Characterization of Bio-Based Natural Rubber Nanocomposites Made from Agro-Industrial Byproducts

Agricultural and industrial food processing byproducts are generated in large quantities, yet most of them lack of a valuable application and are treated as wastes that require costly disposal.   In previous research, we successfully made composites of natural rubber containing waste-derived fillers as partial and complete replacements of petroleum-derived Carbon Black N330, all with 35 phr (parts per hundred rubber) combined loading.  The four wastes, eggshells, carbon fly ash, processing tomato peels and guayule bagasse, were prepared with macro (38-300 µm diameter) and micro (1-38 µm diameter) particle size distributions.  These materials not only are generated in very high volumes, which ensure their continuous availability, but also possess varied and complex compositions, which allow composite properties to be tailored and novel composite materials to be made.  Most of the composites with microsized fillers had excellent properties up to a 57: 43 ratio of filler to carbon black.

In this paper, we report on the performance of rubber composites loaded with the waste-derived fillers prepared at nano-scale.  Nano-fillers generally generate better physical properties in composites than larger fillers.  The effect of nano-filler type and loading on mechanical, dynamic and thermal properties were analyzed and compared with previous results using micro and macro fillers. Agro-industrial byproducts are a potentially important source of fillers that can improve the sustainability of rubber products and reduce dependency on non-renewable resources.