Synchrotron infrared microspectroscopy characterization of heterogeneities in solid-state blended polymers

Immiscible polymers, including polystyrene (PS) and polyethylene terephthalate (PET), were blended in the solid state via mechanical attrition, the first step of a near net-shape manufacturing (NNSM) technique. Subsequent analysis via Fourier Transform Infrared Spectroscopy (FT-IR) with synchrotron radiation successfully distinguished between blend components. Characteristic absorbance peaks for each polymer allowed both qualitative and quantitative mapping within prepared samples. Reproducible area maps were created for 50/50 blends of polymethylmethacrylate (PMMA)/PET and PET/PS, which exhibited areas of macroscopic phase separation. Fluctuations in blend concentration were particularly evident for PS/PMMA. However, spatial resolution was shown to limit the detection of heterogeneities. Further modifications with the synchrotron IR apparatus will improve resolution and allow for the direct comparison of NNSM-processed and melt-blended polymers.