In this study microcrystalline cellulose (MCC) was oxidized by 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated oxidation. The treated cellulose slurry was mechanically homogenized to form a transparent dispersion which consisted of individual cellulose nanofibers with uniform widths of 3–4 nm. Bio-nanocomposite films were then prepared from a polyvinyl alcohol (PVA)-chitosan (CS) polymeric blend with different TEMPO-oxidized cellulose nanofiber (TOCN) contents (0, 0.5, 1.0 and 1.5 wt %) via the solution casting method. The characterizations of pure PVA/CS and PVA/CS/TOCN films were performed in terms of field emission scanning electron microscopy (FESEM), tensile tests, thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). The results from FESEM analysis justified that low loading levels of TOCNs were dispersed uniformly and homogeneously in the PVA-CS blend matrix. The tensile strength and thermal stability of the films were increased with the increased loading levels of TOCNs to a maximum level. The thermal study indicated a slight improvement of the thermal stability upon the reinforcement of TOCNs. As evidenced by the FTIR and XRD, PVA and CS were considered miscible and compatible owing to hydrogen bonding interaction. These analyses also revealed the good dispersion of TOCNs within the PVA/CS polymer matrix. The improved properties due to the reinforcement of TOCNs can be highly beneficial in numerous applications.

Nanotechnology provides useful insights into the behavioural properties of materials from the nanoscale point of view, enabling researchers to develop new materials that were previously inconceivable. Cellulose is an ideal candidate for nanomaterial for nanotechnology because of its nanofibrillar structure, abundance, renewability, biodegradability and eco-friendly nature. Nanocrystalline cellulose materials have become the focus many studies related to these materials and their applications. This review summarises the current knowledge on the field of nanomaterials, focussing mainly on the rheological behaviour of polymer nanocomposites embedded with nanocrystalline cellulose. This review will enable better understanding of the use of nanocrystalline cellulose for the development and applications of cellulose nanocrystal-based nanocomposites.

In the present study, the feasibility and the practicability of two different approaches to the individualization of microfibrillated celluloses (MFCs) from oil palm empty fruit bunches were evaluated. Some properties of MFCs prepared by ammonium persulfate (APS) oxidation were investigated and compared with those extracted using sulfuric acid hydrolysis. Fourier transform infrared observation demonstrated that almost all the hemicelluloses and lignin were effectively removed after the sulfuric acid hydrolysis, which was substantiated by the disappearance of the characteristic peaks of these two noncellulosic components at 1735 and 1508 cm−1, respectively. However, a peak at 1735 cm−1 was observed in the spectrum of APS-oxidized MFCs because the products prepared by this treatment are stabilized by carboxyl groups instead of sulfate half-ester groups, which introduced by sulfuric acid. Furthermore, X-ray diffractograms of MFCs revealed the decrease in crystallinity after sulfuric acid hydrolysis but remained similar after APS oxidation. Thermogravimetric analysis was employed to determine the thermal stability of the treated fibers. In addition, the morphologies and diameters of MFCs were determined by field-emission scanning electron microscopy. MFCs formed by these two different techniques exhibited long and network-like fibrils with widths ranging from 8 to 40 nm. UV-Vis spectroscopy was used to monitor the optical transmittance of the nanocellulose suspensions.

No abstract

A poorly water-soluble anticancer drug, curcumin was loaded in to cellulose nanocrystals by dissolving it in a commonly used nonionic surfactant medium. Results showed that the drug loading capacity of nanocellulose increased with increasing the surfactant concentration of the medium.The drug loading capacity of nanocellulose in surfactant medium was significantly higher (7.73mg/g) when compared to the drug loading capacity (3.35mg/g) in methanolic medium. The nanocellulose drug loaded in surfactant medium (TW/CNC) showed higher drug release compared to the nanocellulose drug loaded in methanolic medium (METH/CNC). It was 8.99 mg/L for TW/CNC and 2.65 mg/L for METH/CNC in simulated gastric fluid. Due to the increased stability of curcumin in acidic medium, all the nanoparticles showed higher drug release in simulated gastric fluid compared to phosphate buffered saline solution. The maximum dissolution of curcumin was 2.13 mg/mL in distilled water containing 4% (w/v) of surfactant.UV-visible spectra revealed that the curcumin retained its chemical activity after in vitro release.From these findings, it is believed that the incorporation of curcumin into nanocellulose in surfactant medium provides a promising approach for delivery of curcumin to stomach and upper intestinal tract.