Shell Fibers Research Articles

Physicochemical characteristics of organosolv lignins from different lignocellulosic agricultural wastes

Lignin is a promising alternative to petrochemical precursors for conversion to industrial-needed products. Organosolv lignins were extracted from different agricultural wastes including sugarcane bagasse (BG) and trash (ST), corncob (CC), eucalyptus wood (EW), pararubber woodchip (PRW), and palm wastes (palm kernel cake (PKC), palm fiber (PF), and palm kernel shell (PKS), representing different groups of lignin origins. Physicochemical characteristics of lignins were analyzed by several principal techniques. Most recovered lignin showed high purity of >90 % with trace sugar contamination, while lower purities were found for lignin from palm wastes. Hardwood lignins (EW and PRW) mainly contained guaiacyl (G) and syringyl (S) units with a minor fraction of p-hydroxyphenyl units (H) with high molecular weight, glass transition temperature, phenolic hydroxy group and low aliphatic hydroxy group. Grass-type lignins (BG, ST, CC) and palm lignins (PKC, PF, and PKS) contained three monolignols of H, G, and S units with lower molecular weights and C5-substituted hydroxy of S unit. Among the grass-type lignins, PKC lignin contained the highest nitrogen and lipophilic components with the lowest molecular weight, thermal stability, and glass transition temperature. This provides insights into properties of organosolv lignin as basis for their further applications in chemical, polymer and material industries.

Physico-chemical/mechanical properties of treated groundnut shell fibre; Response surface methodology and artificial neural network performance evaluation and optimisation

The difficulties associated with forecasting mechanical behaviours of fibres based on the theoretical method is a big threat to precise design when dealing with complex variables; hence, the need to evaluate the fibres' properties using artificial intelligence techniques to minimise error. This study predicted the effect of acetylation process parameters (treatment time and concentration) on the mechanical properties (elongation at break and tensile strength) of groundnut shell fibre (GSF) using Response surface methodology (RSM) and Artificial neural network (ANN). The GSF was processed, dried and treated with NaOH varying the time and concentration of the treatment and then acetylated. The characterisation results from the physicochemical analysis, SEM and FTIR indicated that acetylation treatment removed excess lignin, hemicellulose and cellulose from GSF and improve its bonding characteristics. Assessment of the models through the coefficient of determination (R2) and mean square error (MSE) indicates that ANN for elongation at break (R2 =0.9999, MSE=2.769E-13) and tensile strength (R2 =0.99997, MSE=3.5146E-18) is superior to the RSM model for elongation at break (R2 =0.9264, MSE 1.59) and for tensile strength (R2 =0.9326, MSE=7.71) in predicting mechanical properties of GSF. Numerical optimisation revealed that optimal values of 3 h and treatment concentration of 3% gave a maximum percentage elongation at break of 10.583% and 135.045 MPa for tensile strength. This result shows that acetylation treatment enhanced the physicochemical/mechanical properties of GSF thereby making it suitable for composite processing.

Characterization of Biochar Empty Fruit Bunches OPEFB at Various Temperatures and Burning Time

Oil palm waste (OPW), comprising mainly of empty fruit bunch, mesocarp fiber, frond, trunk, and palm kernel shell generated from the palm oil industry, was collected, characterized, and then pyrolyzed to evaluate their potential to be converted into biochar. Oil Palm Empty Fruit Bunches (OPEFB) are a source of organic material with abundant nutrients and are highly potentially useful as biochar. This article provides experimental data for the production of biochar at a temperature range of 100 to 300 °C at time of 4 to 8 hours. The chemical components examined are pH, CEC, C-Organic, N-total, C/N, K dd, P, Ca, Mg, and Na, using Fourier Transform Infrared Spectroscopy (FTIR). The results showed that organic C, nitrogen, and pH were highest at 200–300 °C and had a burning time of 8 hours. Furthermore, the highest concentrations of P, Ca, and Mg were recorded at 200–300°C after 5 hours, Kdd at 100–200 °C after 5 hours, and Na and CEC at 200–300 °C after 4 hours. The transmittance intensity produced by the spectrum of hydroxyl (O-H) vibrations, carbonyl stretching (C=O), alkanes (-CH), and aromatics (C=C) decreased with increasing time, while stretching alcohol (C-O) vibrations increased with time. Our results demonstrate that OPEB is a biowaste that shows exceptional promise to be transformed into high-grade biochar rather than simply disposed of by landfilling or burning.

Influencing Behavior Study of Natural Almond Shell Filler on the Tensile, Thermal, and Free Vibrational Properties of Flax Fiber Intertwined Vinyl Ester Composites

ABSTRACT The structural porosity weakness of a natural flax fiber-layered polymer laminate was reduced by the spatial rearrangement of natural almond shell filler occupying preferentially porous sites between the stacking layers, improving the properties of the polymer laminate. The present work investigates the mechanical, thermal, and free vibrational behavior of composites, including surface modification and the effect of almond shell filler loading in the flax fiber intertwined composites. Alkaline treatment of natural flax fiber and almond shell filler effectively reduced the hydrophilic contents of hemicellulose, lignin, and wax without altering the cellulose nature, as confirmed by FTIR analysis. Tensile strength was 35% higher for the alkaline-treated 10% almond shell-filled composite than the untreated filler composite. However, the tensile strength decreased beyond 10% of filler loading because of the poor dispersion of fillers in the matrix. As evident in the 10% filled almond shell composite, due to stronger interaction, polymer-mixed almond fillers act as a thermal insulating layer between the flax stacks, increasing thermal stability. Alkali treatment with an almond shell of 10 wt% filled flax fiber composite exhibited a higher natural frequency (185 Hz) and damping value (0.042) due to total internal dissipation of dynamic forces.

Elaborate design of shell component for manipulating the sustained release behavior from core–shell nanofibres

BackgroundThe diversified combination of nanostructure and material has received considerable attention from researchers to exploit advanced functional materials. In drug delivery systems, the hydrophilicity and sustained–release drug properties are in opposition. Thus, difficulties remain in the simultaneous improve sustained–release drug properties and increase the hydrophilicity of materials.MethodsIn this work, we proposed a modified triaxial electrospinning strategy to fabricate functional core–shell fibres, which could elaborate design of shell component for manipulating the sustained-release drug. Cellulose acetate (CA) was designed as the main polymeric matrix, whereas polyethylene glycol (PEG) was added as a hydrophilic material in the middle layer. Cur, as a model drug, was stored in the inner layer.ResultsScanning electron microscopy (SEM) results and transmission electron microscopy (TEM) demonstrated that the cylindrical F2–F4 fibres had a clear core–shell structure. The model drug Cur in fibres was verified in an amorphous form during the X-ray diffraction (XRD) patterns, and Fourier transformed infrared spectroscopy (FTIR) results indicated good compatibility with the CA matrix. The water contact angle test showed that functional F2–F4 fibres had a high hydrophilic property in 120 s and the control sample F1 needed over 0.5 h to obtain hydrophilic property. In the initial stage of moisture intrusion into fibres, the quickly dissolved PEG component guided the water molecules and rapidly eroded the internal structure of functional fibres. The good hydrophilicity of F2–F4 fibres brought relatively excellent swelling rate around 4600%. Blank outer layer of functional F2 fibres with 1% PEG created an exciting opportunity for providing a 96 h sustained-release drug profile, while F3 and F4 fibres with over 3% PEG provided a 12 h modified drug release profile to eliminate tailing–off effect.ConclusionHere, the functional F2–F4 fibres had been successfully produced by using the advanced modified triaxial electrospinning nanotechnology with different polymer matrices. The simple strategy in this work has remarkable potential to manipulate hydrophilicity and sustained release of drug carriers, meantime it can also enrich the preparation approaches of functional nanomaterials.Graphical

Hydrodynamic Spinning of Protein Fractal Aggregates into Core–Shell Fibers

Hydrodynamic Spinning of Protein Fractal Aggregates into Core–Shell Fibers

Eco-friendly chitosan@silver/plant fiber membranes for masks with thermal comfortability and self-sterilization.

The surgical masks have been essential consumables for public in the COVID-19 pandemic. However, long-time wearing masks will make wearers feel uncomfortable and massive discarded non-biodegradable masks lead to a heavy burden on our environment. In this paper, we adopt degradable chitosan@silver (CS@Ag) core–shell fibers and plant fibers to prepare an eco-friendly mask with excellent thermal comfort, self-sterilization, and antiviral effects. The thermal network of CS@Ag core–shell fibers highly improves the in-plane thermal conductivity of masks, which is 4.45 times higher than that of commercial masks. Because of the electrical conductivity of Ag, the fabricated mask can be electrically heated to warm the wearer in a cold environment and disinfect COVID-19 facilely at room temperature. Meanwhile, the in-situ reduced silver nanoparticles (AgNPs) endow the mask with superior antibacterial properties. Therefore, this mask shows a great potential to address the urgent need for a thermally comfortable, antibacterial, antiviral, and eco-friendly mask.Graphical abstract Supplementary InformationThe online version contains supplementary material available at 10.1007/s10570-022-04582-x.

Alginate functionalized biomimetic 3D scaffold improves cell culture and cryopreservation for cellular therapy

The clinical translation of cellular therapy is hampered by the scarcity of reliable and consistent cell sources. In this study, we developed an exquisite scaffold featuring the hierarchical structure and biofunctions of silkworm cocoons (CryoSiCo), for boosting cell manufacture and cryopreservation. CryoSiCo was constructed by a creative bottom-up fabrication technique integrating electrospinning, in situ surface functionalization and freeze-shaping, generating a 3D cocoon-mimicking fibrous scaffold composed of graphene oxide-incorporated polylactic acid/gelatin inner fiber core and alginate outer fiber shell. CryoSiCo provided rapid and uniform rewarming for cryopreserved cells, and maximally maintained cell viability and proliferation capability, allowing for effective cryopreservation. Importantly, CryoSiCo could cryopreserve stem cell-scaffold constructs with high cell survival and functions, which can be directly implanted to restore tissue defects. Thus, CryoSiCo represents an appealing biomimetic strategy for storing precious cells and tissue engineered constructs, showing a broad application for fundamental research and applied medicine.

A micromechanical and numerical model for effective thermal conductivity of areca fiber and coconut shell particulate-reinforced hybrid composites

The present investigation reports on the thermal conductivity of areca fiber and coconut shell particulate (CSP)-reinforced polymer composites. The fiber and particulate reinforcement percentages were 10–40wt.% with various weight ratios as 1:1, 1:3, and 3:1. The main focus has been given to the development of a micromechanical model to calculate the effective thermal conductivity of areca fiber and CSP-reinforced hybrid composites. In the numerical study, steady-state one-dimensional heat conduction analysis is performed with a periodic arrangement of cylinders and spherical reinforcement using ANSYS software. Unitherm [Formula: see text]Model 2022 equipment was used to measure the experimental thermal conductivity values of the hybrid composite materials and validated with the micromechanical and numerical values. The experimental results attained for thermal conductivity are supported by the proposed micromechanical model. The measured values of the composites were found to be in very close agreement with the micromechanical model and the numerical analysis. It is concluded from this study that the addition of areca fiber and CSP improves the thermal insulation capability of neat epoxy.

Sequential Infiltration Synthesis for High-Precision Fabrication of Applied Ceramic Fibers with Designed Nanostructures─Nanowires, Nanobelts, and Core–Shell Fibers

Sequential Infiltration Synthesis for High-Precision Fabrication of Applied Ceramic Fibers with Designed Nanostructures─Nanowires, Nanobelts, and Core–Shell Fibers

Significant Electromechanical Characteristic Enhancement of Coaxial Electrospinning Core-Shell Fibers.

Electrospinning is a low-cost and straightforward method for producing various types of polymers in micro/nanofiber form. Among the various types of polymers, electrospun piezoelectric polymers have many potential applications. In this study, a new type of functional microfiber composed of poly(γ-benzyl-α,L-glutamate) (PBLG) and poly(vinylidene fluoride) (PVDF) with significantly enhanced electromechanical properties has been reported. Recently reported electrospun PBLG fibers exhibit polarity along the axial direction, while electrospun PVDF fibers have the highest net dipole moment in the transverse direction. Hence, a combination of PBLG and PVDF as a core–shell structure has been investigated in the present work. On polarization under a high voltage, enhancement in the net dipole moment in each material and the intramolecular conformation was observed. The piezoelectric coefficient of the electrospun PBLG/PVDF core–shell fibers was measured to be up to 68 pC N−1 (d33), and the voltage generation under longitudinal extension was 400 mVpp (peak-to-peak) at a frequency of 60 Hz, which is better than that of the electrospun homopolymer fibers. Such new types of functional materials can be used in various applications, such as sensors, actuators, smart materials, implantable biosensors, biomedical engineering devices, and energy harvesting devices.

Evaluation of Feasibility for Novel Modular Block Construction

The construction industry needs fast construction technology and modular construction in the future. Living in poverty is a problem for 21.9 percent of the population in India, with 98 percent of the shortage occurring in low-income and Economically Weaker Sections (EWS). In addition, 40 percent of agricultural products go to waste due to inadequate handling and storage infrastructure. We all know that plastic harms the environment. Further CO2 production during cement manufacturing is a major environmental issue. A ton of cement emits 1.25 tonnes of CO2. After considering all these issues, we propose to use gypsum, steel curls, and coconut shell fiber to produce ideal-sized modular units and test their strength and economy. The sample casting had been carried out, and the testing of the basic parameters was accomplished in the study.

Computational model and simulation of DCMD desalination systems with heat recovery

Desalination technologies can help mitigating the water scarcity problem facing humankind. Membrane distillation (MD) is a desalination technology attractive for its adequacy to use low-grade waste heat or renewable energy sources. This work addresses the modelling of a Direct Contact Membrane Distillation (DCMD) plant with heat recovery. The desalination unit comprises several DCMD modules, each of a shell and hollow fibre tube bundle type. A multiscale approach is needed to address the problem. It includes modelling of the vapour flux through the micro/nano porous membrane, models for the mass and energy conservation at the scale of a single DCMD module, and thermodynamic modelling at the scale of the desalination plant. Analytical solutions of the mass and heat transfer across the membranes are combined with finite volume discretised equations describing heat and mass conservation for the feed and permeate streams. An iterative scheme is devised to solve the model equations in order to determine the flow and temperature variables in the DCMD module. The computational model predictions show good agreement with experimental data available in the literature. Finally, the methodology presented herein is used to simulate the performance of a DCMD desalination plant with heat recovery.

Development of gelatin film deposited with carvacrol‐loaded fibers and its application to sea bass fillet preservation

Developing new methods to encapsulate fragile active compounds into packaging films is important for extending the shelf life of foods. In this study, the gelatin/fiber bilayer packaging film was fabricated by depositing carvacrol-loaded core–shell zein/polyvinyl pyrrolidone fibers on gelatin film. The tensile strength, elongation, oxygen transmission rate, and water vapor permeability of the gelatin/fiber film were 5.95 MPa, 56.63%, 63.27 ml/m2 d, 0.1 MPa, and 7.416 g·mm/m2 h kPa, respectively. The gelatin/fiber film was applied to sea bass fillet preservation. At day 8, the total viable count and thiobarbituric acid of the sea bass fillets treated with gelatin/fiber film were 8.12 log CFU/g and 0.73 mg MDA/kg, which were lower than that of the control group. Moreover, the gelatin/fiber film treatment showed the effect of delaying fish color change and pH increase, and prolonged the shelf life of sea bass fillets by 2–4 days. Novelty impact statement Gelatin film deposited with carvacrol-loaded core–shell fibers was prepared. Shelf life of Japanese sea bass fillets was extended by the gelatin/fiber film. The active bilayer film showed high antimicrobial and antioxidant activities.

Extraction and Characterization of Bamboo Shoot Shell Fibers by Sodium Percarbonate Assisted Degumming

ABSTRACT The bamboo shoot shell fibers were extracted by using environmental protection oxidant sodium percarbonate combined with alkali oxygen bath method. To explore the influence of various factors on its degumming, the efficiency of degumming through single-factor and orthogonal experiments was assessed. The results showed that the used method had a good effect on the degumming of bamboo shoot shell fiber, and most of the non-cellulose components such as hemicellulose, lignin, and pectin had been removed. After the treatment, the cellulose content and crystallinity were 73.19% and 61.40%, respectively. Taking the degumming rate as the index, the factors such as dosage of sodium percarbonate and hydrogen peroxide, soaking temperature, and time in alkali boiling treatment were optimized. The results showed that the degumming rate was 69.17% when the scouring temperature was 90°C, the alkali boiling time was 120 min, the dosage of sodium percarbonate was 24 g/L, and the dosage of hydrogen peroxide was 40 mL/L. The structure and properties of bamboo shoot shell fiber were analyzed by scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analyzer (TGA). The prepared bamboo shoot shell fibers would be considered as a promising and sustainable raw material for the textile industry and other prospects in the future.

Cultivation of Schizophyllum commune Fries (CP-433) on corn stubble (Zea mays L.) and peanut shell (Arachis hypogaea L.) in Mexico

Schizophyllum commune Fr. is a mushroom with a worldwide distribution; it is a food source in several countries and produces medicinal substances. It has been cultivated on sawdust and agricultural byproducts. In the present study, corn stubble (Zea mays L., stem with dry leaves) and peanut shell (Arachis hypogaea L., dry pericarp) were used as substrates for the cultivation of a strain (CP-433) of S. commune. The parameters evaluated were days in the formation of fruiting primordia, the number of harvests, days of the total cycle, biological efficiency (BE), production rate (PR) and yield (Y). Primordia formed between 12 and 13 days and later at 16 days. Two harvests with a total cycle of 22 days were made. The BE was 16.8±7.0% and 17.9±3.2%, the PR was 0.39±0% and 0.29±0.05%, and the Y was 1.68±0.7% and 1.79±0.3% for corn stubble and peanut shell, respectively, without significant differences between the two. The cultivation cycle in this study was shorter than the cultivation of S. commune on cocoa shell and coconut fiber (47 days), on sunflower seed shell (30-31 days), on oil palm fruit waste (29 days), and on palo mulato, cocoa shell and banana leaf (26-27 days). The values reached in BE are similar to other studies in which S. commune was cultivated on corn stalks and cobs (5.5%) and on palo mulato (6.4%). Corn stubble and peanut shells are promising substrates for the cultivation of S. commune on a small or large scale, mainly in the regions where they are discarded.

Effect of Graphene Oxide and Nanosilica Modifications on Electrospun Core-Shell PVA-PEG-SiO2@PVA-GO Fiber Mats.

Electrospinning is a well-established method for the fabrication of polymer biomaterials, including those with core-shell nanofibers. The variability of structures presents a great range of opportunities in tissue engineering and drug delivery by incorporating biologically active molecules such as drugs, proteins, and growth factors and subsequent control of their release into the target microenvironment to achieve therapeutic effect. The object of study is non-woven core-shell PVA–PEG–SiO2@PVA–GO fiber mats assembled by the technology of coaxial electrospinning. The task of the core-shell fiber development was set to regulate the degradation process under external factors. The dual structure was modified with silica nanoparticles and graphene oxide to ensure the fiber integrity and stability. The influence of the nano additives and crosslinking conditions for the composite was investigated as a function of fiber diameter, hydrolysis, and mechanical properties. Tensile mechanical tests and water degradation tests were used to reveal the fracture and dissolution behavior of the fiber mats and bundles. The obtained fibers were visualized by confocal fluorescence microscopy to confirm the continuous core-shell structure and encapsulation feasibility for biologically active components, selectively in the fiber core and shell. The results provide a firm basis to draw the conclusion that electrospun core-shell fiber mats have tremendous potential for biomedical applications as drug carriers, photocatalysts, and wound dressings.

Modeling and simulation of tensile properties of r-LDPE/GSF composite using the response surface methododology

Abstract In this study, the ultimate tensile strength (UTS), elongation (ELG) and tensile modulus (TEM) of a recycled low-density polyethylene groundnut shell fiber composite (r-LDPE/GSF) were modeled and simulated when considered particle size (PS) and fiber content (FC) of groundnut shell fiber (GSF) by applying response surface techniques (RSM) for structural application. The deposit of recycled low-density polyethylene (r-LDPE) and GSF, an agro-waste, were combined in the production of r-LDPE/GSF composite at PS of 50–70 mesh (300–212 µm) and FC of 10–30 wt% of the GSF. The manufactured r-LDPE/GSF composite was tested for UTS, ELG and TEM and optimized by considering these process variables of GSF, PS and FC with RSM. The outcome indicated that at optimum condition, the UTS, ELG and TEM were 8.5072 MPa, 12.83% and 0.94007 GPa, respectively. The parameters at this point were PS and FC of 60.48 mesh (250 µm) and 30 wt%, respectively. The coefficient of determination (R 2) was close to 0.99. The percentage of relative errors between raw experimental reading and the RSM was <0.16. Based on the result of the work, the predicted RSM data on tensile properties of r-LDPE/GSF composite shows that is a potential engineering material for structural application.

Natural Fiber Composites from Coconut Fiber, Wood Powder, and Shellfish Shell of Centrifugal Clutch Materials

Natural fiber materials are the sustainable sources used for future automotive elements, where the centrifugal clutch utilizes the frictional force on the clutch pads to transfer kinetic energy from the rotating crankshaft to the transmission and the wheels. These pads are produced from several natural composites, such as coconut fiber, as well as wood and shellfish powder, whose characteristics are being investigated for hardness, microstructure, and wear properties. Based on this study, performance analysis was carried out on the samples of composite centrifugal clutch applied to automatic motorcycles. As a comparison, subsequent analysis was conducted on the genuine clutch pad materials, where the results showed differences in the characteristics of each mixture composition of the natural fiber composites. This indicated that the addition of wood powder composition to the clutch pad increased the hardness and special wear values by an average of approximately 12.9 and 1.16%, respectively. Furthermore, the composite content was observed in the microstructure, as the maximum power and torque on the natural fiber materials were 10.7 hp and 17.17 N.m, respectively. The value was found to be closely similar to the genuine parts with maximum power and torque of 10.8 hp and 16.02 N.m, respectively.

Mechanical and optimization studies of polypropylene hybrid biocomposites

Towards developing a polymeric matrix characterized by high strength to cost ratio, polypropylene (PP) was hybridized with low-cost particulate snail shell (PSS) and kenaf fiber (KF) via compression moulding at 180 °C and 0.2 MPa. The developed composites were grouped into three and labeled as mix 2, 4, and 10. Each group entailed the blend of 5, 10, 20, and 30 wt% KF with 2, 4, 10 wt% PSS respectively. From the results, it is observed that the hardness value was enhanced by the blend of 5 to 30 wt% KF and 2, 4, and 10 wt% PSS. However, 2 wt% PSS mix with 5 to 30 wt% KF resulted in progressive improvement in impact, compressive, flexural, and tensile strengths values. The 4 wt% PSS yielded consecutive increase in impact, compressive and flexural strength when combined with 5 and 10 wt% KF. However, it was observed that subsequent addition of 20 and 30 wt% KF led to a marginal reduction in the strength values. The tensile strength attained optimum value when 4 wt% PSS was commixed with 30 wt% KF. Conversely, the combinations of 10 wt% PSS with 5, 10, 20, and 30 wt% KF had no significant improvement to the mechanical properties of PSS/KF-bio-PP composite (except for hardness) siring strength decrease. Taguchi optimization revealed that the collage of 4 wt% PSS and 10 wt% KF presented optimum mix for hybrid bio-PP composite.