Densification of a polymer glass under high-pressure shear flow

Advancements in Novel Mechano-Rheological Probes for Studying Glassy Dynamics in Nanoconfined Thin Polymer Films

“…Brazil et al noted an increase in densification in high M w PS films upon applying very large stresses in a confined compression test. Although it was expected that the increase in densification should plateau out once the load crosses over to the extrusion zone, there was a further increase in densification close to 3.4% even in the extrusion zone, which could not be explained by the volume-preserving plastic mechanics . The effect of densification could also be observed when applying the same load repeatedly to PS films and graphene nanosheet network.…”

“…Although it was expected that the increase in densification should plateau out once the load crosses over to the extrusion there was a further increase in densification close to 3.4% even in the extrusion zone, which could not be explained by the volume-preserving plastic mechanics. 353 The effect of densification could also be observed when applying the same load repeatedly to PS films and graphene nanosheet network. Sinnott et al 354 observed an increase in stiffness in the subsequent loading cycles.…”

“…On investigating the effect of a range of aspect ratio values on the confined modulus, using finite element simulations, it was found that the application of a simple substrate correction factor to the punch-substrate contact stiffness helped obtain the true stress–strain values that stay correct for the range of aspect ratio values investigated (5–100) . Brazil et al noted an increase in densification in high M w PS films upon applying very large stresses in a confined compression test. Although it was expected that the increase in densification should plateau out once the load crosses over to the extrusion zone, there was a further increase in densification close to 3.4% even in the extrusion zone, which could not be explained by the volume-preserving plastic mechanics .…”