Weathering action on thermo-viscoelastic properties of polymer interlayers for laminated glass

Mechanical properties of interlayer polymers are recognized to be essential for a correct design of lam- inated glass structures. Although several researches have been carried out on the consequences of weath- ering actions on a laminated glass, few quantitative data on the properties of polymers are available. The response of structures to a long duration load is therefore evaluated taking into account the effects of vis- cosity of the interlayer, but in the hypothesis that the interlayer material does not degrade over time. In this paper the results are reported of an experimental analysis of the thermo-viscoelastic properties of polyvinyl butyral used as interlayer of laminated glass, subjected to weathering actions (humidity, ther- mal cycles and UV radiation). The results were interpreted in the light of the connection between microstructure and rheology of polymers, and highlight two different damage mechanisms, promoted in different extents by the different weathering actions.