In situ formation of polymer nanofibrils during compounding with a second polymer followed by their immediate solidification due to shear induced crystallization for two pairs of polymers is described.

Severe plastic deformation (SPD) has come to the fore over the last decades as a potent way to improve the mechanical and physical properties of metallic materials. The use of such techniques for polymers has a long history and can be proud of its significant achievements, but they are less familiar to the metal research community. This review provides insights in the use of SPD techniques to modify the microstructure and properties of polymers and summarizes the salient results obtained in this area. It is hoped that this exposé will be of interest to the broader materials community, beyond the borders of polymer research.