Can the maximum volume fraction ensure optimum reinforcement in short-fiber composites?

CRUCES, FLORENCIA; GARCÍA, MARÍA GUADALUPE; OCHOA, NELIO ARIEL

JOURNAL OF APPLIED POLYMER SCIENCE

JOHN WILEY & SONS INC

Año: 2019 vol. 136

0021-8995

Short sisal fiber composites (SSFCs) based on a pectin matrix were prepared and characterized mechanical and optically. Different concentrations (1?30 wt %) of fibers were used to evaluate the packing effect on the reinforcement of a polymer matrix. Theoretical models were used to obtain the maximum packing or volume fraction (ϕ max ) of randomly oriented short fibers and its relationship with the mechanical parameters. A higher elastic modulus and tensile strength were observed when the fiber content was increased in the composite at a fixed aspect ratio (length/diameter = 2.8). Material selection charts showed that SSFCs with a fiber concentration of 20 wt % had a higher reinforcement effect at ϕ max , as was predicted through theoretical models. Nevertheless, SSFCs with a fiber concentration of 7 wt % presented optimum reinforcement because it resulted in the strongest and lightest composite material. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47821.