Showing papers in "Fibers and Polymers in 2017"
TL;DR: A good demonstration of the applicability of chitosan nanoparticles as an effective antimicrobial agent with antibiofilm activity as well is demonstrated.
Abstract: The present investigation describes the synthesis and characterization of novel biodegradable nanoparticles based on chitosan for biomedical applications. The presence of primary amine groups in repeating units of chitosan grants it several properties like antibacterial activity, antitumor activity and so on. Chitosan forms nanoparticles spontaneously on the addition of polyanion tripolyphosphate which has greater antimicrobial activity than parent chitosan. In the present study, chitosan nanoparticles (ChNP) were prepared by the ionic gelation method. The physiochemical characteristics of nanoparticles were analyzed using XRD, SEM, FTIR. The antibacterial activity of chitosan nanoparticles against medical pathogens Klebsiella pneumoniae, Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa was evaluated by calculation of minimum inhibitory concentration (MIC) and compared with chitosan and chitin activity. The mode of action and factors affecting antibacterial activity were also analyzed. ChNP compounds exhibited superior antimicrobial activity against all microorganisms in comparison with chitosan and chitin. The antibiofilm activity was studied using crystal violet assay and growth on congo red agar. The study is thus a good demonstration of the applicability of chitosan nanoparticles as an effective antimicrobial agent with antibiofilm activity as well.
210 citations
TL;DR: In this paper, a study on the tensile and flexural properties of jute-glass-carbon fibers reinforced epoxy hybrid composites in inter-ply configuration is presented.
Abstract: A study on the tensile and flexural properties of jute-glass-carbon fibers reinforced epoxy hybrid composites in inter-ply configuration is presented in this paper. Test specimens were manufactured by hand lay-up process and their tensile and flexural properties were obtained. The effects of the hybridization, different fibers content and plies stacking sequence on the mechanical properties of the tested hybrid composites were investigated. Two-parameter Weibull distribution function was used to statistically analyze the experimental results. The failure probability graphs for the tested composites were drawn. These graphs are important tools for helping the designers to understand and choose the suitable material for the required design and development. Results showed that the hybridization process can potentially improve the tensile and flexural properties of jute reinforced composite. The flexural strength decreases when partial laminas from a carbon/epoxy laminate are replaced by glass/epoxy or jute/epoxy laminas. Also, it is realized that incorporating high strength fibers to the outer layers of the composite leads to higher flexural resistance, whilst the order of the layers doesn’t affect the tensile properties.
70 citations
TL;DR: In this article, a starch-based composite film was prepared by using fibrous residual of starch extraction (cassava bagasse) as filler, and the physical, thermal, tensile and structural properties of the composite film were investigated.
Abstract: A starch-based composite film was prepared by using fibrous residual of starch extraction (cassava bagasse) as filler. Composite films were prepared through casting technique using fructose as a plasticizer and various sizes and concentrations of bagasse. The physical, thermal, tensile and structural properties of the composite film were investigated. Also, temperature variation of dynamic-mechanical parameters of cassava starch/bagasse composites was investigated by Dynamic Mechanical Analysis (DMA) test. The size and concentration of bagasse were significantly influenced the physical properties of cassava bagasse. There were also increases- in thickness, water solubility, and water absorption of cassava bagasse. There were reduction of water content and density of the film. However, there was no significant effect of adding bagasse on thermal properties. X-ray diffraction (XRD) studies indicated increase in crystallinity of the composites with increase in fiber content. SEM micrographs indicated that the filler was incorporated into the matrix. Films with a small size of bagasse showed better compact structure and homogeneity surface. On the other hand, films with big size and higher concentration of bagasse exhibited more heterogeneous surfaces. The modulus and maximum tensile strength of composite films were increased from 69.03 to 581.68 MPa and 4.7 to 10.78 MPa respectively. Addition of 6 % bagasse was the most efficient reinforcing agent owing to its remarkable physical and mechanical properties. The composites prepared by using cassava for both matrix and reinforcement increased the significance of the remaining residue of starch extraction.
62 citations
TL;DR: In this paper, a superhydrophobic cellulose and chitosan composite aerogel (SCECS) is fabricated through a novel and simple approach for the first time.
Abstract: Superhydrophobic cellulose and chitosan composite aerogel (SCECS) is fabricated through a novel and simple approach for the first time. During the preparation of cellulose and chitosan composite aerogel (CECS), chitosan is selfassemble into number micron-diameter particles on the surface of aerogel, which is similar to the micromorphology of a lotus leaf. Based on the rough surface, CECS is modified by sodium stearate through electrostatic interaction and ion exchange. Water contact angles of 156° are obtained for superhydrophobic aerogel. SCECS can remove various oils from water and with absorption capacities of 10 g/g for oil. Furthermore, the special structure of a non-porous of surface and porous layer of internal is benefit to separate surfactant-stabilized water-in-oil emulsions under gravity.
57 citations
TL;DR: In this article, the effects of silane treatment on hybrid composites were investigated by fourier transform infrared spectroscopy (FTIR) and found very effective peaks, which can be utilized to produce components for building structure, materials and automobile applications.
Abstract: In this work, hybrid composites were fabricated by hand layup method to hybridize treated Pineapple leaf fibre (PALF) and kenaf fibre (KF) in order to achieve superior mechanical properties on untreated hybrid composites. Silane treated PALF/KF phenolic hybrid composites were prepared on various fibre fraction to investigate mechanical properties and compared with untreated PALF/KF phenolic hybrid composites. The effects of silane treatment on hybrid composites were investigated by fourier transform infrared spectroscopy (FTIR) and found very effective peaks. Effects of treated hybrid composites were morphologically investigated by using scanning electron microscopy images and analysed the tensile results. Treated PALF/KF phenolic hybrid composites enhanced the flexural strength, modulus, impact strength and energy absorption while tensile strength and modulus decreased. The overall performances of 70 % PALF 30 % Kenaf hybrid composites were improved after silane treatment. Silane treatment of fibres improved the mechanical performance of hybrid composites and it can be utilized to produce components for building structure, materials and automobile applications.
47 citations
TL;DR: In this paper, the first report of using biomordants with prina extract as a possible substitute for environmentally unfavourable metallic mordants was presented in terms of cost and consumption efficiencies.
Abstract: The current study is the first report of using biomordants with prina extract as a possible substitute for environmentally unfavourable metallic mordants. As a part of sustainable and cleaner production approach, eco-friendly natural dyeing conditions were presented in terms of cost and consumption efficiencies. A novel and renewable natural dye source prina is an essential by-product of olive oil production. This biomass was valorized in wool dyeing in conjunction with biomordants namely powder of iris germanica (I. Versicolor), valex (acorn of Quercus ithaburensis ssp.macrolepis), pomegranate (Punica granatum L.) rind, rosemary (Rosmarinus officinalis), and thuja (thuja orientalis). Their color coordinates and fastness properties were compared and assessed versus metallic mordants. Prina extract itself without mordant has a fair light fastness of 3 and an excellent washing fastness of 4-5 both for color change and bleeding. Valex, pomegranate rind, iris, rosemary, and thuja leaves were proposed as promising alternatives to alum, iron II sulfate, copper II sulfate, stannous chloride, and potassium dichromate. Biomordants generated significant color yield increment and exhibited equivalent fastness properties to metallic mordants. Water, energy, dye, chemical cost, and consumption of natural and synthetic dyeings on the basis of mill conditions were also calculated and compared mutually. Total recipe cost and chemicals/auxiliary consumption of natural dyeing are on average significantly less than with synthetic dyeing. Considerable savings are possible with natural dyeing, especially one-bath, in terms of cost, time, and consumption.
47 citations
TL;DR: In this paper, a woven fabric Kenaf/Kevlar hybrid yarn composite was fabricated with total fiber content of 40 % and 60 % of Epoxy as the matrix for composite fabrication and the results indicated there is a potential combination of natural fiber with synthetic fiber that can be fabricated as composite material for the application of high performance product.
Abstract: Woven Kenaf/Kevlar Hybrid Yarn is the combination of natural and synthetic fibers in the form of thread or yarn. The yarn is weaved to form a fabric type of fiber reinforced material. Then, the fabric is fabricated with epoxy as the resin to form a hybrid composite. For composite fabrication, woven fabric Kenaf/Kevlar hybrid yarn composite was prepared with vacuum bagging hand lay-up method. Woven fabric Kenaf/Kevlar hybrid yarn composite was fabricated with total fiber content of 40 % and 60 % of Epoxy as the matrix. The fiber ratios of Kenaf/Kevlar hybrid yarn were varied in weight fraction of 30/70, 50/50 and 70/30 respectively. The composites of woven fabric Kenaf/Epoxy and woven fabric Kevlar/Epoxy were also fabricated for comparison. The mechanical properties of five (5) samples composites were tested accordingly. Result has shown that of value of strength and modulus woven fabric Kenaf/Kevlar Hybrid Yarn composite was increased when the Kevlar fiber content increased. Therefore, among the hybrid composite samples result showed the woven fabric Kenaf/Kevlar Hybrid Yarn composites with the composition of 30/70 ratio has exhibited the highest energy absorption with 148.8 J which 28 % lower than Kevlar 100 % sample. The finding indicated there is a potential combination of natural fiber with synthetic fiber that can be fabricated as the composite material for the application of high performance product.
46 citations
TL;DR: In this article, the effect of fibre content on mechanical and morphological properties and thermal stability of roselle fibres (RFs) reinforced polyurethane (TPU) composites was studied.
Abstract: The aim of this paper is to study the effect of fibre content on mechanical and morphological properties and thermal stability of roselle fibres (RFs) reinforced polyurethane (TPU) composites. The RF/TPU composites were prepared at difference fibre contents; 10, 20, 30, 40 and 50 wt% by melt mixed mixer and hot press at 170 °C. Mechanical (tensile, flexural and impact strength) and Thermogravimetric analysis (TGA) properties of RF/TPU composites were measured according to ASTM standard. Obtained results indicated that effect of fibre contents display improved tensile and flexural and impact strength properties. RF/TPU composites show the best mechanical and thermal properties at 40 wt% roselle fibre content. Scanning electron microscopy (SEM) micrograph of fractured tensile sample of the roselle composite revealed good fibre/matrix bonding. TGA showed that RF/TPU with difference fibre contents had improved thermal stability.
43 citations
TL;DR: A sustainable nanocomposite from chitosan, silk fibroin and hydroxyapatite was investigated as adsorbent for organic dyes removal from waste water as discussed by the authors.
Abstract: Sustainable nanocomposite from chitosan, silk fibroin and hydroxyapatite was investigated as adsorbent for organic dyes removal from waste water. Chitosan/silk fibroin bioactive blend initiated successfully the mineralization of hydroxyapatite rod-like crystals with ~40 nm diameter. The formed nanocomposite was applied for methylene blue (MB) removal from waste water. The adsorption kinetics were fitted with Pseudo-second order kinetic model. Adsorption results well fitted to the Langmuir model and showed maximum adsorption capacity 476 mg/g. The current nanocomposite is sustainable and efficient adsorbent for organic dyes removal from waste water.
40 citations
TL;DR: In this paper, the effect of calcium carbonate (CaCO3) nanoparticles on the barrier properties and biodegradability of polylactic acid (PLA) was investigated, and the results suggested PLA nanocomposites as favorable candidates for food packaging applications.
Abstract: In this study, the effect of calcium carbonate (CaCO3) nanoparticles on the barrier properties and biodegradability of polylactic acid (PLA) was investigated. For this purpose, nanocomposite films with various CaCO3 nanoparticle contents (0, 3, 5, 10, and 15 wt%) were prepared by solution casting method. The gas permeability of nitrogen (N2), oxygen (O2), and carbon dioxide (CO2) was evaluated through a constant volume and variable pressure apparatus at different pressures and temperatures. According to results, barrier properties were improved by loading CaCO3 nanoparticles up to 5 wt%, and the gas permeability of CO2, O2, and N2 was decreased from 1.4, 0.31, and 0.07 Barrer to 0.48, 0.095, and 0.019 Barrer, respectively. In addition, it was also observed that the gas permeability of samples was decreased by increasing feeding pressure and increased by enhancing temperature. Furthermore, morphological results confirmed the formation of agglomerations and large clusters over 5 wt% CaCO3 nanoparticles. Finally, the thermal properties and biodegradability of PLA were increased by employing CaCO3 nanoparticles. These results suggested PLA nanocomposites as favorable candidates for food packaging applications.
39 citations
TL;DR: In this article, a polyacrylic acid-grafted quaternized cellulose (PAA-g-QC) was used for methylene blue adaption.
Abstract: A novel cellulose-based porous adsorbent with high adsorption capacity for methylene blue (MB) was prepared by free radical polymerization methods. The obtained polymer grafting rate and dye removal efficiency are as high as 338.64 % and 97.74 %, respectively, when the dosage of monomer is 4.5 g, the polymerization condition is 3 h at 70 °C. The cellulose-based adsorbent showed high mechanical properties and good flexibility. The Langmuir isotherm model revealed that the maximum theoretical adsorption capacity of this material for methylene blue was 1734.816 mg g-1 at pH 9.0 at 313 K, which is higher than the values observed for other adsorbents. Scanning electron microscopy (SEM) showed that the cellulose-based adsorbent exhibits a typical well-defined porous and interconnected three-dimensional framework structure, which is benefits to dye adsorption. The adsorption kinetics (pseudo first-order, pseudo-second-order, and intraparticle diffusion models) was also studied, and the pseudo-second-order model fitted MB adsorption better than the pseudo-first-order and intraparticle diffusion models at different initial dye concentrations (500-3000 mg l
-1). The novel polyacrylic acid-grafted quaternized cellulose (PAA-g-QC) adsorbent is thus potentially useful for the treatment of dye-contaminated wastewater.
TL;DR: Synthesize of a thermosetting resin based cardanol from cashew nut shell liquid (CSNL) using poly condensation process as composite matrix was carried out in this paper.
Abstract: Synthesize of a thermosetting resin based cardanol from cashew nut shell liquid (CSNL) using poly condensation process as composite matrix was carried out. Locally collected sugarcane bagasse fiber was dried in an oven to remove the moisture content. These fibers were then cut into specific average length of 10 mm and 20 mm and made into two different sets of cardanol based bio-composites of varying concentration of 0, 5, 10, 15 and 20 % by compression moulding process. The mechanical properties were evaluated by means of tensile, flexural and impact in addition to water absorption test. Results had shown the enhancement of the mechanical properties with increase in range of bagasse fiber upto 15 weight % in both the sets. Of the two sets, 20 mm length fiber possesses more strength comparatively.
TL;DR: In this article, a facile and cost effective method is presented for in-situ synthesis of cuprous oxide nanoparticles on polyester fabric along with surface modification by using one pot wet chemical method at boil.
Abstract: In this research, a facile and cost effective method is presented for in-situ synthesis of cuprous oxide nanoparticles on polyester fabric along with surface modification by using one pot wet chemical method at boil. Copper sulfate (CuSO4), sodium hypophosphite (SHP) and polyvinylpyrrolidone (PVP) were used as precursor, reducing agent and stabilizer, respectively. Further, monoethanolamine (MEA) was used as pH adjustment and also modifier of polyester surface introduced amide and hydroxyl functional groups on the fabric. The images of FESEM, mapping, patterns of EDX, UV-visible absorbance spectrum, FTIR analysis and X-ray diffraction pattern confirmed the successful processing. The treated samples showed excellent antibacterial properties (100 %) toward both Staphylococcus aureus and Escherichia coli pathogen bacteria. Also, the results of cytotoxicity test proved no harmful effects on the human dermal fibroblasts for the treated sample with the lower concentration of the materials having white color with good antibacterial activities. The treated samples also indicated very good UV protection properties as well as improved wettability and mechanical properties. They are also sensitive to ammonia through immediate color change when contacted with ammonia solution. The above mentioned processing method can be used for production of polyester fabric with multifunctional properties for using in the various textile industries.
TL;DR: In this article, an electrospun polyindole nanofibers were characterized with SEM, TEM, FTIR and BET surface areas measurements, and the results showed that the Cu(II) adsorption was feasible, spontaneous and endothermic.
Abstract: Polyindole nanofibers were prepared via electrospinning method using acetonitrile as solvent. The obtained electrospun polyindole nanofibers were characterized with SEM, TEM, FTIR and BET surface areas measurements. Adsorption experiments were carried out in batch sorption mode to investigate the effect of pH, contact time and diameter of polyindole nanofibers. The Cu(II) adsorption was highly pH dependent and the optimum pH was found to be 6. The maximum adsorption capacities for electrospun polyindole nanofibers and polyindole powders were 121.95 and 18.93 mg/g attained in 15 and 60 min, respectively. With the diameter of polyindole nanofibers increasing, the adsorption capacity slightly decreased. The adsorption isotherm data fitted well to the Langmuir isothermal model which indicates that the monolayer adsorption occurred. The kinetics data analysis showed that the adsorption process could be described by pseudo-second order kinetic model, suggesting a chemisorption process as the rate limiting step. Thermodynamic parameters ΔHo, ΔSo and ΔGo for the Cu(II) adsorption by polyindole nanofibers were calculated. The results showed that the Cu(II) adsorption was feasible, spontaneous and endothermic. Desorption results revealed that the adsorption capacity can remain up to 75 % after 10 times usage. The electrospun polyindole nanofibers would have promising application for removal of Cu(II) from wastewater treatment.
TL;DR: In this article, the authors used polypropylene (PP)/high-density polyethylene (HDPE) polyblends (80/20 wt.%) as matrices, which are then melt-blended with inorganic carbon fibers (CF) as reinforcement to form electrically conductive PP/HPE composites.
Abstract: This study uses polypropylene (PP)/high-density polyethylene (HDPE) polyblends (80/20 wt.%) as matrices, which are then melt-blended with inorganic carbon fibers (CF) as reinforcement to form electrically conductive PP/HDPE composites. Tensile test, flexural test, Izod impact test, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and X-ray diffraction (XRD) are performed to evaluate different physical properties of samples. A surface resistance and electromagnetic interference shielding effectiveness (EMI SE) measurements are used to evaluate the electrical properties of the PP/HDPE/CF composites. Test results show that an increasing content of carbon fibers results in an 18 %, 23 %, and 60 % higher tensile strength, flexural strength, and impact strength, respectively. SEM results show that carbon fibers break as a result of applied force, thereby bearing the force and increasing the mechanical properties of composites. DSC and XRD results show that the addition of carbon fibers causes heterogeneous nucleation in PP/HDPE polyblends, thereby increasing crystallization temperature. However, the crystalline structure of PP/HDPE composites is not affected. Surface resistivity results show that 5 wt.% of carbon fibers can form a conductive network in PP/HDPE polyblends and reduce the surface resistivity from 12×1012 ohm/sq to 4×103 ohm/sq. EMI SE results show that, with a 20 wt.% CF and a frequency of 2-3 GHz, the average EMI SE of PP/HDPE/CF composites is between -48 and -52 dB, qualifying their use for EMI SE, which is required for standard electronic devices.
TL;DR: In this paper, flax fibers were treated with an organic surface coating containing SiO2 nanoparticles and the results showed that the fibers surface was homogenized and that a better adhesion was reached because of the coating.
Abstract: This research is intended to improve the interface between the fibers and the matrix and limit water absorption of bio-based material thereby decreasing degradation of the composites when they are exposed to external environment such as high temperature and humidity. In this study, flax fibers were treated with an organic surface coating containing SiO2 nanoparticles. This coating was a dispersion of silica fume in epoxy. One composite was also made with raw fibers as reference as well as one sample of pure PLA. Flax fibers/PLA composites were manufactured by hot pressing by stacking 4 PLA films and 3 pieces of flax fabric. Morphology and dispersion of the coating on the fibers was observed by scanning electron microscopy (SEM), small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM). Accelerated ageing was carried out on the 3 materials by placing them in a 50 °C water bath until saturation to investigate the influence of the coating on water diffusion. Mechanical properties of the different composites were investigated by tensile (before and after conditioning) and short beam shear (SBS) testing in order to evaluate the impact of the coating on the interfacial properties of the materials. The results show that the fibers surface was homogenized and that a better adhesion was reached because of the coating. Coating the fibers also allowed the decrease in water uptake by more than 10 % and their protection during conditioning, preserving their mechanical properties.
TL;DR: In this article, the Delonix regia stem shell extract (DSE) was used for natural dyeing of mulberry silk fabric and qualitative antibacterial analysis was done by AATCC 147 method with excerpts from three different solvents both against S. aureus and E. coli bacteria.
Abstract: The use of natural dyes and natural finishes on textiles has become a matter of significant importance because of the increased environmental awareness to avoid some hazardous synthetic dyes and synthetic chemicals. The Delonix regia stem shells were extracted in distilled water methanol and ethanol solvents. Phytochemical analysis was carried out for the presence of bioactive chemical constituents such as saponin, terpenoid, flavonoid, glycoside, phenol and tannin using the standard procedure. All the tests showed positive for the presence of components except saponin in methanol and ethanol extract. The qualitative antibacterial analysis was done by AATCC 147 method with excerpts from three different solvents both against S. aureus (gram-positive) and E. coli (gram-negative) bacteria. Delonix regia stem shell extract (DSE) in distil water was used for natural dyeing of mulberry silk fabric. Pre-mordanting and post-mordanting of silk fabric were carried out using alum and myrobalan mordants. Treated fabrics showed a substantial increase in colour depth (K/S) and adequate wash, light and rubbing fastness properties without and with mordanted and dyed silk fabrics. Quantitative antibacterial analysis by AATCC 100 method was done on dyed silk fabric which showed very good resistance both against bacteria S. aureus and E. coli bacteria. Dyed silk fabric also showed good to very good ultraviolet (UV) protection property. The physicochemical composition of the untreated and without mordant treated silk fabrics were analysed by attenuated total reflection (ATR) Fourier transforms infrared (FTIR) spectroscopy, scanning electron microscope (SEM), energy dispersive spectrometry (EDS) and atomic absorption spectrophotometer (AAS). In addition to that wash, durability was also measured of dyed silk fabric for antibacterial and ultraviolet protection (UPF) properties according to AATCC 61 2A washing method.
TL;DR: In this paper, the effects of date palm leaf fiber (DPLF) content on the thermal and tensile properties; and morphology of compatibilized polyolefin ternary blend were investigated.
Abstract: This work investigated the effects of date palm leaf fiber (DPLF) content on the thermal and tensile properties; and morphology of compatibilized polyolefin ternary blend. Recycled polyolefin ternary blend consisting of low density polyethylene (RLDPE), high density polyethylene (RHDPE) and polypropylene (RPP) were fabricated at different parts per hundred resin (phr) of DPLF. Maleic anhydride grafted polyethylene (MAPE) was used as compatibilizer to enhance the adhesion between filler and polymer matrix. The composites were prepared using melt extrusion and tests samples were produced via injection molding process. Thermal conductivity results showed that as much as 11 % reduction in thermal conductivity was achieved with the incorporation of 30 phr DPLF. Highest tensile strength was observed with the incorporation of 10 phr DPLF. The elongation at break was reduced with the addition of DPLF due to impediment of chain mobility by the fillers. Initial degradation temperature increased with the addition of DPLF. Hence, it is concluded that DPLF can be used to develop green and thermally insulating composites. It is hoped that the present results will stimulate further studies on the thermally insulative materials based on natural fibers reinforced polymer composites for applications in the building industries.
TL;DR: The Ag NPs coating on the cotton fabric showed an excellent antibacterial function with an outstanding laundering durability and has potential applications in a wide variety of fields such as sportswear, socks, and medical textile.
Abstract: L-cysteine (Cys) and silver nanoparticles (Ag NPs) were successfully linked onto the cotton fabric surfaces. The Cys molecules were covalently linked to the cotton fibers via esterification with the cellulose hydroxyl groups, and the Ag NPs tightly adhered to the fiber surface via coordination bonds with the Cys thiol groups. As a result, the Ag NPs coating on the cotton fabric showed an excellent antibacterial function with an outstanding laundering durability. The bacterial reduction rates (BR) efficiency reached 100 % for Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). After 50 consecutive laundering cycles, the bacterial reduction rates (BR) against E. coli and S. aureus were maintained over 97 %. It has potential applications in a wide variety of fields such as sportswear, socks, and medical textile.
TL;DR: In this article, the influence of different silane coupling agents on the thermal and physical properties of epoxy-anhydride composite reinforced with basalt fiber was evaluated by differential scanning calorimetry and thermogravimetric analysis.
Abstract: This study evaluates the influence of different silane coupling agents on the thermal and physical properties of epoxy-anhydride composite reinforced with basalt fiber. The silane coupling agents were selected by their functional groups so that they could have different chemical interactions with the epoxy and anhydride curing agents. The thermal and degradation behavior of the composites with different fiber contents were evaluated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Through the evaluation of Tg and thermal degradation behavior of both systems, it was deduced that the silane coupling agents have a great influence on the thermal properties of the composites as well as interfacial improvement. Also, the tensile properties of the composites were systematically evaluated in order to further understand the effect of silane coupling agents on the interaction with basalt fiber and epoxy matrix.
TL;DR: In this paper, the SiO2/PMIA nanofiber membrane based Li/LiCoO2 cell exhibited more excellent cycling stability with capacity retention of 95 % after 50 cycles.
Abstract: The nanofiber membrane prepared by electrospinning has been widely applied in lithium-ion batteries. A powerful strategy for designing, fabricating and evaluating Poly-m-phenylene isophthalamide (PMIA) nanofiber membrane with SiO2 nanoparticles was developed by electrospinning in this paper. The morphology, crystallinity, thermal shrinkage, porosity and electrolyte uptake, and electrochemical performance of the SiO2/PMIA nanofiber membranes were investigated. It was demonstrated that the nanofiber membrane with 6 wt% SiO2 possessed notable properties, such as better thermal stability, higher porosity and electrolyte uptake, resulting in higher ionic conductivity (3.23×10-3 S·cm-1) when compared with pure PMIA nanofiber membrane. Significantly, the SiO2/PMIA nanofiber membrane based Li/LiCoO2 cell exhibited more excellent cycling stability with capacity retention of 95 % after 50 cycles. The results indicated that the SiO2-doped PMIA nanofiber membranes had a potential application as separator in high temperature resistance lithium-ion batteries.
TL;DR: In this article, Zirconium carbide (ZrC) films are deposited onto polyester fabric through magnetron sputtering, and the deposited films are then examined by using field scanning electron microscopy and energy dispersive X-ray spectroscopy.
Abstract: Zirconium carbide (ZrC) films are deposited onto polyester fabric through magnetron sputtering. The deposited films are then examined by using field scanning electron microscopy and energy dispersive X-ray spectroscopy. The photothermal conversion property, film thickness, infrared reflectance and transmittance, and thermal conductivity are also evaluated. The results show that the highest far-infrared emissivity of polyester fabric deposited with ZrC is 0.9379. The ZrC deposited samples showed a small increase in thermal conductivity with a difference of 0.0611W/m·K, and a higher photothermal conversion efficiency with a temperature increase of 27.5 °C in 100 s, when the thickness of the ZrC film is 1920 nm. These therefore indicate that coating fabrics with ZrC through magnetron sputtering is an environmentally friendly means to produce textiles with photo-thermal conversion and heat insulation properties.
TL;DR: It demonstrated that the new AgNW/PU nanoweb electrodes could perform properly as ECG electrodes, and, there was not a significant difference of HR and RR-intervals measured by the two different types of electrodes.
Abstract: This study aims to measure ECG signals by the AgNW/PU nanoweb electrodes, and, to compare with signals measured by the conventional Ag/AgCl electrodes. Finally, to investigate the usage potential of the AgNW/PU nanoweb as ECG textile electrodes. The ECG textile electrodes were fabricated, using the polyurethane (PU) nanoweb (Pardam, s.r.o., Czech Republic) coated with 1 wt% of silver nanowires (AgNW) dispersed in ethanol (KLK Co., Korea). To measure the ECG signals, eight participants (Male:Female=1:1) were collected, and then, the signals were measured at rest-state and stress-state in anechoic chamber using Lead I method. From the measured ECG signals, heart rate (HR) and R-R intervals were acquired by using MP150 (Biopac system Inc., USA) and Acqknowledge (ver. 4.2, Biopac system Inc., USA), and then, analyzed by using Kubios HRV (ver. 2.0., Biosignal Analysis and Medical Imaging Group, Finland). To examine the morphology of the signals, direct visual evaluation was performed. Also, to statistically compare to the signals, Wilcoxon signed-rank test was conducted by using R statistical language and RStudio (1.0.143 ver., RStudio, Inc., USA). As a result, the ECG waveforms measured by the two different types of electrodes looked similar, especially, QRS-complex, P-wave and T-wave as well as R-peaks properly appeared. Also, there was not a significant difference of HR and RR-intervals measured by the two different types of electrodes. It demonstrated that the new AgNW/PU nanoweb electrodes could perform properly as ECG electrodes.
TL;DR: In this paper, the performance and morphology of ramie fibers degummed using Fenton reagent was investigated, and the experimental results indicated that Fenton can serve as an effective oxidation degumming agent under weak acid condition.
Abstract: This paper investigated the performance and morphology of ramie fibers degummed using Fenton reagent. In order to deeply understand the reaction characteristics, SEM, XRD and FT-IR were employed to characterize the morphologies, chemical components and crystallinity of degummed fibers. Also, the physical and mechanical properties such as tenacity, breaking elongation, density, softness and degree of polymerization of degummed fibers were measured. The experimental results indicated that Fenton can serve as an effective oxidation degumming agent under weak acid condition. The new degumming method could remove more gummy components from raw ramie, whereas the cellulose content in treated fibers was further increased compared with the alkaline oxidation degumming. The fibers degummed using Fenton showed slight increase in tenacity and significant increase in density as well as breaking elongation comparing with alkaline oxidation degumming. The degummed fibers were also characterized in terms of SEM, XRD and FTIR which confirmed the effectiveness of the new degumming method.
TL;DR: In this article, a graphene/WPU composite solution and film was prepared to conduct basic research for developing electrical heating textiles which is not harmful to the human body, flexible and excellent in electrical properties.
Abstract: Graphene is classified as a carbon-based material. Structurally, graphene is made up of carbon-based two-dimensional atomic crystals and a one atom thick planar sheet of sp2-bonded carbon atoms. This sort of arrangement in graphene makes it a unique material with exceptional mechanical, physicochemical, thermal, electrical, optical, and biomedical properties. Methods for graphene-based fabric production mainly use graphene-based materials such as graphene (G), graphene oxide (GO), and reduced graphene oxide (rGO) coated on fabric or yarn. Waterborne polyurethane (WPU) is one of the most rapidly developing and active branches of polyurethane chemistry. More and more attention is being paid to graphene-coated fabrics owing to their low temperature flexibility, the presence of zero or very few VOCs (volatile organic compounds), water resistance, pH stability, superior solvent resistance, excellent weathering resistance, and desirable chemical and mechanical properties. It is used as a coating agent or adhesive for fibers, textiles, and leather. Also, graphene-containing materials have been used to enhance the properties of WPU. In this study, graphene/WPU composite solution and film was prepared to conduct basic research for developing electrical heating textiles which is not harmful to the human body, flexible and excellent in electrical properties. Graphene/WPU composite solutions were prepared with a graphene content of 0, 2, 4, 8, and 16 wt%, and graphene/WPU film was prepared with solution casting method. The graphene contents were analyzed for their surface morphology, electrical properties, and electrical heating properties.
TL;DR: In this paper, the thermal decomposition behavior of polyglycolic acids and poly glycolide is similar, regardless of end groups and synthetic routes which is supposed to be random chain cession.
Abstract: Polyglycolic acid (PGA) was successfully synthesized via solution and melt/solid polycondensations. PGA was synthesized by solution polymerization under vacuum by using diphenylsulfone as solvent and methanesulfonic acid as catalyst and the inherent viscosity of resultant PGA was 0.2 dl/g. The intrinsic viscosity was obtained up to 0.35 dl/g of the PGA synthesized by melt/solid polycondensation. Whereas, PGA synthesized by longer hours of SSP was insoluble in most of the known solvents, which might have higher molecular weight as well as crystallinity. Crystallographic structure of PGA was confirmed by XRD and the resulting PGA polymer was similar in thermal degradation to that of commercially available polyglycolide (Kuredux), synthesized by ring opening polymerization. Both PGAs were characterized for thermal decomposition kinetic studies using thermaogravimetric analysis (TGA), to investigate the effect of end-group and molecular weight on thermal degradation behavior. TGA was performed at 6 different heating rates from 5 to 50 °C/min and data was analyzed by three different approaches to obtain activation energy. Activation energy from Kissinger’s approach was 112 kJ/mol for lab synthesized PGA and 119 kJ/mol for Kuredux, whereas from Flynn and Wall’s method, it was observed as 115 kJ/mol and 121 kJ/mol for solution-polymerized PGA and Kuredux respectively and activation energies calculated from dynamic experiment method was also comparable of both PGAs. From dynamic experiment method linearity curve starts as low as 1 % decomposition and continues as high as 97 % with decomposition temperature ranges 219 to 380 °C for PGA and 230 to 406 °C for Kuredux. Consequently, Kissinger’s method, Flynn and Walls method and the dynamic experiment method reveal that the thermal decomposition behavior of polyglycolic acids and polyglycolide is similar, regardless of end groups and synthetic routes which is supposed to be random chain cession.
TL;DR: In this paper, the results revealed the prominent role of dyeing pH in determining the dyeing mechanism and dye adsorption isotherm type and showed that the affinity, dyeing rate steadily increased with temperature.
Abstract: The dual-mode adsorption model was used to investigate the adsorption behavior of cochineal natural dye on wool fibers. Kinetic, thermodynamic, and equilibrium characteristics were investigated in terms of the adsorption isotherm, affinity, enthalpy and entropy changes, dyeing rate, diffusion coefficient, and activation energy of dye diffusion. The results revealed the prominent role of dyeing pH in determination of dyeing mechanism and dye adsorption isotherm type. At pH 4, dual Langmuir-Nernst model with the highest correlation coefficient was found as the most appropriate isotherm model to describe the adsorption behavior of cochineal onto wool fibers while at pH 6, the adsorption isotherm was the Nernst type. Cochineal adsorption onto wool was exothermic which resulted in progressive fall in affinity and equilibrium dye up-take values with increasing temperature. Moreover, dyeing rate steadily increased with temperature. At pH 4, affinity, dyeing rate, and diffusion coefficient demonstrated higher values compared to pH 6 whereas enthalpy and entropy changes, and activation energy showed lower values. Additionally, negative value for activation energy was obtained at pH 6. The results are deliberated based on the different possible interactions between cochineal dye and wool fiber.
TL;DR: In this article, a ternary composite consisting of carboxymethyl chitosan, hemicellulose, and nanosized TiO2 (CHNT) was used for heavy metal contaminated water treatment.
Abstract: A ternary composite consisting of carboxymethyl chitosan, hemicellulose, and nanosized TiO2 (CHNT) was prepared by incorporating TiO2 nanoparticles into the pre-synthesized carboxymethyl chitosan-hemicellulose polysaccharide network. The microstructure and chemical composition of the obtained CHNT was characterized by TEM, SEM, FTIR, and TGA. The adsorption of some toxic heavy metals including Ni(II), Cd(II), Cu(II), Hg(II), Mn(VII), and Cr(VI), onto the as-prepared CHNT composite was investigated. The effects of pH, temperature and contacting time on the adsorption process were studied. Results revealed that the CHNT composite exhibited efficient adsorption capacity of the above metal ions from aqueous solution due to its favorable chelating groups in structure. The adsorption process was best described by the pseudo-second-order kinetic model, while isotherm modeling revealed that the Langmuir equation better described the adsorption on CHNT as compared to Freundlich model. Moreover, the CHNT loaded metal ions can be easily regenerated with EDTA and reused repeatedly up to five cycles. The environmental friendly hybrids were expected to be a promising candidate for future practical application in heavy metal contaminated water treatment.
TL;DR: In this article, polyimide (P84) nanofibers of 200-500 nm were deposited uniformly on needle punched aramid felt with basis weight of 260-350 g/m2 by optimized electrospinning.
Abstract: Polyimide (P84) nanofibers of 200-500 nm were deposited uniformly on needle punched aramid felt with basis weight of 260-350 g/m2 by optimized electrospinning. High temperature adhesive was then electro-sprayed on the nanofiber side deliberately to bind a thin protective layer made of temperature-resistant non-wovens. The three layer structure was afterwards enforced by hot pressing to form composite filter media. The application of the adhesive was tailored not to affect the permeability of the substrate felt while exerting adhesion strength of over 1000 kPa for the media to be suitable for flue gas dust treatment under 240 oC. When 0.3-10 μm NaCl aerosols were used as the simulated dusts, it was found that even a small amount of P84 nanofibers could obviously elevate the filtration efficiency. The composite showed 100 % removal efficiency of particles equal and greater than 2.0 μm, and 99.5 % for particles 1.0-2.0 μm in diameter.
TL;DR: In this paper, the electrospinnability of aloe vera gel and the release mechanism as well as the kinetic of its release from poly vinyl alcohol (PVA) nanofibrous matrix is reported.
Abstract: The electrospinnability of aloe vera gel and the release mechanism as well as the kinetic of its release from poly vinyl alcohol (PVA) nanofibrous matrix is reported. Addition of PVA by an amount of only 1 % (w/w) to aloe vera solution made its electrospinning possible leading, to the fabrication of aloe vera nanofiber (99 %) with an average diameter of around 80 nm. Electrospinning of aloe vera-PVA solutions (25-75, 50-50, 75-25) led to the fabrication of nanofibers with average diameter of around 55, 105 and 110 nm, respectively. FTIR analysis showed no reaction between aloe vera and PVA. X-ray diffraction patterns showed no considerable effect from aloe vera on the amorphous structure of PVA. The release mechanism of aloe vera from PVA matrix in phosphate buffer solution was of Ficki type and the kinetic of the release followed Higuchi model. Aloe vera or aloe vera-PVA electrospun nanofibers may be used as an aloe vera release system in wound care. In a phosphate buffer solution, at least 60 percent of aloe vera is released in the first hour and about 90 % of aloe vera is released in 2-4 hours depending on the diameter of the nanofibers.