties of the resulting thermosets. This review focuses first on the advancement of the methods used to study the PIPS of thermosetting prepolymers. I go on to discuss factors influencing the thermodynamic and the kinetic behavior of PIPS and the resulting morphology and thermomechanical properties of thermosetting blends obtained when nonlinear reactive modifiers are incorporated. (c) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013