EFFECT OF POST-PROCESSING ANNEALING ON CRYSTALLINITY DEVELOPMENT AND MECHANICAL PROPERTIES OF POLYPHENYLENE SULFIDE COMPOSITES PRINTED ON LARGE-FORMAT EXTRUSION DEPOSITION SYSTEM

摘要

This work investigates the effect of annealing on structure development and mechanical properties of parts printed on a large-format extrusion additive manufacturing system using short carbon fiber reinforced polyphenylene sulfide (PPS). PPS, being a semi-crystalline polymer, offers the potential to alter the mechanical properties of parts with changes in crystallinity. Annealing PPS at temperatures above the glass transition and below the melting point for long hours can enhance crystallinity in the material, thereby improving the mechanical properties. However, high temperature polymers such as PPS can also undergo reactions (branching and/or crosslinking) when annealed in an oxidative environment, which further influence crystallization. This work reports the effect of annealing on the changes in crystallinity, possibility of chemical reactions taking place, melt rheological properties and thermo-mechanical properties of the chosen PPS grades.