(65p) Solid-State Fabrication of Polymer Blends: Cryogenic Milling and Solid-State Shear Pulverization

Blending of two or more polymers can allow for tailored materials with highly tunable and customizable attributes, and are of interest in both industry and research. However, most polymer combinations are thermodynamically immiscible and current methods of polymer blend production have significant limitations. In immiscible blends, reactive extrusion or introducing a third ?compatibilizer? species can ?compatibilize? the resulting systems, but are only applicable to specific polymer families or chemically-modified polymers.

Studies have been conducted using mechanochemical reactions to prompt polymer chain scission, which can generate compatibilizing block copolymers from the component species in situ via free radical formation and recombination. Two techniques which utilize such mechanochemical principles are cryogenic milling and solid-state shear pulverization (SSSP). Cryogenic milling is a batch-scale process in which polymer pellets are contained within a processing vial and ground via a magnetically-driven tungsten carbide impactor. SSSP utilizes a continuous twin-screw extruder operating at below ambient temperatures.

This study focuses on comparing polymer blends made via common melt-state processing techniques to those fabricated through both batch cryogenic milling and continuous SSSP. Current results indicate phase stabilization and compatibilization via both methods.