Preparation and characterization of poly(butylene succinate) bionanocomposites reinforced with cellulose nanofiber extracted from Helicteres isora plant

Isora nanofibers (INF) were produced by a combined thermal-chemical-mechanical method from Helicteres isora plant. The resulting fibers were analyzed using transmission electron microscopy and scanning electron microscopy, which showed a network-like structure with a length of 600 nm, width of 50 nm and an aspect ratio of 12. Fourier transform infrared spectroscopy indicated that chemical treatments progressively removed noncellulosic constituents. X-ray diffraction analysis revealed that crystallinity increased with successive chemical treatments. Using the synthesized isora nanofibers, poly(butylene succinate) (PBS)-based biodegradable nanocomposites were prepared. The nanocomposites were processed using a Brabender twin-screw compounder and an injection molding machine. Effects of INF on the mechanical properties of nanocomposites were investigated. Tensile and flexural moduli of PBS-INF nanocomposites showed an increase with increase in INF content owing to the network formation of the nanofibers in the PBS matrix, whereas toughness and strain-at-break exhibited the opposite trend. Tensile and flexural strengths showed an increase up to 1.5 phr of INF loading, beyond which they were observed to decline owing to agglomeration of INF. Theoretically predicted tensile strength and Young's modulus were found to increase with INF content; however, there existed a mismatch between theoretical predictions and experimental observations.