Structure‐Property relationships in polyacrylate‐poly(urethane‐urea) interpenetrating polymer networks

Interpenetrating polymer networks of polyacrylate (A) and poly (urethane‐urea) (U) were prepared by mixing lattices of self‐curing polyacrylate and urethane‐urea prepolymer followed by subsequent curing of each network. The structures of the mixtures were analyzed by the dynamic viscoelasticity and the electron microscopy. It was found that a phase inversion occurred from the “U‐phase particles in A‐phase matrix” to the “A‐phase in U‐phase matrix” at A/U ≑ 30/70 as the U‐phase content increases.

With increasing A‐phase content, tensile strength started to increase and elongation‐to‐break becomes almost constant after the A‐phase formed a continuous phase. This implies that the tensile properties are closely related to the morphological features.