Synergistic effects of short glass fiber/short carbon fiber hybrids on the mechanical properties of polyethersulfone composites

Abstract

Polyethersulfone (PES) is one of important high performance engineering thermoplastics but its mechanical and tribological properties are not comparable to those of metals and have to be enhanced in order to widen its applications. In this work, both short glass fibers (SGFs) and short carbon fibers (SCFs) are employed to reinforce PES and the SCF/SGF/PES composites were prepared using melt blending and injection molding techniques. The simultaneous usage of SCFs and SGFs with various volume ratios is to examine their possible synergistic effects in reinforcing PES. The results reveal that the tensile and flexural properties as well as wear resistance are all enhanced by the addition of both SCFs and SGFs. The tensile/flexural strength and modulus of the hybrid PES composites increase with increasing the SCFs volume fraction in fillers. Meanwhile, the friction coefficient and specific wear rate of the hybrid PES composites decrease with increasing the SCFs volume fraction in fillers. Interestingly, the tensile strength, flexural strength and wear resistance of the hybrid SCF/SGF/PES composites at proper SCF/SGF volume fraction ratios are obviously higher than those predicted by the rule of mixtures, representing the typical positive synergistic effects of SCFs and SGFs. Consequently, it is promising to employ both expensive SCFs and cheap SGFs at proper SCF/SGF volume fraction ratios for reinforcing PES in considering the combination of properties and cost. POLYM. COMPOS., 40:E1725–E1731, 2019. © 2018 Society of Plastics Engineers

An assessment of mechanical behavior of glass fiber/epoxy composites with secondary short carbon fiber reinforcements

“…Nevertheless, the interfacial area of SCF/epoxy, affected by varying SCF concentration, becomes the primary aspect that directs the strength of the composite. Additionally, carbon fiber exhibits good strength and stiffness as well as a smaller mean aspect ratio than glass fiber, so that SCF behaves as a practical load bearer in the composite 46 …”

“…This is because SCF has high aspect ratio, thereby revealing a large surface area, so they tend to form agglomerated bundles that reduce their net free energy at high concentrations. So, the practical aspect ratio diminishes, stress concentration increases, and the composite fails at a lower stress 61 …”

“…Rahmanian et al 43,44 also used CNT and short carbon fibers in epoxy for improving the fracture behavior, modulus and strength of epoxy. Short carbon fibers and short glass fibers as reinforcements in a thermoplastic base also show positive synergetic effect 33,45,46 …”

The effect of hybridization on microstructure and thermo-mechanical properties of composites reinforced with different weaves of glass and carbon fabrics

“…Whereas, if the experimental results are higher than the estimated values, this is known as the positive hybridization effect and is generally termed as the "synergistic effect". 20,21 Many researchers in the past have successfully utilized the hybridization technique to enhance the mechanical properties of glass/carbon fiber (hybrid) composites. [22][23][24][25][26][27][28] For example, Zhang et al 29 studied the effect of hybridization on the mechanical properties of glass and carbon fabrics reinforced epoxy composites by manufacturing three different types of hybrid composites based on various stacking sequences.…”

“…Whereas, if the experimental results are higher than the estimated values, this is known as the positive hybridization effect and is generally termed as the “synergistic effect”. 20,21…”