Fibrous Sheets Research Articles

Air‐laid and foam‐laid nonwoven composites: The effect of carrier medium on mechanical properties

AbstractThermoplastic nonwoven composites were produced with the air‐laying and foam‐forming processes from cellulosic and plastic fibers. The two raw material combinations were (1) PP/PE (fiber length 3 mm), PP/PE (12 mm), fluff pulp fibers (2 mm) and (2) PP/PE (3 mm), fluff pulp fibers, viscose (10 mm). After forming, the fibrous sheets (400 gsm) were bonded with heat pressing (145°C). The effect of the carrier medium, air or aqueous foam, on the tensile and impact properties and sheet structure was explored. The air‐laids differed from the foam‐laids by sheet anisotropy, density, and the lack of an additional bonding regime between wood fibers due to the dry forming process. The PP/PE bonding fibers gave the air‐laids a good capacity to elongate compared to the foam‐laids. The advantage was lost when nonbonding viscose was added. The impact strength was dependent on the PP/PE dosage and the sheet density, rather than the moisture‐induced bonding between wood fibers. The changing long/short fiber ratios caused gradual shifts in sheet properties, usually a reduction in a mechanical property as the share of short fiber increased in the mix. Economic analysis revealed that increasing fluff content can reduce raw material costs, providing a possibility for cost optimization in total production costs.

Fabrication and characterization of calcium lactate gluconate electrospun novel fibrous sheet for bone tissue engineering

Fabrication and characterization of calcium lactate gluconate electrospun novel fibrous sheet for bone tissue engineering

Discernment of synergism in co-pyrolysis of starch, lignin, and cellulose: Properties and reactivity of char production

Starch, lignin, and cellulose are selected as representatives of solid waste, and the effects of these three main components and their interactions on the characteristics of the corresponding pyrolysis char are researched. The findings indicate that the interaction between starch (0.0216 min−1) and lignin (0.0203 min−1) could result in a lower oxidation reaction rate (0.0172 min−1) of the pyrolysis of their char mixture, which is associated with a slight collapse of the fibrous sheet structure. According to the comparison of the crystalline phases identified by X-ray diffractometry research, the interaction between lignin and cellulose improves the degree of carbon ordering, leading to the presence of C-faces (100) in the lignin + cellulose char sample. Raman analysis explains that the interaction between starch and lignin results in increased size and thickness of graphitic domains, and a similar trend is observed in the starch and cellulose char samples. Conversely, the band area ratio ID4/IG values of the mixed char samples are comparable to those of the two corresponding single-component char samples, indicating that no interaction occurs in the sp2–sp3 mixed structures. The results indicate that the carbon conversion increases with increasing temperature. Otherwise, the interaction between lignin and cellulose improves the degree of carbon ordering. The results of this study are anticipated to contribute to a better understanding of the mechanisms involved in the interactions of waste components on char production by pyrolysis of solid wastes.

Isolated Traumatic Sutural Diastasis in a Young Adult: A Case Report

The bony calvarium protects the most vital organ of our body.The skull is composed of various bones united by a zigzag line called sutures.The fusion of these sutures creates the protective calvarium of the brain.In addition to protection, this suture line helps during parturition. When the anterior and posterior fontanelle attaches via a fibrous sheet, it has a favorable shape during vaginal delivery and helps in the development of the brain.The suture fuses with the adjacent bones at certain ages and creates a protective calvarium.During this period, suture diastasis occurs due to various causes, such as RTA, falls, and increased intracranial pressure.It is usually associated with an additional fracture line; however, under

A novel biomimetic nanofibrous cardiac tissue engineering scaffold with adjustable mechanical and electrical properties based on poly(glycerol sebacate) and polyaniline

Biomaterial tissue engineering scaffolds play a critical role in providing mechanical support, promoting cells growth and proliferation. However, due to the insulation and inappropriate stiffness of most biomaterials, there is an unmet need to engineer a biomimetic nanofibrous cardiac tissue engineering scaffold with tailorable mechanical and electrical properties. Here, we demonstrate for the first time the feasibility to generate a novel type of biocompatible fibrous scaffolds by blending elastic poly(glycerol sebacate) (PGS) and conductive polyaniline (PANI) with the help of a nontoxic carrier polymer, poly (vinyl alcohol) (PVA). Aligned and random PGS/PANI scaffolds are successfully obtained after electrospinning, cross-linking, water and ethanol wash. Incorporating of different concentrations of PANI into PGS fibers, the fibrous sheets show enhanced conductivity and slower degradation rates while maintaining the favorable hemocompatibility. The elastic modulus of the PGS/PANI scaffolds is in the range of 0.65–2.18 MPa under wet conditions, which is similar to that of natural myocardium. All of these fibrous mats show good cell viability and were able to promote adhesion and proliferation of H9c2 cells. Furthermore, the in vivo host responses of both random and aligned scaffolds confirm their good biocompatibility. Therefore, these PGS/PANI scaffolds have great potential for cardiac tissue engineering.

Experimental determination of in-plane permeability of nonwoven thin fibrous materials

Knowledge of hydraulic properties is crucial for understanding and modeling fluid flow in thin porous media. In this work, we have developed a new simple custom-built apparatus to measure the intrinsic permeability of a single thin fibrous sheet in the in-plane direction. The permeability was measured for two types of nonwoven thin fibrous porous materials using either the water or gas phase. For each layer, the measurements have been done for different combinations of flow direction and fiber orientation. The permeability values measured using gas and water were approximately close to each other. The permeability of the two samples was found to be anisotropic and the principal permeabilities were determined based on the measurements.

CO2 adsorption and CO2/CH4 separation using fibrous amine-containing adsorbents: isothermal, kinetic, and thermodynamic behaviours.

A series of fibrous aminated adsorbents for CO2 adsorption were prepared by covalent incorporation of poly (glycidyl methacrylate) (PGMA) by graft copolymerization of GMA onto electron beam (EB) irradiated polyethylenepolypropylene (PE/PP) fibrous sheets and subsequent amination with ethylenediamine (EDA), diethylenetriamine (DETA), or tetraethylenepentamine (TEPA). The physico-chemical properties of the adsorbents were evaluated using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric (TGA), X-ray diffraction (XRD), and Brunauer-Emmett-Teller (BET) analysis. All the adsorbents displayed typic primary and secondary amine features combined with a decrease in both of crystallinity and surface area of PE/PP, and such a decrease was higher in adsorbents with longer aliphatic chain of the amine. Of all adsorbents, TEPA-containing fibres showed the highest CO2 adsorption capacity and thus was further investigated for CO2 capture from CO2/CH4 mixtures of different gas ratios under various pressures and temperatures. The selectivity of CO2 over CH4 and equilibrium isotherms, kinetics, and thermodynamics of the adsorption on the fibrous aminated adsorbent were all investigated. The Sips model was found to best fit the isotherm of CO2 adsorption suggesting the presence of a combination of monolayer and multilayer adsorptions. The adsorption kinetic data was found to best fit Elovich model reflecting chemisorption. The ΔG°, ΔS°, and ΔH° showed positive values suggesting that the adsorption of CO2 on the present fibrous adsorbent was non-spontaneous with an increase in randomness implying that the process was endothermic. Overall, it can be suggested that PE/PP-g-PGMA/TEPA adsorbent has a strong potential for separation of CO2 from NG.

Acoustic scattering analysis in a lined waveguide involving step-discontinuities with generalized planar boundaries

Analyzing the attenuation of unwanted sound in waveguides or ducts has led to many complex, interesting and challenging problems for engineers and researchers. The underlying article looks at the scattering properties of a lined waveguide in a broader context. An incident wave is introduced through region . The inlet of the waveguide is situated symmetrically whereas, the outlet of waveguide is acoustically lined including step-discontinuities and generalized mixed boundaries. The effects of various porous lined materials, such as fibrous and perforated sheets, are taken into account to analyze the transmitted behavior of the waveguide structure. The mode-matching method (MMM) is used to determine each region's scattered field potentials. The resulting energy functions of distributed fields are constructed both with and without structural discontinuities, as well as by varying the channel size in accordance with various physical parameters. In a specific situation, the current results of the theory of waveguides are restored, which leads to the presentation of a number of new results. It has been established that the resulting solution satisfies all geometric requirements, the law of conservation of energy, mathematical representation and graphics.

Enhancement of carbon dioxide adsorption performances by hydrazinolysis of poly(n-vinylformamide) grafted fibrous adsorbent

Abstract Emission of carbon dioxide (CO2) becomes a main concern in battling issues of global warming. The strategy to reduce the concentration of CO2 could be achieved by implementing carbon capture and storage (CCS) technology such as adsorption by solid adsorbents. In this work, hydrazone containing adsorbent was prepared by radiation induced grafting of N-vinylformamide (NVF) onto polyethylene coated polypropylene (PE/PP) fibrous sheets and subsequent hydrazinolysis for CO2 capture. Hydrazinolysis of the amide group to hydrazone moieties was accelerated by the addition of ammonium salts. These newly prepared adsorbent was characterized by scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR). The adsorption tests of pure CO2 and N2, and their mixture were carried using the gravimetric method. The result revealed that the obtained adsorbent was highly CO2 selective and attained remarkably higher CO2 sorption capacity of 3.1 mmol/g at 30 bar and room temperature compared to 0.3 mmol/g for amide-containing sample. The new adsorbent could be used for few repeated cycles with negligible loss in sorption capacity. Overall, the hydrazone-containing adsorbent has storing potential for CO2 capture, and more studies need to be conducted for further development.

Effect of amine head group imparted to poly (glycidyl methacrylate) grafted fibrous adsorbent for CO2 adsorption

Abstract The demand to develop adsorbents for CO2 capture with high performance continued to grow extensively. Adsorbents with covalently bonded amine groups based on fibrous substrate modified by radiation-induced grafting copolymerization (RIGC) of glycidyl methacrylate (GMA) and amination treatment have emerged recently. In this study, GMA was grafted onto a polyethylene/polypropylene (PE/PP) fibrous sheet and the grafted intermediate was used to incorporate two different amine-containing agents, namely polyethyleneimine (PEI) and ethylenediamine (EDA) for CO2 adsorption. The chemical structural and morphological changes in the two aminated adsorbents were evaluated using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. A low and equal amination level of 20% was achieved in PEI-containing and EDA-containing adsorbents. The CO2 adsorption from a binary mixture of CO2/N2 (40:60 v/v) was not satisfactory despite a 30% higher adsorption capacity (50.44 mg/g) demonstrated by EDA-containing adsorbent compared to 34.51 mg/g for PEI-containing counterpart at 30 bar and at room temperature. More work is needed to elevate the CO2 adsorption capacity levels in such adsorbents by increasing the amination level via optimization of reaction parameters.

Fabrication of Enzyme-Loaded Cartridges Using CO2-Assisted Polymer Compression

An enzyme-loaded disk-shaped cartridge was fabricated using CO2-assisted polymer compression (CAPC), which is a polymer-bonding method that does not use heat. In this process, after the enzyme was loaded onto mesoporous silica, it was placed in a container fabricated from laminated fibrous sheets using CAPC. Subsequently, the lid and container were bonded via CAPC. Verification using the reductive decomposition reaction of an azo dye (methyl red) showed that the enzyme was not deactivated and that a reaction cartridge was created successfully.

Effects of Precursors and Carbon Nanotubes on Electrochemical Properties of Electrospun Nickel Oxide Nanofibers-Based Supercapacitors.

Supercapacitors have been considered as one of the main energy storage devices. Recently, electrospun nanofibers have served as promising supercapacitor electrodes because of their high surface area, high porosity, flexibility, and resistance to aggregation. Here, we investigate the effects of electrospinning parameters and nickel precursors on the nanostructure of electrospun nickel oxide (NiO), as well as on their electrochemical performance as supercapacitor electrodes. In contrast to the case of using nickel nitrate, increasing the nickel acetate molar concentration maintains the flexible fibrous sheet morphology of the as-spun sample during the polycondensation and calcination of NiO. As a result, our flexible electrode of NiO nanofibers derived from nickel acetate (NiO-A) exhibits much better electrochemical performance values than that of nickel nitrate-derived NiO. To further improve the electrochemical storage performance, we combined NiO-A nanofibers with single-walled carbon nanotubes (CNTs) as a hybrid electrode. In both half-cell and full-cell configurations, the hybrid electrode displayed a higher and steadier areal capacitance than the NiO-A nanofibers because of the synergetic effect between the NiO-A nanofibers and CNTs. Altogether, this work demonstrates the potency of the hybrid electrodes combined with the electrospun NiO-A nanofibers and CNTs for supercapacitor applications.

A comparative study to analyze the effect of planter fascia stretch and heel pad with moist heat in the patients of planterfascitis

This study investigated the effect of planter fascia stretch and heel pad with moist heat in the patients of planterfascitis among subjects aged 20-40. Planter fascia is a thickened fibrous sheet of connective tissue which begins from medial tubercle on undersurface of calcaneus and fans out joining to the metatarsophalangeal joints plates to form longitudinal foot arch.

Design of the Prototype of Contact Drawing Device for Potential Individual Therapeutic Fiber Formation Purposes.

Pharmaceutical compounding enables the preparation of unlicensed medicine to meet specific patient needs that do not have a licensed medicine available on the market. It must be performed in the best possible circumstance by certified pharmacists using validated standard operating procedures to obtain the highest quality medicinal product. The various spinning techniques provide drug delivery systems easily adapted to individual patient’s needs among the emerging technologies. The primary purpose of the present work was to introduce the prototype of a contact drawing device for the compounding of drug delivery systems for individual in-patient needs. The preliminary experiments resulted in oriented fibers of micrometer diameter range. The device can be placed in controlled conditions and could provide drug-loaded fibrous sheets for further treatments assuring the individual patient’s medicine need of the required quality.

Superhydrophobic Poly(l-lactic acid) Membranes with Fish-Scale Hierarchical Microstructures and Their Potential Application in Oil–Water Separation

In this work, superhydrophobic poly(l-lactic acid) (PLLA) hierarchical membranes exhibiting excellent oil-removal performance, which is of great importance in curbing the oil-pollution environment, were fabricated by a simple solvent-evaporation-induced precipitation method. PLLA membranes with hierarchical micro/nanostructures (fish scales, fibrous sheets, and petal-like morphology) can be conveniently prepared by adjusting the preparation parameters including PLLA concentration, precipitation temperature, type of solvent and nonsolvent, and the addition of nano-SiO2. The results show that the water contact angle of the fish-scale-structured PLLA membrane was 138.6°, revealing that water repellency was significantly improved compared to that of the solvent-casting PLLA membrane (∼72.8°). Moreover, the PLLA/SiO2 nanocomposite membrane with a dense hierarchical micro/nanostructure had a water contact angle greater than 167.1°, which has great potential in oil-water separation.

Supramolecular Assembly of Hybrid Pt(II) Porphyrin/Tomatine Analogues with Different Nanostructures and Cytotoxic Activities.

A simple strategy for synthesizing supramolecular hybrids was developed for the preparation of bioavailable nanohybrid photosensitizers by assembling visible-light-sensitive Pt(II) meso-tetrakis(4-carboxyphenyl)porphyrinporphyrin (PtTCPP)/tomatine analogues. The hybrids were self-assembled into nanofibrous or nanosheet structures approximately 3–5 nm thick and several micrometers wide. α-Tomatine generated a unique fibrous vesicle nanostructure based on intermolecular interactions, while dehydrotomatine generated nanosheet structures. Nanoassembly of these fibrous vesicles and sheets directly affected the properties of the light-responsive photosensitizer for tumor photodynamic therapy (PDT), depending on the nanostructure of the hybrid PtTCPP/tomatine analogues. The cytotoxicity of PtTCPP to cancer cells under photoirradiation was significantly enhanced by a tomatine assembly with a fibrous vesicle nanostructure, attributable to increased incorporation of the drug into cells.

Features of a simvastatin-loaded multi-layered co-electrospun barrier membrane for guided bone regeneration.

A novel tri-layer membrane consisting of polycaprolactone (PCL) fibrous sheets and structured nanofibers with a gelatin (Gt) shell and a simvastatin-containing PCL core (PCL-Gt/PCL-simvastatin membrane) was prepared. The soft external layer comprised of Gt/PCL-simvastatin, the external layer of PCL and the middle layer of both microfilaments, interwoven together. The membrane was designed to promote osteoinduction and act as a barrier against cells but not against water and molecules in order to promote guided bone regeneration. The structure of the membrane was characterized by scanning electronic microscopy. The in vitro release rates of simvastatin over 32 days were determined by high-performance liquid chromatography. For in vitro biological assays, bone marrow mesenchymal stem cells and human fibroblasts were cultured on the different surfaces of the membrane. Cell adhesion, proliferation, distribution, and differentiation were examined. For in vivo testing, cranial defects were created in rabbits to assess the amount of new bone formed for each membrane. The results revealed that membranes with multi-layered structures showed good cell viability and effective osteoinductive and barrier properties. These results suggest that the novel multi-layered PCL-Gt/PCL-simvastatin membranes have great potential for bone tissue engineering.

Mechanical characterization of surface wrinkling properties in fibrous sheet materials by facile folding process

Wrinkling and folding are crucial morphological and structural motifs in polymeric sheet materials. In this study, a simultaneous-mechanical test method was proposed to evaluate the wrinkling behaviour by simply constructing the folding deformations of fibrous sheet materials. The internal relationship between fabric folding and wrinkling was studied, and the similar power law relation of the wrinkling force and the number of folded layers between wrinkling and folding of fabrics was experimentally proved. This leads to a view of wrinkling from a hierarchical folding process, laying down the way to describe the disordered wrinkling by a facile folding test. The proposed test method and instrument can simulate the complex deformation and mechanical action during the wrinkling process by curve parameters extracted from the measured force-displacement curve. The correlation analysis between the curve parameters and wrinkling grades of subjective evaluation was conducted. Moreover, the prediction model of wrinkling grades was constructed and validated to give a direct overall evaluation of wrinkling grades for industrial application. The evaluation results of the prediction model based on the proposed mechanical test method showed good agreement with the traditional subjective evaluation results, which indicated that the designed method and instrument provided a feasible and effective measurement using a facile folding process for the surface wrinkling properties of fibrous sheet materials, enhancing our design and tuning capability for the morphology instability and wrinkling of fibrous sheet materials.

Studies on Sodium Lauryl Sulphate-supported Thorium (IV) Phosphate: A New Surfactant-supported Cation Exchange Resin, Useful in Water Purification

Background: With the increasing population and decreased quality of drinking water, new materials and methods for the purification of water need to be developed. This study aims to present a solution from pollution by proposing the synthesis method of sodium lauryl sulphate (SLS)-supported thorium (IV) phosphate (ThP), its characterisation and disquisition of analytical applications by executing dual separations of calcium. Methods: SLS ThP was synthesised by the sol-gel method. The synthesised exchanger was characterised by physicochemical methods, such as powdered X-ray diffraction, scanning electron microscopy, thermo-gravimetric-differential thermal analysis, EDAX and Fourier transform-infrared study. Also, its competency towards the ion exchange processes and in analytical chemistry was verified. Results: The prominent characteristic of SLS-supported ThP was its high ion exchange capacity for sodium ions (3.10 meq/g), which is almost 2.5 times more than the exchange capacity of ThP, i.e., 1.3 meq/g. The material resulted in a fibrous sheet that is thermally and mechanically stable but poorly crystalline and shows selectivity towards Ca2+ and Hg2+ ions. Conclusion: The synthesised cation exchange material is thermally stable, showing drastically high exchange capacity and selectivity towards Hg2+ and Ca2+ metal ions, which might be because of the use of an anionic surfactant, SLS, while the synthesis of ThP plays a key role in enhancing the exchange capacity and adsorption of specific metals. Therefore, based on the results obtained, the above-said materials have applications in water purification processes and environmental pollution control where removal of Hg2+ and Ca2+ is essential.

Hybrid silk fibroin–gelatin nanofibrous sheet for drug delivery and regenerative medicine: In‐vitro characterization and controlled release of simvastatin/protein

Blend drug‐loading method in electrospun scaffolds has gained much attention as a cost‐effective and simple delivery system in regenerative medicine. However, it has some drawbacks, such as the burst release of encapsulated drugs and denaturing active agents in harsh organic solvents. In this study, a new silk fibroin‐gelatin (SF–G) fibrous sheet has been introduced as an engineered scaffold and a straightforward drug delivery system for skin tissue engineering applications. The hybrid sheets have been prepared via co‐electrospinning and in‐situ crosslinking methods without corrosive solvents and toxic crosslinking agents. To evaluate the proposed scaffold as a controlled release system, the simvastatin (SIM), a poorly water‐soluble drug, and bovine serum albumin (BSA), a hydrophilic protein, have been selected as two model pharmaceutical ingredients. The physicochemical and mechanical properties, as well as the degradation profile of the hybrid sheets, indicate that the fabrication method, SF: G fibers volume ratio and degree of crosslinking are vital in controlling the different features of the prepared scaffolds. The obtained results demonstrate that the hybrid structure, type of fiber, and in‐situ crosslinking method provide an opportunity to adjust the release kinetics of encapsulated drug/protein within the fiber matrix. The in‐vitro analysis also demonstrates suitable bioactivity of the drug/protein‐loaded scaffolds. Therefore, this hybrid nanofibrous sheet may be considered a new candidate for biomedical applications and pharmaceutical science.