"Preparation of highly charged cellulose nanofibrils using high-pressur" by Cuihua Tian, Jianan Yi et al.

Faculty Publications

Title

Preparation of highly charged cellulose nanofibrils using high-pressure homogenization coupled with strong acid hydrolysis pretreatments

Authors

Cuihua Tian, School of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha, Hunan 410004, China.
Jianan Yi, School of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha, Hunan 410004, China.
Yiqiang Wu, School of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha, Hunan 410004, China. Electronic address: wuyq0506@126.com.
Qinglin Wu, School of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha, Hunan 410004, China; School of Renewable Natural Resources, Louisiana State University Agricultural Center, Baton Rouge, LA 70803, USA.
Yan Qing, School of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha, Hunan 410004, China. Electronic address: qingyan0429@163.com.
Lijun Wang, School of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha, Hunan 410004, China.

Document Type

Article

Publication Date

1-20-2016

Abstract

Cellulose nanofibrils (CNFs) are attracting much attention for the advantages of excellent mechanical strength, good optical transparency, and high surface area. An eco-friendly and energy-saving method was created in this work to produce highly negative charged CNFs using high-pressure mechanical defibrillation coupled with strong acid hydrolysis pretreatments. The morphological development, zeta potential, crystal structure, chemical composition and thermal degradation behavior of the resultant materials were evaluated by transmission electron microscopy (TEM), zeta potential analysis, X-ray diffraction (XRD), Fourier transform infrared spectrometry (FTIR), and thermogravimetric analysis (TGA). These CNFs were fully separated, surface-charged, and highly entangled. They showed a large fiber aspect ratio compared to traditional cellulose nanocrystrals that are produced by strong acid hydrolysis. Compared to hydrochloric acid hydrolysis, the CNFs produced by sulfuric acid pretreatments were completely defibrillated and presented stable suspensions (or gels) even at low fiber content. On the other hand, CNFs pretreated by hydrochloric acid hydrolysis trended to aggregate because of the absence of surface charge. The crystallinity index (CI) of CNFs decreased because of mechanical defibrillation, and then increased dramatically with increased sulfuric acid concentration and reaction time. FTIR analysis showed that the C-O-SO3 group was introduced on the surfaces of CNFs during sulfuric acid hydrolysis. These sulfate groups accelerated the thermal degradation of CNFs, which occurred at lower temperature than wood pulp, indicating that the thermal stability of sulfuric acid hydrolyzed CNFs was decreased. The temperature of the maximum decomposition rate (Tmax) and the maximum weight-loss rates (MWLRmax) were much lower than for wood pulp because of the retardant effect of sulfuric acid during the combustion of CNFs. By contrast, the CNFs treated with hydrochloric acid had better thermal stability, because no functional groups were introduced on the surface.

Publication Source (Journal or Book title)

Carbohydrate polymers

First Page

485

Last Page

Recommended Citation

Tian, C., Yi, J., Wu, Y., Wu, Q., Qing, Y., & Wang, L. (2016). Preparation of highly charged cellulose nanofibrils using high-pressure homogenization coupled with strong acid hydrolysis pretreatments. Carbohydrate polymers, 136, 485-92. https://doi.org/10.1016/j.carbpol.2015.09.055

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