Influence of polarity parameters on the mechanical properties of composites from polypropylene fiber and short banana fiber

Polypropylene (PP)/banana fiber (BF) composites were prepared from PP fiber and short banana fiber. BF surfaces were modified chemically to bring about improved interfacial interaction. The polarity parameters of the chemically modified BF were investigated using the solvatochromic technique. The empirical Kamlet–Taft solvatochromic polarity parameters such as hydrogen bond donating ability HBD or acidity (α), hydrogen bond accepting ability HBA or basicity (β), the dipolarity (π*), Gutman acceptor number (AN), Reichardts ET (30) values for the chemically modified BF was determined. It was found that the polarity of the BF was decreased after the chemical treatment. The fiber/matrix interactions were found to depend on the polarity of the BF. The improved fiber/matrix interaction was evident from the enhanced tensile and flexural properties. The lower impact properties of the treated fiber composites further point to the improved fiber/matrix interaction. The diameter of the chemically modified BF was measured using an optical microscope. Scanning electron microscopy studies revealed the changes of the surface morphology of the fibers after the chemical treatments.