Cellulose nanocrystal filled synthetic rubber: Sustainable production, environmental assessment and end-of-life biodegradation by polyphagous pests

Plastic and rubber productions have reached staggering levels, leading to environmental concerns and accumulation of microplastics (MPs) rising in ecosystems. Rubber tires, a major source of MPs, pose further challenges due to excessive use of carbon black (CB) nanofillers in their manufacturing process, stresses on adding the element of sustainability to these products. This study emphasizes the production of bio-based cellulose nanocrystals (CNC) filled synthetic rubber with sustainability assessment through life cycle assessment (LCA). It investigates the end-of-life (EOL) biodegradation potentials of rubber waste using a polyphagous pest, fall armyworm (FAW) (Spodoptera frugiperda). The results revealed that the production of CNC filled rubber demonstrate enhanced modulus compared to CB nanofillers, while requires substantial resource consumption, impacting abiotic resource depletion–fossil fuels (ADPf), freshwater ecotoxicity (CTUe), global warming potential (GWP), particulate matter (PM) and other impact categories. Emissions associated with CNC filled rubber during EOL phase are comparatively lower than CB, rendering CNC based rubbers a potentially viable choice from an environmental sustainability perspective. EOL pest biodegradation of CNC filled rubber showed negligible to no discernible physiological effects, potentially attributed to presence of a diverse gut microbiota community in FAW (S. frugiperda). These findings highlight the relationship between physiochemical properties and CNC biodegradability in rubber, aiding the development of sustainable EOL strategies for rubber waste management.