Compatibilization in phase-separated interpenetrating polymer networks

The effects of various potential compatibilizers on the viscoelastic properties and kinetics of formation of semi-IPN based on crosslinked polyurethane and linear poly (butyl methacrylate) have been investigated. All the compounds investigated affect the reaction rate of formation of components of IPNs. Depending on the nature of compatibilizers the phase separation in forming system may be accelerated or eliminated. In ail cases, the dependencies of mechanical loss tangent on temperature show instead of two relaxation maxima in the initial IPN, one broad or diffuse maximum. The different types of the compatibilizing action may be distinguished. In one case, the additive introduced into the initial reaction system prevents microphase separation and leads to the formation of ternary thermodynamically compatible IPN, which characterizes by a single relaxation maximum. In other cases, the compatibilizers accelerate microphase separation in the IPN, which begins at a lower degree of conversion for each IPN component. The single relaxation maximum in these IPNs is the result of changing the morphology of the system.