Improving mechanical properties of melt‐spun polyetherimide monofilaments by thermal drawing

Abstract

Super engineering plastics, such as polyetherimide (PEI), are widely used in various fields owing to their multifunctional properties. PEI is used in automobiles, electronics, and medicine owing to its high thermal resistance, excellent mechanical strength, flame retardancy, and chemical resistance. In this study, melt‐spun PEI filaments were thermally drawn and the effect of the drawing process conditions on their mechanical properties was investigated. To understand the mechanical properties of various forms, such as films, sheets, granules, tubes, and rods of PEI postprocessing, it is based on analyzing the behavior in one‐dimensional structures. The mechanical properties of the PEI filaments were dictated by the draw ratio, process temperature, and cooling temperature of the thermal drawing process. In addition, maintaining the drawing process temperature around the glass transition temperature (220°C) of PEI elongated the filament by up to 80%. Furthermore, the optimized cooling temperature was 150°C and draw ratio was 50%. In conclusion, PEI filaments with excellent mechanical properties were obtained by optimizing the draw ratio, process temperature, and cooling temperature of thermal drawing. Through the behavior of the molecular and crystal structures by thermal drawing of PEI filament, it is expected to be applied to two‐ or three‐dimensional structures.