Complete nanofibrillation of cellulose prepared by phosphorylation

Direct sulfation of cellulose fibers using a reactive deep eutectic solvent to produce highly charged cellulose nanofibers

“…The transparency of SCNF is higher than those observed with CNF produced by TEMPO and sequential periodate-chlorite oxidations (Sirviö et al 2014), and is close to the values obtained from the CNCs produced using sequential periodate-chlorite oxidation (Sirviö et al 2015b). Previously, over 95% total transmittance was obtained from CNF produced from phosphorylated cellulose (0.2% solution in water) (Noguchi et al 2017). Moreover, highly charged (3.8 mmol/g) succinylated CNF exhibited a transmittance of 97% at a wavelength of 600 nm (Sehaqui et al 2017), similar to the results obtained here (98%).…”

“…Moreover, the use of powder-like cellulose, such as microcrystalline cellulose, is assumed to enable a more efficient mixing and therefore a more even reaction. On the industrial scale, one plausible method to produce sulfonated cellulose using DES is the one proposed previously for the phosphorylation of cellulose using aqueous ammonium dihydrogen phosphate (Noguchi et al 2017). A pre-prepared dry pulp sheet is first immersed in a solvent (i.e., DES), excess solvent is removed, and the sheet is allowed to react at the desired reaction temperature.…”

Nanocellulose-stabilized Pickering emulsions and their applications

“…Nanocelluloses are typically prepared through mechanical disintegration of bundles of cellulose microfibrils. The width, length, and surface properties of nanocellulose can be controlled by changes in cellulose sources and pretreatment: mechanical treatment only [ 44–47 ] or with pretreatment, such as acid hydrolysis [ 48, 49 ], 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-mediated oxidation [ 50–52 ], carboxymethylation [ 53 ], phosphorylation [ 54, 55 ], and enzymatic hydrolysis [ 56–59 ]. Given that the original crystal structure of cellulose microfibrils [ 60–62 ] remains intact even after preparation, nanocelluloses have high modulus (130–150 GPa) [ 63–65 ] and strength (2–6 GPa) [ 66, 67 ] and low coefficient of thermal expansion (4–6 ppm K −1 ) [ 68, 69 ] along the c -axis.…”

Isolation and characterization of cellulose nanofibers from aspen wood using derivatizing and non-derivatizing pretreatments

“…Improved processes for isolating cellulose nanofibers (CNFs) from recalcitrant wood celluloses have received increased attention recently. The reported methods include different chemical pretreatments prior to mechanical disintegration, such as TEMPOmediated oxidation (Saito et al 2007(Saito et al , 2009, enzymatic hydrolysis (Henriksson et al 2007), etherification (Wågberg et al 2008), periodate and chlorite oxidation (Liimatainen et al 2012), ionic liquids (Li et al 2012), deep eutectic solvents (Li et al 2017), and phosphorylation (Noguchi et al 2017), to name a few. Aside from significant energy consumption reduction, enhanced degree of fibrillation is often associated, where nanofibers resembling the characteristic individual cellulose micro-or elementary fibrils are attainable.…”