3D Raman images of rubber blends (IR–HNBR)

The morphology of rubber blends was studied by means of confocal Raman spectroscopy, this latter being used as an imaging tool. Two immiscible rubbers were blended at different concentrations to test the ability of Raman spectroscopy for analysing a three-dimensional (3D) heterogeneous structure. These rubbers exhibited distinct vibrational signatures allowing us to identify them unambiguously. The samples were analysed as a function of depth (Z-axis) by modifying the focus of laser beam from Raman microscope. For each given value of depth Z, a flat surface was scanned in both X and Y directions. Thus, three-dimensional images were built by using a homemade software. The results obtained by Raman spectroscopy were compared to those stemming from scanning electron microscopy (SEM). This study clearly showed that the identification of rubber phases and the morphology of rubber blends as a function of their composition can be assessed by Raman spectroscopy.