Innovations in the processing of polymers and polymer mixtures can have unintended consequences for microstructure. Microscopic investigations have been motivated in some cases by acquisition of new processing machinery which is larger, such as the supercompounding extruders. Strategies to expand the capacity of existing machines also necessitate detailed property and morphology comparisons between old and new batches of commercially important blends.

Other types of innovations use a temporary processing aid. Dispersed phase size reduction in melt blends on addition of supercritical carbon dioxide has been reported for PMMA/PS blends. TEM images showed smaller, more uniform domains attributed to reduction in melt viscosity. Blends are also under investigation now in flash spun plexifilament fibers to extend the range of end-use properties, but the need for a common solvent limits the possible pairs of polymers. A two-step R.UO4 vapor staining procedure, in which the bulk and sectioned material are exposed, has been used to examine non-equilibrium morphologies frozen in from flash spinning.