Wednesday, November 30, 2022


 (Elaeis guineensis) is among important commodity in Malaysia since long ago. Currently there are more than 1.4 million hectare of oil palm grown in Malaysia as one of the largest palm oil producers in the world. However, the Oil Palm Empty Fruit Bunch (OPEFB) is considered the cheapest natural fiber with good properties and exists abundantly in Malaysia. It has great potential as an alternative main raw material to substitute woody plants as an important industry. Currently it was told that the well-known Polymeric Hydrogel has gathered a lot of interest due to its three-dimensional (3D) cross-linked network with high porosity. However, for some issues regarding its performance such as poor interfacial connectivity and mechanical strength have been raised so that nanocellulose has been introduced. In some research done by many local institutions in which the plantation of oil palm in Malaysia is discussed to show the potential of OPEFB as a nanocellulose material in hydrogel production is potentially develop. Nanocellulose can be categorized into three nano-structured celluloses in which it differs in the processing method. The most popular nanocellulose hydrogel processing methods are in few techniques. The 3D printing method is taking the lead in current hydrogel production due to its high complexity and the need for hygiene products. Some of the latest advanced applications are used to show the high approach of commercialization potential of nanocellulose hydrogel products. There are challenges and future direction of nanocellulose hydrogel. OPEFB claimed has met the requirements of the marketplace and product value chains as nanocellulose raw materials in many ways for the hydrogel applications. This article at "Anim Agriculture Technology" I am happy to discuss about the potential of the oil palm nanocellulose hydrogel for implementation in Malaysia for the future and reading purposes.

There is term called '
Regenerated Cellulose' spellout in the oil palm industry recently. It related to the 'Membrane' related in which it was the most commercial regenerated cellulose membranes (RCMs) are prepared from cellulose due to its unique hydrophilic properties, high chemical stability and ability to conserve the surrounding environment. Therefore, cellulose is an interesting raw material for an easy process development of RCM production. The cellulose membrane properties are mainly controlled by the surrounding environment, nature and coagulation mechanism. There are many efforts have been undertaken to investigate the coagulation or regeneration process to obtain a certain morphology or cellulose membrane properties. In the past few years there are new and strong organic solvent known as N-methylmorpholine-N-oxide (NMMO) has been developed. This solvent in which also can rapidly dissolve the cellulose without any complex formation. Cellulose fibers and membranes are prepared from the cellulose or NMMO or H2O solution show good mechanical and absorption properties when the cellulose solution agglomerated in water at low temperature via the phase changes method. This is the conventional method to produce RCM without a filler. The other methods are also available to incorporate the filler with the matrices via physical entanglement of polymer chains including the freeze-thaw method. Currently due to the advanced technology many research focus on the research world has mainly been on nanomaterials.

As is widely known, membranes are the most commonly used to separate different mixtures in a solution by allowing some particles to pass while the others are maintained. Two pivotal parameters for this purpose are selectivity and permeability. Thus, the efficiency of the membrane separation processes depends on these two factors. The introduction of a nanocellulose material with a combination of unique features showing chemical inertness, hydrophilic surface chemistry, high specific surface area, and high strength make it suitable as high-performance membranes. To fabricate membranes at various morphologies, several methods have been developed such as vacuum filtration, dip coating, electrospinning and solvent casting. Nanocellulose membrane is usually used as membrane materials for water purification because it can lower the organic fouling and biofouling, aside from virus removal, pollutant removal, bacteria removal, or separation of oil and water. Other than that, the polymer electrolyte with nanocellulose could not only reduce the water uptake, but also improve the thermal and mechanical stability including the reduction in volume and area swelling ratios in proton conducting membranes where it is a critical and pertinent material in both direct methanol fuel cells (DMFCs) as well as proton exchange membrane fuel cells (PEMFCs). Hence, the addition of nanocellulose could reduce the unwanted methanol crossover. In recent years, nanocellulose membranes for carbon dioxide (CO2) separation have attracted many researchers due to its promising performance, which have been reported followed by membrane distillation, organic solvent nanofiltration, and solar cells.

Hydrogel is a three-dimensional cross-linked hydrophilic polymer with the ability to absorb a large amount of water, physiological, or saline solution. It is an attractive soft material, that is suitable and applied in many areas such as pharmaceuticals, food, agriculture, food packaging, electronics, drugs delivery, and personal care products.  This is due to its hydrophilicity, permeability, good compatibility, and low coefficient of friction properties. Hydrogel can be divided into natural and synthetic hydrogels. Based on the basic crosslinking method, hydrogels can also be divided into chemical gels and physical gels. A physical gel is formed by the self-assembly of molecules through ionic and hydrogen bonding, whereas chemical gels are formed by covalent bonds. Hydrogels based on synthetic polymers such as poly (vinyl alcohol), poly(amide-amine), poly(N-isopropylacrylamide), polyacrylamide, poly (acrylic acid), and their co-polymers have been reported to be formed by cross linking agents. Unlike natural hydrogels, synthetic hydrogels like polyethylene glycol (PEG)-based hydrogels with adjustable mechanical properties and an easily controlled chemical composition can be formed through the photopolymerization process. Many natural polymer-based hydrogels fabricated using hyaluronate, alginate, starch, and cellulose have shown potential in the biomaterials area due to the hydrophilicity, biocompatibility, and biodegradation properties. Cellulose hydrogels can be prepared from a cellulose solution assisted by physical cross-linking since cellulose consists of a hydroxyl group, which can create a simple hydrogen bond network. The existence of various hydroxyl groups in the cellulose molecule enables the crystalline formation to be bonded together by the hydrogen bond. There is an intra- and inter-molecule of the hydrogen bond with van der Waals forces that exist among the non-polar group in cellulose. Hydrogels from natural polymers, especially polysaccharide, are suitable for application in biomaterials area because of its large quantity, non-toxicity, biodegradability, and biological use. Cellulose based hydrogels can be obtained from the cellulose derivative chemical cross-linked dissolved in the water by using small bifunctional molecules as a crosslink agent. Previous study has reported that a cellulose hydrogel was made by the direct dissolution process using aqueous NaOH/urea solution as a solvent and epichlorohydrin (ECH) as a cross-linker. From the study, the cellulose gelation behavior in the aqueous NaOH/urea solution and the effect of heating or cooling treatment on gelation production were investigated. Since the first report regarding hydrogel application in the biomedical area, hydrogels have been used widely in biomaterial and pharmaceutical areas for various applications including tissue engineering and drug delivery due to the good compatibility. 

Nowadays, hydrogels are designed to react with the changes in the surrounding environment such as pH, temperature, and certain mixture. Hydrogels with responsive stimulation have huge potential in pharmaceutical areas due to the unique swelling and transparency properties that enable it to change into other physical, chemical, or biological stimulations. Reported i
n recent decades, due to the capability of hydrogels to be used in a vast area and the emergence of new versatile materials such as cellulose nanomaterials have open up great new findings that show an excellent inherent chemical as well as physical properties like high specific surface area, high tensile strength, low density, high elastic modulus, reactive surfaces, and are renewable and biodegradable. These great properties have led to broad application prospects like the product known as  electroconductives, biomedicals, and optical materials including reinforcing fillers. Due to a more uniform particle size distribution and higher specific surface area, a more mechanically stable self-assembled structure of hydrogel could be formed. Other than that, with the specific cross-linking strategy, nanocellulose hydrogels demonstrate a controllable morphology, high biodegradability, and biocompatibility as well as outstanding mechanical stability. Compared to CNC, the CNF hydrogel is easily formed because it has more entanglement and flexibility. As such, many findings and published works on CNF hydrogels are available. In a previous study, a research group was the first group to show that a CNF hydrogel was possible at low concentration, followed with enzymatic and homogenization treatments. Meanwhile, a CNF hydrogel was successfully formed by adding salt or lowering the pH, and produced aligned hydrogels with oriented fibrils, which was further used as a template for anisotropic nanocomposites. An alkaline treatment was also done on a pulp before defibrillation to alter the crystal structure of CNF because it consists of both crystalline cellulose I and amorphous cellulose. The usage of NaOH concentration will affect the cellulose allomorph by the increase in cellulose II. The hydrogel with a cellulose II crystal structure showed an increase in Young’s modulus compared to the hydrogel with a cellulose I crystal structure due to the firm interdigitation of neighboring cellulose II nanofibers. However, most of the research studies have not reported on the crystallinity index or crystal structure of the CNF materials employed. Furthermore, CNF is frequently used as a reinforcing material to produce tough yet highly flexible hydrogels, especially in biomedical and tissue engineering applications. The addition of cellulose nanomaterials in regenerated cellulose membranes and hydrogels could develop a new product with exceptional properties due to its own great features. This has been proven in several previous studies, which will be further discussed in the next section. As above-mentioned, the cellulose nanomaterials were classified into several categories: CNC, CNF, and BNC. The most common nanocellulose extracted from OPEFB are CNC and CNF. Thanks...
Re arranged by,
M Anem,
(November 2022).

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