THE SURFACE EMBRITTLEMENT OF A DUCTILE BLEND DUE TO A BRITTLE PAINT LAYER

The surface embrittlement phenomenon has been studied on a coated poly mer by means of instrumented falling weight impact tests. The specimen s are made of a ductile blend, used in the car industry, coated with a double layer paint system composed of a primer and a top coat. The en ergy absorbed during the impact test is correlated with the viscoelast ic spectra and tensile properties of both the blend and paint system c omponents. The viscoelasticity of the coating system is found to be th e crucial parameter of the embrittlement. In the case of a brittle coa ting its thickness must exceed a critical value to embrittle the subst rate.