Strain rate dependent metrics for high performance Polyphenylene Sulfide (PPS) in material extrusion additive manufacturing

High-performance polymers (HPP) fabricated through material extrusion (MEX) 3D printing, such as polyphenylene sulfide (PPS), are utilized in the production of lightweight and high-quality components. Nonetheless, their mechanical response under varying strain rates has not been thoroughly investigated. This study presents an analysis of the mechanical behavior of MEX 3D printed PPS parts subjected to load rates up to 300 mm/min. Raw PPS was processed into filament and employed to produce tensile testing specimens. A consistent increase in tensile strength, elastic modulus, and toughness was observed with increasing loading rates. At the highest load rate applied, the enhancement in mechanical properties was approximately 20% (around 60% for toughness). This behavior is anticipated due to the strain-rate strengthening characteristic of polymers, which is attributed to the reduced molecular chain flow. The sensitivity index m reached its maximum value at 200 mm/min and its minimum at 100 mm/min. The morphology of the samples was examined using scanning electron microscopy, revealing brittle behavior. Thermal behavior was assessed through thermogravimetric analysis and differential scanning calorimetry. These findings underscore the importance of considering the effect of strain-rate on mechanical properties when designing MEX 3D printed PPS components for use under high load rate conditions.