FTIR Imaging via FPA in the Characterization of Polymers

Fourier-transform infrared spectroscopy (FTIR) can provide valuable evidence for changes to polymer materials due to environmental effects such as polymer degradation. It can also detect the presence of certain solvents or contaminants and/or detect migration of components from one polymer to another. To characterize the chemical changes in the polymer due to environmental effects, FTIR using attenuated total reflection (ATR) is often utilized due to the simplicity of analysis and wide distribution of these instruments in the failure analysis community. But the ATR method of FTIR spectroscopy does not provide an accurate representation of the state of the polymer material below the first few microns since the method only collects data from this depth of material adjacent to the ATR crystal. The micro-FTIR method of FTIR spectroscopy can circumvent some of this by allowing pinpoint measurements below the polymer surface, but it also requires collection of individual spectra at discreet single points on a cross-section of a sample.

Herein we will demonstrate how more advanced methods using FTIR with a focal plane array (FPA) detector are superior for characterizing the depth of environmental effects in the polymer. This technique allows for the acquisition of spectra across a two-dimensional plane to image a larger, more representative area of the surface rather than accumulating single point measurements. The data can be reviewed using a 2D or 3D heatmap to more comprehensively study and visualize the resultant data.