Unmodified Nanocrystalline Cellulose Research Articles

Improving properties of canola protein-based nanocomposite films by hydrophobically modified nanocrystalline cellulose

Canola meal-derived protein isolate is a sustainable source for developing food packaging materials due to its proven film-forming properties, but poor mechanical properties and high hydrophilicity limit its applications. The current study aimed to improve the properties of canola protein nanocomposite films using oleic acid (OA)-modified (hydrophobically modified) nanocrystalline cellulose (NCC) (OA-NCC). Different concentrations of unmodified NCC (U-NCC, without OA) and OA-NCC nanofillers were used to fabricate canola protein nanocomposite films via a solvent casting method, and the prepared nanocomposite films were characterized to evaluate the film properties. As a result, the tensile strength of the canola protein nanocomposite films was significantly enhanced by OA-NCC, resulting in a maximum value for OA-NCC 3 % nanocomposite films. In addition, the elongation at break percentage was increased up to 130 % by OA-NCC 7 % nanocomposite films. Moreover, the thermal stability and water barrier properties were improved because of the enhanced cohesiveness of OA-NCC and protein interactions.

Reinforcing canola protein matrix with chemically tailored nanocrystalline cellulose improves the functionality of canola protein-based packaging materials

Canola protein derived from the canola industry byproduct is a potent biopolymer source to develop sustainable food packaging materials, but it has limitations due to its poor mechanical and barrier properties. Nanomaterials such as nanocrystalline cellulose (NCC) have shown promising potential in improving material properties. The current study aimed to enhance the functionality of canola protein-based films using TEMPO ((2,2,6,6-Tetramethylpiperidin-1-yl)oxyl) modified nanocrystalline cellulose (TM-NCC). TEMPO modification was performed using TEMPO/NaClO/NaBr based oxidation. Modified and unmodified nanocrystalline cellulose (U-NCC) were used at different weight ratios to prepare the films. TEMPO-mediated oxidation converted 19.61 ± 3.53 % of primary –OH groups into –COOH groups. The addition of U-NCC and TM-NCC significantly increased the tensile strength reporting the highest value of 8.36 ± 0.85 MPa for 5% TM-NCC, which was only 3.43 ± 0.66 MPa for control films. Interestingly, both U-NCC and TM-NCC enhanced the films' water barrier and thermal properties compared to control.

Aminosilanes grafted nanocrystalline cellulose from oil palm empty fruit bunch aerogel for carbon dioxide capture

The modification of solid adsorbents with aminating agents amid severe climate change has been intensively studied. Previous organic carbon dioxide (CO 2 ) sorbent like nanoporous activated carbon develops micropores but can be easily blocked by organic amine molecules during the impregnation process. Therefore, in this study, aminosilanes with different chain lengths and nitrogen (N) content were used in nanocrystalline cellulose (NCC) modification prior to solid adsorbent aerogel fabrication to investigate their effect on pore formation, surface area, thermal stability, and capacity of CO 2 capture. The NCC derived from oil palm empty fruit bunch fiber (OPEFB) has been modified with 3-(aminopropyl) trimethoxysilane (APTMS), 3-(2-aminoethylamino) propyl-dimethoxymethylsilane (AEAPDMS), and N-(3-trimethoxysilylpropyl) diethylenetriamine (DET3) by grafting method, respectively. Based on the results, aerogel modified with the shortest chain length aminosilane, APTMS-NCC aerogel has a higher CO 2 sorption (0.20 mmol/g adsorbent) than the unmodified NCC aerogel (0.10 mmol/g adsorbent). Meanwhile, the highest surface area properties and thermal stability are demonstrated by NCC grafted by the intermediate chain length aminosilane, AEAPDMS-NCC aerogel. Thus, our work concluded that NCC's modification with low and intermediate chain length and N content aminosilanes prior to aerogel fabrication improved the pore formation, surface area, and CO 2 sorption of the aerogel. The aerogels from aminosilanes functionalized NCC could be developed as a new value-added product in the palm oil industry.

Adsorption kinetics of methyl orange from water by pH-sensitive poly(2-(dimethylamino)ethyl methacrylate)/nanocrystalline cellulose hydrogels.

A series of hydrogel nanocomposites was fabricated by in situ polymerization of 2-(dimethylamino)ethyl methacrylate (DMAEMA) in presence of different amounts of (amine- and alkyl-modified) nanocrystalline cellulose (NCC). Modification and nanocomposites properties were proved by different analysis methods such as Fourier-transform infrared spectroscopy (FT-IR), dynamic light scattering (DLS), and field emission scanning electron microscopy (FE-SEM). The new hydrogel nanocomposites were applied for removing methyl orange (MO) used as anionic dye and presented in process water at different pH values. The effects of the fabrication process such as modification and content of NCC, contact time, and pH value on swelling ratio (SR), and equilibrium adsorption kinetics were studied. Results showed that the swelling ratio of PDMAEMA-based nanocomposites varied with the different types of nanoparticles showing the significant effect of the modification process. The MO adsorption into the hydrogel nanocomposites was affected by intermolecular and electrostatic interactions between functional groups of hydrogel and dye. The adsorption capacity decreased at high pH value, and it was significantly affected type of nanoparticles introduced into the hydrogel network. The addition of unmodified NCC did not affect adsorption kinetics significantly. Finally, adsorption kinetics was investigated by pseudo-first-order, pseudo-second-order and intraparticle diffusion models where pseudo-first-order model showed the best correlation with experimental results.

Dendrimer functionalized nanocrystalline cellulose for Cu(II) removal

A series of poly(amidoamine) (PAMAM) dendrimer-functionalized nanocrystalline cellulose (NCC) composites were prepared and characterized by FTIR, XPS, XRD, TGA and TEM as well as elemental analysis. Their performance as adsorbents in Cu(II) removal from water solutions were evaluated. The influence of the initial concentration of Cu(II), pH value, contact time on the adsorption performance was studied. Compared with unmodified NCC, PAMAM functionalized NCCs show significantly higher adsorption capacity. The second generation of PAMAM functionalized NCC (NCC-2.0 PAMAM) shows a Cu(II) adsorption capacity of 92.07 mg/g at 25 °C. The adsorption isotherm of Cu(II) by NCC-2.0 PAMAM follows a Langmuir model and the adsorbent could be regenerated with 0.01 mol/L HCl.

PGlu-Modified Nanocrystalline Cellulose Improves Mechanical Properties, Biocompatibility, and Mineralization of Polyester-Based Composites.

The development of biocompatible composite materials is in high demand in many fields such as biomedicine, bioengineering, and biotechnology. In this study, two series of poly (D,L-lactide) and poly (ε-caprolactone)-based films filled with neat and modified with poly (glutamic acid) (PGlu) nanocrystalline cellulose (NCC) were prepared. An analysis of scanning electron and atomic force microscopies’ results shows that the modification of NCC with poly (glutamic acid) favored the better distribution of the nanofiller in the polymer matrix. Investigating the ability of the developed materials to attract and retain calcium ions led to the conclusion that composites containing NCC modified with PGlu induced better mineralization from model solutions than composites containing neat NCC. Moreover, compared to unmodified NCC, functionalization with PGlu improved the mechanical properties of composite films. The subcutaneous implantation of these composite materials into the backs of rats and the further histological investigation of neighboring tissues revealed the better biocompatibility of polyester materials filled with NCC–PGlu.

Surface-modified nanocrystalline cellulose from oil palm empty fruit bunch for effective binding of curcumin

Rod-shape particles have been a good drug carrier due to the long circulatory time, tumor accumulation and high cellular uptake in body. Acid-hydrolysed nanocrystalline cellulose (NCC) from empty fruit bunch exhibited a width of 13–30nm and a length of 150–360nm in rod-shape structure. NCC holds good potential as a bio-based drug carrier owing to its biodegradability and biocompatibility. Fourier-transform infrared spectroscopy results confirmed the binding of curcumin onto the NCC modified with tannic acid (TA) and decylamine (DA). TA-DA modification rendered NCC with a higher level of hydrophobicity, as evidenced by a substantial increase in contact angle from 45° to 73°. The modified NCC had the curcumin-binding efficiency in the range of 95–99%, which is at least twofold higher than the unmodified NCC at any curcumin concentration tested. This remarkable curcumin-binding effciency was comparable to that of commercialized NCC from wood-based origin. This work suggests NCC as a superior and sustainable drug carrier, while TA-DA modification is a promising approach to alter the surface property of NCC for an efficient binding of curcumin.

Adsorption and Interfacial Layer Structure of Unmodified Nanocrystalline Cellulose at Air/Water Interfaces.

Nanocrystalline cellulose (NCC) is a promising biological nanoparticle for the stabilization of fluid interfaces. However, the adsorption and interfacial layer structure of NCC are poorly understood as it is currently unknown howto form NCC interfacial layers. Herein, we present parameters for the adsorption of unmodified NCC at the air-water (A/W) interface. Initial NCC adsorption is limited by diffusion, followed by monolayer saturation and decrease in surface tension at the time scale of hours. These results confirm the current hypothesis of a Pickering stabilization. NCC interfacial performance can be modulated by salt-induced charge screening, enhancing adsorption kinetics, surface load, and interfacial viscoelasticity. Adsorbed NCC layers were visualized by atomic force microscopy at planar Langmuir films and curved air bubbles, whereat NCC coverage was higher at curved interfaces. Structural analysis by neutron reflectometry revealed that NCC forms a discontinuous monolayer with crystallites oriented in the interfacial plane at a contact angle < 90°, favoring NCC desorption upon area compression. This provides the fundamental framework on the formation and structure of NCC layers at the A/W interface, paving the way for exploiting NCC interfacial stabilization for tailored colloidal materials.

Effect of Cationic Surface Modification on the Rheological Behavior and Microstructure of Nanocrystalline Cellulose

In the present work, the microstructure and rheological behavior of nanocrystalline cellulose (NCC) and cationically modified NCC (CNCC) were comparatively studied. The resultant CNCC generally showed improved dispersion and higher thermal stability in comparison to the un-modified NCC. The rheological behavior demonstrated that the viscosity of the NCC suspension substantially decreased with the increasing shear rate (0.01–100 s−1), showing the typical characteristics of a pseudoplastic fluid. In contrast, the CNCC suspensions displayed a typical three-region behavior, regardless of changes in pH, temperature, and concentration. Moreover, the CNCC suspensions exhibited higher shear stress and viscosity at a given shear rate (0.01–100 s−1) than the NCC suspension. Meanwhile, the dynamic viscoelasticity measurements revealed that the CNCC suspensions possessed a higher elastic (G′) and loss modulus (G″) than NCC suspensions over the whole frequency range (0.1–500 rad·s−1), providing evidence that the surface cationization of NCC makes it prone to behave as a gel-like structure.

Polylactic Acid Bionanocomposites Filled with Nanocrystalline Cellulose from TEMPO-Oxidized Oil Palm Lignocellulosic Biomass

Bionanocomposites from polylactic acid (PLA) filled with unmodified nanocrystalline cellulose from TEMPO-oxidized oil palm empty fruit bunch (OPEFB-NCC) at various loading levels were fabricated using the solvent casting technique. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), attenuated total reflectance Fourier transform infrared spectroscopy (ATF-FTIR), differential scanning calorimetry (DSC), and mechanical analyses were used to characterize the bionanocomposite films. FTIR suggested that the incorporation of the OPEFB-NCC was based on physical interaction. The melting temperature did not change markedly except at higher OPEFB-NCC additions, while the crystallization temperature shifted to lower temperatures and crystallinity increased with increasing OPEFB-NCC content.The SEM of cryo-fractured films indicated a rather weak compatibility between the OPEFB-NCC and PLA, resulting in the decrease of both the modulus and the tensile strength of the bionanocomposite.

Modification of nanocrystalline cellulose for application as a reinforcing nanofiller in PMMA composites

Nanocrystalline cellulose (NCC) with particle length of 100–500 nm was prepared from microcrystalline cellulose and modified with a reversible addition–fragmentation chain transfer (RAFT) agent, i.e., 4-cyano-4-(phenylcarbonothioylthio)pentanoic acid (CPADB). From the surface of CPADB-modified NCC, methyl methacrylate (MMA) was grafted to produce poly(methyl methacrylate) (PMMA)-modified NCC. Unmodified NCC, CPADB-modified NCC, and PMMA-modified NCC were further used as reinforcing nanofillers in PMMA composite plates prepared by bulk polymerization of MMA. Regardless of NCC type, the PMMA plates were transparent to visible light at low NCC concentrations but became translucent with increasing NCC concentration. At given NCC concentration, the visible-light transparency of the PMMA/NCC composites decreased in the order PMMA-modified NCC, CPADB-modified NCC, unmodified NCC. PMMA-modified NCC and CPADB-modified NCC showed moderate potential for reinforcing the PMMA matrix, while unmodified NCC detrimentally affected the mechanical properties of the PMMA composites due to more pronounced particle aggregation.

Characterization of Surface Acetylated Nanocrystalline Cellulose by Single-Step Method

Surface acetylated nanocrystalline cellulose (NCC) was prepared from cotton fiber by a single-step method under mild conditions using anhydrous phosphoric acid as the solvent. The absorbance peak of O-H was reduced, and the absorbance peaks of C=O and CH3 appeared in the Fourier transform infrared (FTIR) spectrum of the acetylated NCC with respect to that of the unmodified NCC. The roughly estimated degree of substitution was a little greater than 1.5 by FTIR analyses, implying that most of the free hydroxyl groups on the NCC surface were acetylated at 40 °C for 3 h. The carbons of the acetyl groups were clearly identified in the 13C cross polarization-magic angle spinning (CP-MAS) nuclear magnetic resonance (NMR) spectrum. The zeta potential was reduced from -32.12 mV to -20.57 mV after acetylation. Transmission electron microscope (TEM) and field-emission scanning electron microscope (FESEM) images showed that they were thread-like nano-crystals with a diameter less than 5 nm. Crystal structure analysis using X-ray diffraction (XRD) demonstrated that the acetylated NCC had the typical CelluloseⅡstructure. The PLA film reinforced with 3 wt% acetylated NCC content exhibited the highest tensile strength, which was increased by 117% compared to the control. SEM observation demonstrated good interfacial interaction between the acetylated NCC and the matrix.

Hydrophilic modification of polyester fabric by applying nanocrystalline cellulose containing surface finish

In this study, polyethylene terephthalate (PET) fabric was modified by applying a hydrophilic surface finishing agent that contains nanocrystalline cellulose (NCC). To impart superior hydrophilicity, NCC was further cationically modified through quaternization by grafting glycidyl tri-methyl ammonium chloride (GTMAC). A textile binder, PrintRite595®, was added to the finishing system. The surface finish was applied on the fabric using a rolling–drying–curing process. The modified fabric was characterized in terms of coating durability, moisture regain, and wettability. The durability of the surface finish was tested by six repeated washing steps. The surface properties of the fabric changed from hydrophobic to hydrophilic after heat treatment with the NCC-containing surface finishing agent. The results from the washing fastness, SEM, FTIR, and EDX analyses confirmed that the cationic NCC-containing textile surface finish showed superior adhesion onto the cationic dyeable (anionic) PET surface over the un-modified NCC. Furthermore, the cationic textile surface finish was capable of withstanding multiple washing cycles.

Synthesis and characterization of cationically modified nanocrystalline cellulose

In this study, nanocrystalline cellulose (NCC) resulting from sulfuric acid hydrolysis of wood cellulose fiber, was rendered cationic by grafting with glycidyltrimethylammonium chloride (GTMAC). An optimization of the reaction parameters, such as water content, reactant mole ratio, and reaction media was performed. The presence of cationic GTMAC on the surface of NCC was confirmed by Fourier Transform Infrared Spectroscopy (FTIR). The cationically modified NCC was characterized by surface charge density, degree of substitution, ζ potential, and particle size. It was found that the cationic surface charge density of NCC can be increased by controlling the water content of the reaction system. Surface cationization of NCC led to an increase in the surface charge density over the un-modified NCC. The cationically modified NCC was well dispersed and stable in aqueous media due to enhanced cationic surface charge density. Transmission electron microscopy (TEM) images showed the improvement in state of dispersion of cationically modified NCC over the un-modified NCC. The optimum water content was found to be 36wt% for aqueous based media and 0.5 water to DMSO volume ratio for aqueous–organic solvent reaction media. The increased surface charge density of NCC also delayed the onset of gelation in aqueous system.