Degradation study of nanocellulose crystal (NCC) and nanocellulose fibre (NCF) - filled polyhydroxyalkanoate/natural rubber (PHA/NR) - based nanocomposites

Abstract This study investigates the effects of nanocellulose crystal (NCC) and nanocellulose fibre (NCF) additives on the thermal ageing resistance and biodegradation behavior of poly(3-hydroxybutyrate-co-3-hydroxyvalerate)/natural rubber (PHBV/NR) blends. Nanocomposites containing 0-5 wt.% of NCC or NCF were prepared and subjected to thermal ageing and soil burial tests. Thermal ageing results showed that both NCC and NCF enhanced the pre-ageing mechanical properties of PHBV/NR blends, with NCC providing slightly superior performance. Soil burial tests revealed that nanocellulose additives significantly improved the biodegradability of the blends, with NCF showing more pronounced effects at lower concentrations. FTIR analysis indicated subtle changes in chemical structure during degradation, while optical microscopy analyses demonstrated significant morphological changes in nanocellulose-containing samples after soil burial. The contact angle results show that NCFs significantly increase hydrophilicity because of their fibrous morphology and network formation. The optimal nanocellulose concentration for enhanced biodegradability was found to be around 3% for both types, with PHBV/NR/NCF3 exhibiting the highest overall weight loss of 27.0% after 42 days. This study highlights the potential of nanocellulose additives in developing biodegradable polymer nanocomposites with tailored degradation profiles and improved long-term performance for applications requiring thermal stability and controlled biodegradability.