Bionanocomposites based on natural rubber and cellulose nanofibrils from arecanut husk: Rheological, mechanical and thermal characterizations

Cellulose nanofibrils with a substantial aspect ratio (100–150) were isolated from an abundant agricultural waste, arecanut husk. These cellulose nanofibrils were incorporated into natural rubber (NR) latex and the resulting composites were investigated for rheological, dynamic mechanical, physical and thermal properties. Rheological and dynamic mechanical analysis of the composites were carried out as a function of fibre content, frequency and temperature using Rubber Process Analyser (RPA) and Dynamic Mechanical Analyser (DMA). All the systems registered rise in elastic response with increase in frequency. RPA studies showed that the nanocellulose fibrils had a profound influence on the rheological behaviour of the composites. The rheological percolation threshold of the composites was obtained to be between 2 to 4 phr. The dispersion of nanofibrils in the composites was investigated using Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM). An extensive network formation in the NR matrix, credited to the higher aspect ratio of nanofibrils, imparted the composites with improved mechanical properties. Cellulose nanofibrils do not inflict any detrimental effect on the thermal profiles of the composites. Graphical abstract