Use Of Nanocrystalline Cellulose Research Articles

Effects of nanocrystalline cellulose on the micro-creep properties of phenol formaldehyde resin

The use of nanocrystalline cellulose (NCC) has become increasingly prevalent in recent years, with limited studies on the the time-dependent characteristics of wood-adhesive composite reinforced by it. To analyze the viscoelasticity of control phenol formaldehyde (PF) resin and wood-resin composites added with three types of NCC, the micro-creep properties of control phenol formaldehyde (PF) resin and PF resin with cellulose nanofibrils (CNF), cellulose microfibrils (CMF), and cellulose nanocrystals (CNC) were investigated by nanoindentation (NI). The sample creep curves proved that adding CNC, CMF, and CNF into the PF resin remarkably impacted the creep properties of the wood-resin sample interface. The cured resin sample had the lowest strength and the most deformation, and the pure wood sample performed slightly better. Among the three NCC-added wood-resin samples, the CNF-added wood-resin sample has the least deformation in the same load and the least permanent deformation after unloading followed by CMF-added and CNC-added wood-resin samples. In the derivative of creep curve function, the depth tendency of CNC-added and CNF-added wood-resin samples showed a gently increasing slope with time in contrast to CMF-added ones. Furthermore, scanning probe microscopy (SPM) images supported that PF resin had filled up the pores of the wood microstructures and strengthened the wood-resin sample in the company of NCC, which was then able to carry the load.

Incorporation of thermally labile additives in carbon membrane development for superior gas permeation performance

Incorporating thermally labile polymer additives into carbon membrane development is highly practical due to its process simplicity and effective approach. In this study, different polymer composition of thermally labile additives such as polyvinylpyrrolidone (PVP), microcrystalline cellulose (MCC) and nanocrystalline cellulose (NCC) were introduced into the BTDA-TDI/MDI (P84-copolyimide) polymer solution. The P84-copolyimide based carbon tubular membranes were fabricated using dip-coating method and characterized in terms of its thermal stability, structural morphology and gas permeation properties. Initially, the NCC was introduced as a pore performing agent in the carbon membrane fabrication for carbon dioxide (CO2) separation. Our finding indicated that the use of NCC as pore performing agent significantly promoted an increment of pore structure channel in carbon membrane. As a result, the high permeance as well as high selectivity was demonstrated in this study. Pure gas permeation tests were performed using CO2, CH4, O2 and N2 at room temperature. The increment of both gas permeance and selectivity were observed in the NCC-containing carbon membranes prepared with a composition of 7 wt%. The promising CO2/CH4 selectivity of 68.23 ± 3.27, CO2/N2 selectivity of 66.32 ± 2.18 and O2/N2 selectivity of 9.29 ± 2.54 with respect to neat carbon membrane were presented. Thus, upon further investigation, the potential of NCC as thermally labile additive in carbon membrane was assured.

N-doped mesoporous TiO2 nanoparticles synthesized by using biological renewable nanocrystalline cellulose as template for the degradation of pollutants under visible and sun light

Yellow-colored N-doped mesoporous TiO2 photocatalyst (TiO2-NT) with visible-light response was prepared by a hydrolysis–precipitation method at different urea contents with the use of nanocrystalline cellulose (NCC) as template. The photocatalytic activity was investigated through the degradation of phenol, nitrobenzene, and methyl orange (MO) under artificial visible and sun light irradiation. X-ray photoelectron spectroscopy (XPS), UV–Vis diffuse spectroscopy (DRS), X-ray diffraction (XRD), thermogravimetry–differential thermal analysis (TG/DSC), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and N2 adsorption–desorption isotherms were used for catalyst characterization. The results showed that NCC-templated TiO2 with a suitable N-doping content (TiO2-NT) exhibited higher activity under visible and sun light irradiation than N-doped TiO2 synthesized without NCC template (TiO2-N). Affected by the hydroxyl groups of NCC macromolecule and the Ti precursor, the growth and aggregation of TiO2 precursor before calcination were inhibited. The NCC template led to high dispersion, small grain size, and high specific surface area of TiO2-NT. Nitrogen doping was proposed to adjust band gap and electrical properties of TiO2 by establishing acceptor defect. N-doped TiO2 with the intrinsic donor defect of oxygen vacancy and the nitrogen-to-oxygen acceptor defect could be excited by visible irradiation for efficient pollutant degradation.

Rheological properties of cellulose nanocrystal-embedded polymer composites: a review

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.

Adsorption and Desorption of Methylene Blue on Porous Carbon Monoliths and Nanocrystalline Cellulose

The dynamic batch adsorption of methylene blue (MB), a widely used and toxic dye, onto nanocrystalline cellulose (NCC) and crushed powder of carbon monolith (CM) was investigated using the pseudo-first- and -second-order kinetics. CM outperformed NCC with a maximum capacity of 127 mg/g compared to 101 mg/g for NCC. The Langmuir isotherm model was applicable for describing the binding data for MB on CM and NCC, indicating the homogeneous surface of these two materials. The Gibbs free energy of -15.22 kJ/mol estimated for CM unravelled the spontaneous nature of this adsorbent for MB, appreciably faster than the use of NCC (-4.47 kJ/mol). Both pH and temperature exhibited only a modest effect on the adsorption of MB onto CM. The desorption of MB from CM using acetonitrile was very effective with more than 94 % of MB desorbed from CM within 10 min to allow the reusability of this porous carbon material. In contrast, acetonitrile was less effective than ethanol in desorbing MB from NCC. The two solvents were incapable of completely desorbing MB on commercial granular coal-derived activated carbon.

The use of nanocrystalline cellulose for the binding and controlled release of drugs

The objective of this work was to investigate the use of nanocrystalline cellulose (NCC) as a drug delivery excipient. NCC crystallites, prepared by an acid hydrolysis method, were shown to have nanoscopic dimensions and exhibit a high degree of crystallinity. These crystallites bound significant quantities of the water soluble, ionizable drugs tetratcycline and doxorubicin, which were released rapidly over a 1-day period. Cetyl trimethylammonium bromide (CTAB) was bound to the surface of NCC and increased the zeta potential in a concentration-dependent manner from −55 to 0 mV. NCC crystallites with CTAB-modified surfaces bound significant quantities of the hydrophobic anticancer drugs docetaxel, paclitaxel, and etoposide. These drugs were released in a controlled manner over a 2-day period. The NCC-CTAB complexes were found to bind to KU-7 cells, and evidence of cellular uptake was observed.

An ecotoxicological characterization of nanocrystalline cellulose (NCC)

The pulp and paper industry in Canada is developing technology for the production and use of nanocrystalline cellulose (NCC). A key component of the developmental work is an assessment of potential environmental risks. Towards this goal, NCC samples as well as carboxyl methyl cellulose (CMC), a surrogate of the parent cellulosic material, were subjected to an ecotoxicological evaluation. This involved toxicity tests with rainbow trout hepatocytes and nine aquatic species. The hepatocytes were most sensitive (EC20s between 10 and 200 mg/l) to NCC, although neither NCC nor CMC caused genotoxicity. In tests with the nine species, NCC affected the reproduction of the fathead minnow at (IC25) 0.29 g/l, but no other effects on endpoints such as survival and growth occurred in the other species at concentrations below 1 g/l, which was comparable to CMC. Based on this ecotoxicological characterization, NCC was found to have low toxicity potential and environmental risk.