Properties of natural rubber reinforced with cellulose nanofibers based on fiber diameter distribution as estimated by differential centrifugal sedimentation

Abstract Cellulose nanofibers (CNFs) with different degrees of fibrillation are prepared by the mechanical fibrillation of kraft pulp using wet disk milling, and dispersions of the prepared CNFs were subjected to differential centrifugal sedimentation (DCS) in order to estimate the diameter distributions of the CNFs. The low-fibrillated CNFs (fiber diameter ( d ): >10 μm) had a weak reinforcing effect on natural rubber (NR), while the medium-fibrillated CNFs ( d : 0.1–10 μm) dramatically improve the initial modulus and decrease the elongation at break. The high-fibrillated CNFs ( d :