Recently, researchers and scientists are trying to overcome the environmental burden by using biocomposites in engineering applications as far as possible. The main source of biocomposites is ...cellulosic fibres which is a class of natural fibres. Instead of many advantages of cellulosic fibres, they and their polymer composites suffer from some limitations as well. The environmental conditions are one of the most important issues to degradation behavior of the cellulosic fibres polymer composites (CFPCs). Among the environmental conditions, water absorption is an important ground to degradation in the mechanical performance of the CFPCs, which resists them to be used in outdoor applications. Several studies have been presented on water absorption characteristics of cellulosic fibres and its polymer-based biocomposites. Further, the consequence of water uptake on the mechanical performance of biocomposites was also reported in many studies. In most of the cases, a negative effect of water absorption was observed, whereas in a few cases a positive effect was also seen. In the present study, mechanics and kinetics of water absorption for CFPCs are discussed. Further, a detailed literature review on water absorption of cellulosic fibres and their different types of polymer-based biocomposites has also been carried out. Furthermore, studies reported on the effect of water absorption on the mechanical properties were also systematically presented. Moreover, all the possible remedies to lower the water absorption capacity were also discussed in the present review paper.
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Silica⿿cellulose aerogels were successfully developed from recycled cellulose fibres and methoxytrimethylsilane (MTMS) silica precursor for the first time.The silica⿿cellulose ...aerogels showed the super-hydrophobicity with an average water contact angle of 151°.The silica⿿cellulose aerogels developed in this work showed a promising potential for thermal and acoustic insulation applications.This work provides a facile approach to fabricate cost-effective silica⿿cellulose aerogels with industrial dimensions.
Silica⿿cellulose aerogels were successfully developed from recycled cellulose fibres and methoxytrimethylsilane (MTMS) silica precursor for the first time. The developed silica⿿cellulose aerogels showed the super-hydrophobicity with an average water contact angle of 151°. Their thermal conductivity was approximately 0.04W/mK. Moreover, the thermal degradation temperature for the cellulose component of the silica⿿cellulose aerogels showed a 25°C improvement over those for cellulose aerogels. The sound absorption coefficients of the silica⿿cellulose aerogels with a 10mm thickness were 0.39⿿0.50, better than those of cellulose aerogels (0.30⿿0.40) and commercial polystyrene foams. When the cellulose fibre concentration increases from 1.0 to 4.0wt.%, the compressive Young⿿s modulus of the silica⿿cellulose aerogels can be enhanced 160%, up to 139KPa. This work provides a facile approach to fabricate cost-effective and promising silica⿿cellulose aerogels with industrial dimensions for thermal and acoustic insulation applications.
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•Natural cellulose fibres as photoanode and electrolyte for dye-sensitized solar cells.•TiO2-laden paper foils as photoanodes obtained by papermaking.•Nanoscale microfibrillated ...cellulose as polymer electrolyte.•Efficiencies as high as 3.55% under 1 sun irradiation.•Stability equal to 96% after 1000h of accelerated aging test.
Natural cellulose fibres are proposed as promising components for bioderived photoanodes and polymer electrolytes in dye-sensitized solar cells (DSSCs). In particular, TiO2-laden paper foils, prepared by simple papermaking, can be applied to several substrates (conductive glass or plastics) instead of the high-temperature sintered traditional commercial pastes. In addition, nanoscale microfibrillated cellulose is used as reinforcing filler in acrylate/methacrylate-based thermo-set polymer electrolyte membranes prepared by means of fast, low-cost and green UV-induced free-radical photopolymerization. The laboratory-scale quasi-solid state paper-DSSCs assembled with cellulose-based electrodes and electrolytes guarantee sunlight conversion efficiencies as high as 3.55 and 5.20% at simulated light intensities of 1 and 0.2 sun, respectively, along with an excellent efficiency retention of 96% after 1000h of accelerated aging test. The simple, low cost and green approach here specifically developed opens up intriguing prospects in the design of bio-inspired energy conversion devices showing high performance, outstanding durability and truly sustainable characteristics.
Interfacial interactions are key to the development of high-performance coatings such as conductive polymer layers on fibrous materials. In this work, we present an approach of strengthening the ...interaction by forming ionic bonds between cellulose fibres and the conductive polymer layer by introducing a sulfonate group on cellulose fibres. The ionic bonds are formed between anchored sulfonate group and the positively charged precursor 3,4-ethylenedioxythiophene (EDOT), followed by the deposition and polymerisation of poly(3,4-ethylenedioxythiophene):sulfate (PEDOT:SO4) on the fibrous substrate surface. The conductance of the PEDOT:SO4 coated substrate with anchored sulfonate groups coated may be 1.7 times higher compared to the conductance of the unmodified cellulose substrate depending on experimental conditions. EDX measurements confirm the presence of sulfur and a shift of zeta potential at lower pH supports the evidence of the anionic anchored groups on the fibre surface. Our study therefore provides a new way to enhance the affinity of fibrous cellulose materials towards polymer conductive coatings.
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•Successful grafting of sodium 4-((4,6-dichloro-1,3,5-triazin-2-yl)amino)benzenesulfonate on cellulosic fibres.•Formation of ionic bonds between anchored sulphonate group and positively charged precursor 3,4-ethylenedioxythiophene.•Higher yield of deposition polymerisation of poly(3,4-ethylenedioxythiophene) on modified fibre substrate.
The dissolution of cellulose in different ionic liquids will be described as a very recent subject for a direct dissolving process, which was used to prepare regenerated cellulose fibres. The ...preparation of the dopes was arranged starting from slurry of cellulose in the aqueous ionic liquid by removing the water at elevated temperature, vacuum and high shearing rates. As ionic liquids, the 1-N-Butyl-3-methylimidazolium chloride, the 1-Ethyl-3-methylimidazolium chloride, the 1-N-Butyl-2,3-dimethylimidazolium chloride, the 1-N-Butyl-3-methylimidazolium acetate and the 1-Ethyl-3-methylimidazolium acetate were investigated. The cellulose solutions in ionic liquids were characterised by means of light microscopy, cone-plate rheometry and particle analysis. In addition these results were compared with cellulose solutions in N-methyl-morpholine-N-oxide monohydrate. Finally the cellulose dopes were shaped by a dry-wet spinning process to manufacture cellulose fibres. The properties of the resulted fibre had been determined and will be discussed.
Various polylactic acid (PLA) blends were reinforced with untreated or silane-treated micro-sized cellulose fiber (MCF), successfully prepared as 3D printing filaments and then printed using a fused ...filament fabrication (FFF) 3D printer. In this study, we focused on developing 3D-printed MCF/PLA composites through silane treatment of MCF and investigating the effect of silane treatment on the various properties of FFF 3D-printed composites. Fourier transform infrared spectra confirmed the increase in hydrophobic properties of silane-treated MCF by showing the new absorption peaks at 1,100 cm -1 , 1,030 cm -1 , and 815 cm -1 representing C-NH 2 , Si-O-Si, and Si-CH 2 bonds, respectively. In scanning electron microscope images of silane-treated MCF filled PLA composites, the improved interfacial adhesion between MCF and PLA matrix was observed. The mechanical properties of the 3D-printed MCF/PLA composites with silane-treated MCF were improved compared to those of the 3D-printed MCF/PLA composites with untreated MCF. In particular, the highest tensile and flexural modulus values were observed for S-MCF10 (5,784.77 MPa) and S-MCF5 (2,441.67 MPa), respectively. The thermal stability of silane-treated MCF was enhanced by delaying the initial thermal decomposition temperature compared to untreated MCF. The thermal decomposition temperature difference at T 95 was around 26℃. This study suggests that the effect of silane treatment on the 3D-printed MCF/PLA composites is effective and promising.
Cellulose fibre (CF) has been widely employed as an adsorbent because of its effective capacity for adsorbing toxic components of cigarette smoke. There is a lack of studies of CF adsorbing ...pharmaceuticals from water. Herein, we evaluated the adsorption of potassium diclofenac (PD) from an aqueous medium by CF. In addition, we developed and prepared CF covered with polypyrrole (PPy) to improve the adsorptive capacity for removal of PD. From the infrared characterization, the main bands related to the functional groups of each component, PPy and CF, were identified; in thermogravimetry it was observed that both the CF and composite support relatively high temperatures and in the scanning electron microscopy it was possible to observe that the composite has a fibrous structure related to CF in which PPy particles are aggregated. In adsorption studies of PD in an aqueous medium, the pH, the contact time between the material and analyte and equilibrium concentration were evaluated. The first study carried out was the influence of pH on the adsorbed amount of PD, the optimum pH chosen for the experiments being 2.0 and 6.0 for CF and PPy/CF, respectively. In the kinetic study, adsorption occurred rapidly and equilibrium times were achieved within 30min (CF) and 15min (PPy/CF). The kinetic data were analysed using four models: pseudo-first-order, pseudo-second-order, Elovich and intraparticle diffusion and the adsorption kinetics were best described by the pseudo-second-order model with R2=0.999 for both materials, indicating that a chemical adsorption occurred. The Langmuir, Freundlich, Sips, single-site Langmuir–Freundlich and dual-site Langmuir–Freundlich models were used to analyse the adsorption equilibrium data obtained by the variation of the PD concentration in the aqueous solution and the dual-site Langmuir–Freundlich model presented the best fits, CF: R2=0.982 and PPy/CF: R2=0.997, indicating that there are two types of sites available for adsorption, homogeneous and heterogeneous, in the assessed materials. In addition, the composite had the best maximum adsorptive capacity, Q=210.07mgg−1, while the CF presented Q=50.33mgg−1.
Herein, we presented the preparation of cellulose fibre (CF) decorated with polypyrrole (PPy) as an efficient adsorbent for removal of potassium diclofenac (PD) from aqueous medium, which can be used in separation process as solid phase extraction and chromatographic and electrophoretic techniques. The kinetics and isotherms studies showed a great potential of this material for this purpose. The PPy/CF were prepared via in situ polymerization and characterized by FTIR, TG and SEM.
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•New composite adsorbent (PPy/CF) was easily synthesized and well characterized.•PPy/CF was efficient for removal of PD from aqueous medium.•Adsorption studies allowed understanding the adsorption mechanism of PD onto PPy/CF.•PPy/CF showed excellent adsorption capacity compared to pure CF.•PPy/CF presented good stability over a wide pH range (pH2–10).
We are directly exposed to microplastic contamination via indoor air that we breathe daily, for which the characterisation of microplastics is still a challenge. Herein, two typical air filter ...samples were collected, one from an air-conditioner and another from a personal computer, both of which have been working for around half a year to collect and accumulate microplastics in the indoor air, like microplastic banks. After the sample preparation to remove the mineral dusts, Raman imaging was employed to directly and simultaneously identify and visualise microplastics of polyethylene terephthalate (PET) fibres, distinguish them from other fibres such as cellulose and cross-check them with a scanning electron microscope (SEM). To count the microplastics and to avoid the quantification bias, several areas were randomly scanned and imaged to statistically estimate the percentage of microplastic fibres in the analysed samples. The microplastics amount, which has been estimated at 73-88,000 fibers per filter per half a year, varies and depends on the indoor environment so that the air filter can work as a good indicator to monitor the quality of the indoor air from the microplastic perspective. Overall, human are directly exposed to this emerging contamination every day, raising environmental concerns. Raman imaging characterisation and its corresponding statistical information can help pursue further research on microplastics.
This review presents the research conducted to date in the field of cement-based composites reinforced with waste paper-based cellulose fibres, focusing on their composition, mechanical properties, ...and durability characteristics. The literature demonstrates that the properties of raw material (depending on their own chemical composition) significantly influence the formation of the cement composite binders. When considering fresh properties, the presence of silica and magnesium compounds generally lead to favourable effects on the setting of the cement composite when combined with waste paper cellulose fibre. Reduction in density values, i.e., approximately 25%, was observed with the inclusion of waste paper fibres from 20 to 80% in cement composites. The homogeneous dispersion of fibres in the matrix is one of the crucial factors to achieve in order to develop composites with well-balanced mechanical properties incorporating waste paper cellulose fibres. Hence, dispersion of fibres can be improved by increasing water quantity corresponding to the optimal value, which was a water/cement ratio of 0.64 leading to optimum strength properties of the composite. Even though the effect of fibre dispersion in the matrix improves with the addition of water, higher porosity and voids govern the strength properties beyond an optimum water-to-cement ratio. Higher porosity leads to an increase in the water absorption and a lowering of the thermal conductivity properties with the addition of paper fibre in cement binders. Paper fibre absorbs a high amount of water leading to higher water absorption. This phenomenon is related to the hydrophilic nature of cellulosic fibres absorbing some volume of water due to their microporous structure.
