Cellulose nanocrystals from native and mercerized cotton

Abstract

Nanocelluloses occur under various crystalline forms that are being selectively used for a wide variety of high performance materials. In the present work, cellulose fibers (CF-I) were mercerized by alkaline treatment (CF-II) without molar mass variation (560 000 g/mol) and both were acid hydrolyzed, forming cellulose nanocrystals in native (CNC-I) and mercerized (CNC-II) forms. This work establishes detailed characterization of these two nanoparticles morphology (light and neutron scattering, TEM, AFM), surface chemistry (zetametry and surface charge), crystallinity (XRD, 13 C NMR), and average molar mass coupled to chromatographic technics (SEC-MALLS-RI, A4F-MALLS-RI), evidencing variations in packing of the crystalline domains. The crystal size of CNC-II is reduced by half compared to CNC-I, with molar masses of individual chains of 41 000 g/mol and 22 000 g/mol for CNC-I and CNC-II respectively, whereas the same charged surface chemistry is measured. This fundamental analysis may give insight to new applicative development.

Edge-On (Cellulose II) and Face-On (Cellulose I) Adsorption of Cellulose Nanocrystals at the Oil–Water Interface: A Combined Entropic and Enthalpic Process

“…Once the fibers hydrolyzed with sulfuric acid, CNC-I and CNC-II showed identical surface charge density, but the CNC-II recovered were shorter in length and had smaller particle molar masses as well as molar masses of dissolved individual cellulosic chains. 23,24 The lateral dimension of CNC-II was similar to that of CNC-I but the thickness was about half that of CNC-I.…”

Chiral Self-Assembly Behavior of Carboxylated Cellulose Nanocrystals Isolated by Recyclable Oxalic Acid from Degreasing Cotton

“…Cellulose nanocrystals (CNCs), a biosourced nanomaterial produced from cellulose, have gained increasing attention in recent decade due to its particular physicochemical properties. − A fascinating characteristic of the CNCs is that it can form a chiral nematic (also called cholesteric) lyotropic liquid crystal phase spontaneously above a critical concentration in water, , making it a valuable material applied in sensing, anticounterfeiting, or decoration …”

Synthetic Nanocelluloses Fluorescently Responsible to Enzymatic Degradation

“…Here, the crystallinity index (CI) values of the cellulose moieties for CEL-C 8 and CEL-C 6 assemblies in a powdery state were newly measured to be 80 and 82%, respectively, by 13 C cross-polarization-magic angle spinning (CP-MAS) nuclear magnetic resonance (NMR) spectroscopy (Figure S1). These values were comparable to those of naturally derived nanocelluloses such as nanofibrillated cellulose, bacterial cellulose, and cellulose nanocrystals. ,, Consequently, the CEL-C 8 and CEL-C 6 assemblies show similar characteristics to each other (Table S1 and Figure S2 for morphologies).…”

“…These values were comparable to those of naturally derived nanocelluloses such as nanofibrillated cellulose, bacterial cellulose, and cellulose nanocrystals. 13,53,54 Consequently, the CEL-C 8 and CEL-C 6 assemblies show similar characteristics to each other (Table S1 and Figure S2 for morphologies).…”

“…CP-MAS NMR spectra for CEL-C 8 and CEL-C 6 assemblies in a powdery state were obtained using a Bruker Avance III 600 MHz spectrometer at 25 °C. The CI values of the cellulose moieties in the assemblies were estimated by deconvolution of the C4 signals of glucose units at approximately 80–95 ppm, according to a previous study …”