Mechanical behavior of polyimide filament tows under high strain rate tension

Abstract

The tensile properties of polyimide (PI) filament tows were measured under quasi-static state and at high strain rates with a universal tensile testing machine and a split Hopkinson tension bar, respectively. Experimental results showed that mechanical behaviors of the tows were rather sensitive to strain rate, with failure stress and modulus increasing distinctly but the elongation at break declining as the strain rate increased. Besides, the PI filament tows exhibited a higher growth rate of fracture stress than para-aramid fiber and aramid III fiber did, and scanning electronic microscopy observation on the fracture surface indicated a ductile fracture mode. With the increase of strain rate, the axial splitting of fiber intensified. Further, strength distributions of the PI filament tows were evaluated by a single Weibull distribution function, and the curve predicted was in good accordance with the experimental data obtained.

The shape-retention and heat-tolerant elastic helix based on azobenzene-polyimide supramolecular assembly

“…As shown in Figure 7(b) and (c), it can be found that the cross-section morphology of the film is compact, and the cross-section roughness is believed to be caused by the ductile fracture of film. 20 The image of the cross section indicates that the thickness of the film is 9.8 μm. Furthermore, analysis of the variance method is applied to the study of the film thickness and film uniformity which were influenced by polymer concentration, spin velocity and spin acceleration in the process of spin coating (Figure 7(d)).…”

Enhanced Impact Properties of Hybrid Composites Reinforced by Carbon Fiber and Polyimide Fiber

“…When impacted by external force, it can absorb and dissipate energy through chain movement; the timely conversion of kinetic energy into thermal energy required by the thermal motion of molecular chains endows the fiber with excellent toughness. Our previous research indicated PI fiber underwent plastic deformation during quasi-static tension, while fibrillation occurred during high-strain-rate tension, both of which were conducive to energy absorption and thereby toughness enhancement [22]. Therefore, we decided to explore whether PI fibers and carbon fibers could be simultaneously adopted to prepare hybrid fiber-reinforced composites (HFRP), so as to make full use of the high toughness of PI fiber to balance the stiffness and toughness Polymers 2021, 13, 2599 2 of 9 of carbon fiber-reinforced composites (CFRP), and in the meantime, improve the impact resistance of composites.…”

Synthesis of waterborne epoxy resin with diethanolamine-assisted succinimide for improving the strand integrity of polyimide filament

“…High-performance fibers such as aramid fiber [1,2], carbon fiber [3,4], basalt fiber [5,6], glass fiber [7,8], and polyimide [9][10][11][12][13][14][15] have broad application prospects in the military, transportation, construction, electronic, aerospace, and electrical fields, due to their high strength, high modulus, and high-temperature resistance. Polyimide (PI) filament is a species of high-performance fiber with the imide ring structure in the molecular chain.…”