| Abstract: | The physicochemical aging for parts of Sheet Molding Compound should be considered for their lifetime management and reusability. This material has a complex morphology and contains porosity due to the process and to shrinkage compensation. This SMC study has two complementary approaches. One describes the morphological consequences of water uptake, showing the decrease in the total amount and the fractal dimension of micro-voids by scanning electron microscopy and image processing. The other shows, by mechanical spectrometry, the effect of water on physical or chemical bonds. In both cases, the “low profile agent” in SMC plays an important role. The molecular mobility was taken as a sensor parameter for the structural changes at the molecular scale, highlighting and quantifying the first steps of the aging. The loss factor level increases, and the activation energies are modified, even for the first aging days. The analysis shows recovery for the material near the relaxation peak of the low profile agent, since the curve recovers its initial shape. |
