Ionic Liquids Grafted Cellulose Nanocrystals for High-Strength and Toughness PVA Nanocomposite

Abstract

The surface functionalization of cellulose nanocrystals (CNCs) is of significant importance for promoting its diverse applications. However, the efficient strategy reported so far for cation functionalization of CNCs remains limited owing to the electrostatic attraction between cationic modifiers and electronegative CNCs. Herein, a cationized CNC (CNC-LA-IL) has been successfully prepared in aqueous media by grafting the [VBIm]­[BF4], a kind of ionic liquid (IL), on the surface of a sulfated CNC using lactic acid (LA) as a linker molecule. This surface functionalization not only converts the negative charge of CNC suspensions to a positive charge (zeta potential reversed from −35 to +40 mV) but also leads to enhanced thermal stability and redispersibility of the dried CNC. To examine the reinforcing effect of IL-modified CNCs, poly­(vinyl alcohol) (PVA)/CNC-LA-IL nanocomposite films were further prepared by the solution casting method. To one’s surprise, the as-prepared PVA/CNC-LA-IL films exhibit extraordinary improvement in both the tensile strength (92%) and the toughness (166%) with only a 0.3 wt % CNC loading. This study provides a green and facile method to achieve ionic liquids grafted CNCs for high-performance nanocomposites.

An Efficient and Sustainable Approach to Prepare Carboxylated Cellulose Nanocrystals for Rubber Reinforcement Featuring Dual Crosslinking Networks

“…1a, in the FTIR spectra of CNC-CA, there is a new band appeared at 1725 cm -1 which corresponds to the C = O vibration from the ester groups of the carboxylic acids (Yu et al 2014). Compared with the spectrum of CNC-OSO 3 H, the band at 812 cm -1 which corresponds to C-O-S vibration disappeared in CNC-CA (Wang et al 2020). Those evidences suggest that the CA have been grafted successfully on CNC-OSO 3 H and most of the sulfonate on the surface of CNC-OSO 3 H was removed during the modi cation process.…”

“…CNC-OSO H was extracted from CLP via sulfuric acid hydrolysis as described in our previous work (Wang et al 2020). In brief, raw CLP was rst immersed in 4 wt% NaOH solution for 24 h at room temperature.…”

Recent advances in polysaccharide‐based hydrogels for synthesis and applications

“…Recently, free radical polymerization is used to graft poly (ionic liquid) on CNCs, superior mechanical PVA‐based hydrogels can be obtained upon CNC loading via ionic interaction and hydrogen bonding. [ 58 ] More specifically, grafting charged monomers via advanced polymerization techniques resulted in cellulose with controlled functionality and structures. [ 23 ] The second‐guest polymer was prepared via surface‐initiated atom transfer radical polymerization (SI‐ATRP) of monomers, dimethylaminoethyl methacrylate (DMAEMA) and napththyl‐functionalized methacrylate (NpMA), yielding naphthyl‐functionalized polymer brushes (CNC‐g‐P(DMAEMA‐r‐NpMA)).…”

“…PVA is one of the most significant synthetic polymers due to its excellent strength and flexibility, superior oxygen barrier, as well as ease film-forming characteristics, which has been widely exploited to prepare cellulosebased composite hydrogels. [57][58][59] Cyclic freezing-thawing process is usually used to achieve the gelation of PVA aqueous solution derives from the phase separation. Enhanced mechanical performances of PVA/CNC hydrogels arising from the synergistic effect of hydrogen bonding between PVA and CNCs as well as reinforcement of rigid rod-like CNCs was reported.…”

Flexible Cellulose-Based Assembled with PEDOT: PSS Electrodes for ECG Monitoring

“…2b) that 438 cm − 1 , 570 cm − 1 , 984 cm − 1 , 1255 cm − 1 and 1424 cm − 1 peaks belong to the C-O-C deformation peak of PEDOT, the symmetrical C-S-C deformation peak, the ring deformation peak of oxyacetylene(Nur A fah et al 2016), and the stretching deformation of Cα-Cα inner ring, and the symmetric stretching deformation of Cα-Cβ, respectively (Jian et al 2018). The characteristic peak intensity in the range of 2500 cm − 1 to 3000 cm − 1 is regarded as the characteristic peak intensity of PVA, and the stretching vibration excitation of methylene (-CH 2 ) occurs at 2840 cm − 1 (Li et al 2020).…”