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

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