Hanieh Kargarzadeh

Potential of using multiscale kenaf fibers as reinforcing filler in cassava starch-kenaf biocomposites.

Biodegradable materials made from cassava starch and kenaf fibers were prepared using a solution casting method. Kenaf fibers were treated with NaOH, bleached with sodium chlorite and acetic buffer solution, and subsequently acid hydrolyzed to obtain cellulose nanocrystals (CNCs). Biocomposites in the form of films were prepared by mixing starch and glycerol/sorbitol with various filler compositions (0-10 wt%). X-ray diffraction revealed that fiber crystallinity increased after each stage of treatment. Morphological observations and size reductions of the extracted cellulose and CNCs were studied using field emission scanning electron microscopy and transmission electron microscopy. The effects of different treatments and filler contents of the biocomposites were evaluated through mechanical tests. Results showed that the tensile strengths and moduli of the biocomposites increased after each treatment and the optimum filler content was 6%.

Cassava starch biocomposites reinforced with cellulose nanocrystals from kenaf fibers

This study highlights the potential of cellulose nanocrystals (CNCs) from kenaf fibers as reinforcing fillers in starch-based biocomposites. By hydrolyzing kenaf fibers with 65 wt.% sulfuric acid, CNCs with diameters of 12 ± 3.4 nm were obtained. Cassava starch biocomposites were prepared using a solution casting method which includes 0–10 wt.% kenaf CNCs as fillers and glycerol/sorbitol (ratio of 50:50) as plasticizer. The composites were characterized by different techniques, including tensile tests, thermal stability tests, transmission electron microscopy, field emission scanning electron microscopy (FE-SEM), water uptake tests, and observation of the physical properties of the film cast. The CNCs appeared as white, shiny dots under FE-SEM with a good dispersion of the nanofillers within the starchy matrix. The tensile strength and modulus of the biocomposite films were significantly enhanced when compared to unfilled starch films. Transparent, thin, and flexible films were obtained from both the plain matrix and 6 wt.% CNC biocomposites, confirming that CNCs may be used as fillers without affecting the composite’s transparency. Furthermore, incorporation of CNCs in the plasticized matrix led to a decrease in water sensitivity.

Hydrophobic kenaf nanocrystalline cellulose for the binding of curcumin

Nanocrystalline cellulose (NCC) extracted from lignocellulosic materials has been actively investigated as a drug delivery excipients due to its large surface area, high aspect ratio, and biodegradability. In this study, the hydrophobically modified NCC was used as a drug delivery excipient of hydrophobic drug curcumin. The modification of NCC with a cationic surfactant, cetyl trimethylammonium bromide (CTAB) was used to modulate the loading of hydrophobic drugs that would not normally bind to NCC. The FTIR, Elemental analysis, XRD, TGA, and TEM were used to confirm the modification of NCC with CTAB. The effect of concentration of CTAB on the binding efficiency of hydrophobic drug curcumin was investigated. The amounts of curcumin bound onto the CTAB-NCC nanoparticles were analyzed by UV-vis Spectrophotometric. The result showed that the modified CTAB-NCC bound a significant amount of curcumin, in a range from 80% to 96% curcumin added. Nevertheless, at higher concentration of CTAB resulted in lower binding efficiency.

Effect of Aminosilane Modification on Nanocrystalline Cellulose Properties

The application of renewable nanomaterials, like nanocrystalline cellulose (NCC), has recently been widely studied by many researchers. NCC has many benefits such as high aspect ratio, biodegradability, and high number of hydroxyl groups which offer great opportunities for modification. In this study, the NCC derived from empty fruit bunches (EFB) was modified with aminosilane, 3-(2-aminoethylamino)propyl-dimethoxymethylsilane (AEAPDMS), and the characterization was performed to investigate the potential as carbon dioxide (CO2) capture. Modification of NCC with AEAPDMS was carried out in water/ethanol solvent (80/20) (v/v) with a ratio of NCC to aminosilane of 1 : 1, 1 : 2, 1 : 3, and 1 : 4 w/w%. The effects of AEAPDMS on NCC were characterized using Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), X-ray diffraction (XRD) analysis, elemental analysis (CHNS), and transmission electron microscopy (TEM). The existence of AEAPDMS onto NCC was confirmed by ATR-FTIR spectroscopy as the new peaks of NH2 were bending and wagging, and Si-CH3 appeared. The thermal stability of NCC increased after modification due to the interaction with AEAPDMS. The elemental analysis result showed that the nitrogen content increased with an enhancement ratio of the modifiers. The XRD indicated that the crystallinity decreased while the rod-like geometry of NCC was maintained after amorphous AEAPDMS grafted on the NCC. Since AEAPDMS can be grafted on the NCC, the sample is applicable as CO2 capture.

Advances in cellulose nanomaterials

Research on nanocellulose has significantly increased over the past few decades, owing to the various attractive characteristics of this material, such as renewability, widespread availability, low density, excellent mechanical properties, economic value, biocompatibility, and biodegradability. Nanocellulose categorized into two main types, namely cellulose nanofibrils (CNFs) and cellulose nanocrystals (CNCs). In this review, we present the recent advances made in the production of CNFs and CNCs. In addition to the conventional mechanical and chemical treatments used to prepare CNFs and CNCs, respectively, other promising techniques as well as pretreatment processes have been also proposed in recent times, in an effort to design an economically efficient and eco-friendly production route for nanocellulose. Further, while the hydrophilic nature of nanocellulose limits its use in polymeric matrices and in some industrial applications, the large number of hydroxyl groups on the surface of nanocellulose provides a suitable platform for various kinds of modification treatments. The various chemical and physical surface treatment procedures reported for nanocellulose have been reviewed in this paper. Finally, in this review, we summarize the life cycle assessment studies conducted so far on nanocellulose, which quantify the environmental impact of nanocellulose products. The current paper is a comprehensive review of the recent literature on nanostructured cellulose.

Preparation and Characterizations of Cassava Starch Nanocomposite Reinforced Kenaf

The aim of this research is to prepare biodegradable plastics which are made from the natural materials. In this study, solution casting technique is used to prepare the cassava starch nanocomposite reinforced kenaf. Prior to that, kenaf fibers undergo alkali and bleaching treatments in order to prepare the cellulose. Nanocellulose which used as reinforcing nanoparticle in the composites was then prepared by acid hydrolysis of obtained cellulose with 65% sulphuric acid. The preparation of cassava starch biocomposites was done using the mixture of sorbitol/glycerol (1:1) with various cellulose loading (0%, 2%, 4%, 6%, 8% and 10%). Finer size of cellulose is examined from the transmissions electron microscopy (TEM) analysis with diameter of 12±3.04 nm and length of 70-190 nm recorded. As for field emission scanning electron microscope (FESEM) analysis, good dispersion and strong interaction between starch and cellulose had been observed for the nanocomposite films. These contribute for enhancement in the mechanical performance which demonstrated improvement of all nanocomposite films compared to the neat matrix with 6 % cellulose composition showed the highest tensile stress value of 6.3 MPa.

Properties of Aminosilane Modified Nanocrytalline Cellulose (NCC) from Oil Palm Empty Fruit Bunch (OPEFB) Fibers

Oil palm empty fruit bunch (OPEFB) is one of the lignocellulosic materials which very well known as an abundant waste at oil mills and need to be utilized. The nanocrystalline cellulose (NCC) was extracted from OPEFB fiber through several of chemical treatment and hydrolyzed with sulphuric acid (H2SO4). NCC acts as support to modify with aminosilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxy silane (AEAPDMS) which has possibility for carbon dioxide (CO2) capture. The objective of this study was to evaluate the effect of NCC properties after modified with AEAPDMS. The raw OPEFB fiber, cellulose, NCC and modified NCC were characterized by attenuated total reflectance-fourier transform infrared spectroscopy (ATR-FTIR), x-ray diffraction (XRD) but the morphology and the size of NCC was studied by transmission electron microscopy (TEM). The NCC treated with AEAPDMS was proved by FTIR with the emerging of several new peaks especially for NH2 bending and wagging around 1600 cm-1 and 798 cm-1, respectively. While, the XRD result showed the CrI of modified NCC decreased to 64 % from 76 % after the treatment due to the interaction of silanization occurred during the treatment since AEAPDMS has amorphous region. The NCC used in this study was classed as nanomaterial within nanosize and rod-like morphology observed by TEM analysis. Thus, these results give a good possibility for the AEAPDMS modified NCC to capture CO2 via covalent bonding.