Energy efficient production of nano-fibrillated cellulose (NFC) from cotton linters by tri-disc refining and its characterization

Abstract

In this work, nano-fibrillated cellulose (NFC) with a diameter in the range of 50 to 200 nm was prepared from bleached cotton linter pulp by a combination of enzymatic and mechanical processes. To circumvent the problem of high energy consumption during mechanical processes, pretreatment with cellulase enzyme was carried out and achieved 27% energy reduction. A custom-designed recirculation setup was used with a Tri-Disc Refiner for repeated refining of the pulp. The crystallinity of the raw material (83.3%) was reduced to 81.0% in the final product (NFC) due to shearing and cutting actions involved in the processing steps (pulping, beating and refining), as could be assessed by XRDanalysis. The stages of fibrillation and their corresponding size reduction were demonstrated by SEM analysis. The resultant NFC has potential applications in papers, electronics, pharmaceuticals, fuel cells and fertilizers.