Instrumented indentation was used to investigate the mechanical properties of coatings for automotive and architectural applications. First, the mechanical properties in the cross-section of a multi-layer acrylic-melamine automotive coating subjected to different processing steps were quantified. Indentation was able to distinguish the individual coating layers and showed that the interface between each layer was sharp on the 1 m measurement scale. This was confirmed by Raman line scan measurements. Indentation measurements showed that processing conditions did not impact the coating mechanical properties at the 1 m length scale. Second, the mechanical properties of a poly(vinylidene-fluoride-co-hexafluoropropylene) and a poly(methacrylate-co-ethyl acrylate) polymer blend, an architectural coating formulation, were characterized. Indentation measurements qualitatively agreed with DMA measurements of the modulus of the samples. It was shown that a threshold mass fraction of acrylic copolymer was required to increase the modulus of the blend, while the hardness of the sample continually increased with increased acrylic content. The creep behavior of these blends was measured and qualitatively analyzed by fitting a power law model.
Proceedings Title: Instrumented Indentation for Quantifying Quasi-static and Transient Properties of Polymeric Coatings
Conference Dates: October 15-16, 2008
Conference Location: Chicago, IL
Conference Title: FutureCoat!2008 "Globally Responsible Coatings: Getting There from Here"
Pub Type: Conferences
nanoindentation, raman microscopy, automotive coatings, polymer blends, creep