In the present study, the suitability of various chemical treatments to improve the performance of jute fibers (JFs) filled natural rubber (NR) composites was explored. The surface of JFs was modified by three different surface treatments, namely, alkali treatment, combined alkali/stearic acid treatment and combined alkali/silane treatment. Surface modified JFs were characterized by X-ray diffraction (XRD) pattern, Fourier transform infrared (FTIR) spectroscopy and field emission scanning electron microscopy (FESEM). The reinforcing effect of untreated and surface treated JFs in NR composites was comparatively evaluated in terms of cure, mechanical, morphological and thermal properties. Combined alkali/silane treated JFs filled NR composite showed considerably higher torque difference, tensile modulus, hardness and tensile strength as compared to either untreated or other surface treated JFs filled NR systems. A crosslink density measurement suggested effective rubber-fibers interaction in combined alkali/silane treated JFs filled NR composite. Morphological analysis confirmed the improvement in the interfacial bonding between NR matrix and JFs due to combined alkali/silane treatment allowing an efficient "stress-transfer" mechanism. As a whole, combined alkali/silane treatment was found to be most efficient surface treatment method to develop strong interfacial adhesion between NR matrix and JFs.
Keywords: mechanical properties; rubber; scanning electron microscopy; short jute fibers; surface treatments.