Creep resistance enhancement and modeling of 3D printed Polyetherimide/carbon black composites

This study investigates the potential of carbon black (CB) reinforcement to enhance the mechanical properties of high-performance Polyetherimide (PEI) compromised by Material Extrusion (MEX), making them comparable to those produced by conventional methods. PEI filaments with varying CB fractions (5 – 20 wt%) were produced, and creep test specimens were fabricated via MEX. A neat PEI hot-pressed specimen was also manufactured for comparison. The results demonstrated a 7% increase in ultimate tensile strength (UTS), alongside 14% decrement in creep strain with 5 wt% CB reinforcement, approaching the performance of conventionally manufactured neat PEI. Creep behavior was modeled using Burgers, Kelvin–Voigt, and Findley models, with Findley's model proving effective in capturing instantaneous strain. Additionally, the Time–Temperature Superposition Principle (TTSP) was applied to develop creep master curves up to 10⁹ s. This study highlights the potential of CB as a cost-effective reinforcement material to improve the mechanical properties of 3D-printed high-performance polymers.