Mechanisms of Inhomogeneous Polymer Weathering

The strength, impact toughness, and fractography of degradation of epoxy polymer and poly(methyl methacrylate) were studied during aging under conditions of moderate warm and warm humid climates. Heterogeneity of aging of the materials in thickness of specimens was detected. A common regularity of aging of amorphous and partially crystalline polymers is the formation of a degraded surface layer 100–200 μm thick. Principles of linear fracture mechanics were used to take into account the effect of this layer on the change in mechanical properties of polymers.