The enormous attention and interest by both academics and industrial field for greener, biodegradable
and renewable materials implicate a persuasive trends towards the encroachment of nano-materials
science and technology in the polymer composite field. Nanocomposites creates high impacts on the
development of nano materials with advanced features to solve potential risks with their wider industrial
applications. Nano fibres are highly engineered fibres with diameters less than 100 nm that offer several
advantages over conventional fibres. One dimensional (1D) nanostructure fillers such as carbon nano
fibre and cellulose nano fibre are the most common, promising and unique for developing multifunctional
nanocomposites with better properties and extensive applications compared to micro size fibres. Nano
fibre technology brings revolution by providing products that are completely safe, truly greener, reliable
and environmentally friendly for industries, researchers and users. This review article is intended to
present valuable literature data on research and trend in the fields of carbon and cellulose nano fiber,
nanocomposites with specific focus on various applications for a sustainable and greener environment.
Olive fiber is a renewable natural fiber which has potential as an alternative biomass for extraction of microcrystalline cellulose (MCC). MCC has been widely applied in various industries owing to its small dimensional size for ease of reactive fabrication process. At present study, a serial treatments of bleaching, alkaline and acid hydrolysis was employed to extract OL-BLF, OL-PUF, and OL-MCC respectively from olive stem fiber. In morphology examination, a feature of short micro-crystallite particles was obtained for OL-MCC. The particle size was found gradually reducing from OL-PUF (305.31 μm) to OL-MCC (156.06 μm) due to the disintegration of cellulose fibrils. From physicochemical analysis, most lignin and hemicellulose components had been removed from OL-BLF to form OL-PUF with individually fibril structure. The elemental analysis revealed that highly pure cellulose component was obtained for OL-MCC. Also, the rigidity had been improved from OL-BLF to OL-PUF, while with the highest for OL-MCC with 74.2% crystallinity, endowing it as a reliable load-bearing agent. As for thermal analysis, OL-MCC had the most stable heat resistance in among the chemically-treated fibers. Therefore, olive MCC could act as a promising reinforcing agent to withstand harsh conditions for variety fields of composite applications.
Present study, deals about isolation and characterization of cellulose nanofibers (CNFs) from the Northern Bleached Softwood Kraft (NBSK) pulp, fabrication by hand lay-up technique and characterization of fabricated epoxy nanocomposites at different filler loadings (0.5%, 0.75%, 1% by wt.). The effect of CNFs loading on mechanical (tensile, impact and flexural), morphological (scanning electron microscope and transmission electron microscope) and structural (XRD and FTIR) properties of epoxy composites were investigated. FTIR analysis confirms the introduction of CNFs into the epoxy matrix while no considerable change in the crystallinity and diffraction peaks of epoxy composites were observed by the XRD patterns. Additions of CNFs considerably enhance the mechanical properties of epoxy composites but a remarkable improvement is observed for 0.75% CNFs as compared to the rest epoxy nanocomposites. In addition, the electron micrographs revealed the perfect distribution and dispersion of CNFs in the epoxy matrix for the 0.75% CNFs/epoxy nanocomposites, while the existence of voids and agglomerations were observed beyond 0.75% CNFs filler loadings. Overall results analysis clearly revealed that the 0.75% CNFs filler loading is best and effective with respect to rest to enhance the mechanical and structural properties of the epoxy composites.
The utilization of nanocellulose has increasingly gained attentions from various research fields, especially the field of polymer nanocomposites owing to the growing environmental hazardous of petroleum based fiber products. Meanwhile, the searching of alternative cellulose sources from different plants has become the interests for producing nanocellulose with varying characterizations that expectedly suit in specific field of applications. In this content the long and strong bast fibers from plant species was gradually getting its remarkable position in the field of nanocellulose extraction and nanocomposites fabrications. This review article intended to present an overview of the chemical structure of cellulose, different types of nanocellulose, bast fibers compositions, structure, polylactic acid (PLA) and the most probable processing techniques on the developments of nanocellulose from different bast fibers especially jute, kenaf, hemp, flax, ramie and roselle and its nanocomposites. This article however more focused on the fabrication of PLA based nanocomposites due to its high firmness, biodegradability and sustainability properties in developed products towards the environment. Along with this it also explored a couple of issues to improve the processing techniques of bast fibers nanocellulose and its reinforcement in the PLA biopolymer as final products.
The aim of the present research work has focused on investigating the effect of cellulose nanofibers (CNFs) and nano clays (montmorillonite (MMT) & organoclay (OMMT)) at 0.75Wt % on the performance of kenaf/epoxy composites. Mechanical (tensile and flexural) and thermal properties of composites in terms of morphology, thermal stability, weight loss, and dynamic mechanical properties were analyzed. The obtained results revealed that the integration of stiff CNFs as filler enhanced the mechanical and thermal properties, storage and loss modulus while a considerable decrease in Tan δ was realized compared to kenaf/epoxy composites. Enhancement in the properties was observed for OMMT and CNFs composites compared to MMT/kenaf/epoxy composites, which is attributed to the uniform filler distribution and interfacial adhesion between CNFs, OMMT, kenaf and epoxy matrix. The obtained results revealed that OMMT and CNFs based kenaf/epoxy composites can be an efficient alternative for construction applications.
Olive fiber is a sustainable material as well as alternative biomass for extraction of nanocrystalline cellulose (NCC), which has been widely applied in various industries. In the present study, ONC-I, ONC-II, and ONC-III were extracted from olive stem fiber at different hydrolysis reaction times of 30 min, 45 min, and 60 min, respectively. The nanoparticle size was found gradually reducing from ONC-I (11.35 nm width, 168.28 nm length) to ONC-III (6.92 nm width, 124.16 nm length) due to the disintegration of cellulose fibrils. ONC-II and ONC-III possessed highly pure cellulose compartments and enhanced crystals structure. This study also showed that rigidity increased from ONC-I to ONC-II. ONC-III showed the highest crystallinity of 83.1 %, endowing it as a potentially reliable load-bearing agent. Moreover, ONC-III exhibited highest stable heat resistance among the chemically-isolated nanocellulose. We concluded that olive NCC could be promising materials for a variety of industrial applications in various fields.
TEMPO-oxidize nanocellulose (TONC) suspension has been obtained from total chlorine free (TCF) oil palm empty-fruit-bunches (OPEFB) pulp using 4-acetamido-TEMPO (2,2,6,6-tetramethyl piperidin-1-oxyl) mediated oxidation with sodium hypochlorite and sodium bromide in water at 25 °C and pH 10. TONC suspension with varied content from 0.5 to 6% (w/w) reinforced polyvinyl alcohol (PVA) polymer based nanocomposite films were prepared by the casting method. The structural interaction between the TONC and PVA was characterized by the Fourier transform infrared (FT-IR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM). It was found that the 4% (w/w) TONC content reinforced nanocomposite exhibited the highest tensile strength and modulus with an increase of 122% and 291% respectively, compared to PVA while the elongation at break decreased about 42.7%. Thermal stability of PVA based nanocomposite films was improved after incorporation of TONC. Incorporation of TONC in PVA film increases its crystallinity due to strongly linking between the hydroxyl groups of materials however considerable decreases beyond 2 wt% loading are observed. TONC incorporation beyond 2 wt% also reduces the melting temperature peaks and enthalpy of nanocomposite films. FT-IR spectra, NMR and SEM indicate that there is interaction between the TONC and PVA.
The current study presents about the effect of cellulose nanofibers (CNFs) filler on the thermal and dynamic mechanical analysis (DMA) of epoxy composites as a function of temperature. In this study hand lay-up method was used to fabricate CNF reinforced Epoxy nanocomposites with CNF loading of 0.5%, 0.75%, and 1% into epoxy resin. The obtained thermal and DMA results illustrates that thermal stability, char content, storage modulus (E'), loss modulus (E") and glass transition temperature (Tg) increases for all CNF/epoxy nanocomposites compared to the pure epoxy. Thermal results revealed that 0.75% offers superior resistance or stability towards heat compared to its counterparts. In addition, 0.75% CNF/epoxy nanocomposites confers highest value of storage modulus as compared to 0.5% and 1% filler loading. Hence, it is concluded that 0.75% CNFs loading is the minimal to enhance both thermal and dynamic mechanical properties of the epoxy composites and can be utilized for advance material applications where thermal stability along with renewability are prime requirements.
The current study is motivated by the strict environmental regulations regarding the utilization and consumption of ecofriendly materials. In this context, the aim of this study has been to prepare and characterize different date palm tree (Phoenix dactylifera L.) fibers processed through the conventional water retting method. The chemical, elemental, crystallinity, thermal and morphological characterization of trunk (DPTRF), leaf stalk (DPLST), sheath or leaf sheath (DPLSH) and fruit bunch stalk (DPFBS) fibers was carried out. Chemical analysis revealed that the four types of date palm fibers display noteworthy differences in the content of cellulose, hemicellulose and lignin. Also, the amount of calcium is relatively high in all the date palm fibers; besides this, DPTRF exhibited 69.2% crystallinity, which is lower than that of DPLSH with 72.4% crystallinity. Moreover, DPLST and DPFBS fibers are more thermally stable (higher thermal degradation temperature) than DPTRF and DPLSH samples. Morphological analysis revealed that the fracture surface of DPFBS was relatively rougher, which would probably lead to increased bonding strength with polymers in composites. Overall, we conclude that DPFBS would be promising alternative sustainable and biomass material for the isolation of respective cellulose nanofibers and cellulose nanocrystals as potential reinforcement in polymer composites.
Herbal medicines are becoming more popular and acceptable day by day due to their effectiveness, limited side effects, and cost-effectiveness. Cholistani plants are reported as a rich source of antibacterial, antifungal, antiprotozoal, antioxidant, and anticancer agents. The current study has evaluated antiviral potential of selected Cholistani plants. The whole plants were collected, ground and used in extract formation with n-hexane, ethyl acetate and n-butanol. All the extracts were concentrated by using a rotary evaporator and concentrate was finally dissolved in an appropriate vol of the same solvent. All of the extracts were tested for their antiviral potential by using 9-11 days old chick embryonated eggs. Each extract was tested against the Avian Influenza virus H9N2 strain (AIV), New Castle Disease virus Lasoota strain (NDV), Infectious bronchitis virus (IBV) and an Infectious bursal disease virus (IBDV). Hemagglutination test (HA) and Indirect Hemagglutination (IHA) tests were performed for different viruses. The overall order of the antiviral potential of Cholistani plants against viruses was NDV>IBV>IBDV>AIV. In terms of antiviral activity from extracts, the order of activity was n-butanol>ethyl acetate>n-hexane. The medicinal plants Achyranthes aspera, Neuroda procumbens, Panicum antidotale, Ochthochloa compressa and Suaeda fruticose were very effective against all four poultry viruses through their extracts. The low IC50 values of these extracts confirm the high antiviral potential against these viruses. It is worth to mention that Achyranthes aspera was found positive against IBDV through all its extracts which overcome the problem of unavailability of any known drug against IBDV. In short, the study proved that Cholistani plants are rich source of antiviral agent and their extracts can be used as good source of antiviral drugs both in crude and in purified form.
In recent years, there has been considerable interest in the use of natural fibers as potential reinforcing fillers in polymer composites despite their hydrophilicity, which limits their widespread commercial application. The present study explored the fabrication of nanocomposites by melt mixing, using an internal mixer followed by a compression molding technique, and incorporating rice husk (RH) as a renewable natural filler, montmorillonite (MMT) nanoclay as water-resistant reinforcing nanoparticles, and polypropylene-grafted maleic anhydride (PP-g-MAH) as a compatibilizing agent. To correlate the effect of MMT delamination and MMT/RH dispersion in the composites, the mechanical and thermal properties of the composites were studied. XRD analysis revealed delamination of MMT platelets due to an increase in their interlayer spacing, and SEM micrographs indicated improved dispersion of the filler(s) from the use of compatibilizers. The mechanical properties were improved by the incorporation of MMT into the PP/RH system and the reinforcing effect was remarkable as a result of the use of compatibilizing agent. Prolonged water exposure of the prepared samples decreased their tensile and flexural properties. Interestingly, the maximum decrease was observed for PP/RH composites and the minimum was for MMT-reinforced and PP-g-MAH-compatibilized PP/RH composites. DSC results revealed an increase in crystallinity with the addition of filler(s), while the melting and crystallization temperatures remained unaltered. TGA revealed that MMT addition and its delamination in the composite systems improved the thermal stability of the developed nanocomposites. Overall, we conclude that MMT nanoclay is an effective water-resistant reinforcing nanoparticle that enhances the durability, mechanical properties, and thermal stability of composites.