Effect of fiber loading and chemical treatments on thermophysical properties of banana fiber/polypropylene commingled composite materials

A periodical method was used to estimate the thermal conductivity, thermal diffusivity and specific heat of polypropylene (PP)/banana fiber commingled composites at room temperature. These thermophysical properties of the composites were investigated as a function of the banana fiber loading and for different chemical treatments given to the banana fiber. It was found that the thermal conductivity and thermal diffusivity of the composites decrease with fiber loading. But the specific heat of the fiber composites does not show a significant change. The use of chemically treated banana fibers caused an increase in the thermophysical properties of the composites irrespective of the nature of the chemical treatments. Of the various treatments given, the benzoylated fiber composites showed the highest values of thermal conductivity and thermal diffusivity. It was also observed that NaOH concentration has an influence on the thermophysical properties of the composites. A 10% NaOH treated banana fiber composites showed better thermophysical properties than 2% NaOH treated banana fiber composites. The use of a theoretical series conduction model allowed estimating the transverse thermal conductivity of untreated banana fiber composites (kf = 0.1166 ± 0.0001 W m−1 K−1).