Cellulose nanocrystals derived from wastepaper as an eco-friendly thermal insulation material

The demand for thermally insulating, ultraviolet (UV) shielding materials derived from natural resources to meet sustainable societal development is of utmost importance due to increased energy consumption and environmental concerns. Cellulose nanocrystals (CNCs) are currently regarded as one of the most intriguing green nanomaterials with tremendous application potential, owing to their availability, renewability, biodegradability and intrinsic biocompatibility. This work presents an efficient approach for the eco-friendly utilization of wastepaper (WP) through the extraction of CNCs from it. Also, the practical applicability of CNCs is explored through the investigation of thermal properties such as thermal diffusivity and thermal conductivity via a dual-beam mode mismatched thermal lensing (TL). The thermal diffusivity values of the dispersion of CNCs in water and ethanol are found to be 5.741 × 10^–8 to 4.271 × 10^–8 m²s⁻¹ and 7.909 × 10^–8 to 5.507 × 10^–8 m²s⁻¹, respectively. The results of the current study are expected to pave a new path for the development of forthcoming thermal insulation materials derived from environmentally benign and sustainable CNCs.