Recently, researchers from Institute of Bast Fiber Crops, Chinese Academy of Agricultural Sciences (IBFC, CAAS) and Central South University (CSU）have revealed the action mechanism of pectin on the dissociation of ramie cell walls and redispersion of its resulting nanocellulose, whcih provides a new theoretical guidance for the large-scale production and application of nanocellulose, and also presents new ideas for the high-value utilization of all components of biomass.
Cellulose is the most abundant biopolymer on earth, with an estimated annual output of 75 billion tons. Cellulose nanofibrils (CNFs) are cellulose fibrils with widths on a nanoscale and lengths on a micrometer scale. Due to its renewability, abundance, high mechanical properties, and high structural/chemical tunability, CNFs have exhibited great potential in diverse value-added applications such as nanocomposite, packaging, functional food, biomedicine, sensing, energy storage, electronics, catalysis, and environmental remediation.
In this study, a series of pretreatment methods (pectin extraction) were employed to prepare CNFs with different pectin composition and contents from ramie fibers. The comprehensive effects of residualpectin on the final properties of CNFs were investigated. The residual pectin did not have a significant effect onthe size distribution of the obtained CNFs. While the presence of pectin led to higher zeta potential value,improved dispersion stability and enhanced storage modulus of the CNF dispersion, with the sodium carbonateextraction method showing the greatest impact. The possible mechanism for enhanced dispersion stability ofCNFs is the formationofself-assembled hierarchical pectin-hemicellulose/lignin-cellulose nanostructures, offeringabundant electrostatic repulsion and steric hindrance between the nanoparticles. This work providesguidelines for the tailored production of CNFs to meet the requirements for different applications.
The research was supported by the Science and Technology Innovation Project of the CAAS and the Youth Program of the National Natural Science Foundation of China.
The study entitled “Effects of residual pectin composition and content on the properties of cellulose nanofibrils from ramie fibers” has been published online in Carbohydrate Polymers and can be accessed through the following link: https://doi.org/10.1016/j.carbpol.2022. 120112.
Fig. Structure of the pectic polysaccharide homogalacturonan and possiblemechanisms behind the effect of
residual pectin on the dispersion stability of CNFs.
