Transport properties of polyester composite reinforced with treated sisal fibers

Thermal conductivity, diffusivity, relative permittivity, specific heat, and tensile properties of sisal/polyester composites were investigated as a function of fiber volume fraction and fiber surface modification. The composites were prepared by resin transfer molding (RTM) technique. Sisal fibers were subjected to various chemical and physical modifications such as mercerization, heating at 100 degrees C, permanganate treatment, benzoylation, and silanization to improve the interfacial bonding with matrix. All treatments used in this study improved the relative permittivity, tensile strength, Young's modulus, and reduced the elongation at break. The use of NaOH and silane treatments decreased the thermal conductivity. Beside these, a comparison between dielectric, mechanical, and thermal behaviors of the composites was reported in this paper. A linear dependence of the relative variation of dielectric permittivity, Young's modulus, and thermal conductivity was also shown for untreated systems.