Monofilament Composites Research Articles

Characterization and mechanism analysis of interfacial shear strength between individual aramid fiber and epoxy by oxygen plasma treatment at elevated temperatures: Experiment and simulation

The weak adhesion between aramid fibers Ⅲ and the resin matrix, due to its smooth surface and high inertness of the fibers. This property restricts the mechanical properties of the composites in high temperatures environments. This work describes the treatment of aramid fibers Ⅲ with oxygen plasma to introduce reactive oxygen-containing functional groups onto fiber surface. The analysis focused on the impact of interfacial friction and interfacial wettability on the transfer of load across composites at various temperatures. According to the X-ray photoelectron spectroscopy (XPS) analysis, the fiber surface showed an increase in the number of active groups after plasma treatment. In addition, two new oxygen-containing functional groups -C-O- and -O-CO appeared. The use of Scanning Electron Microscopy (SEM) and atomic Force Microscopy (AFM) showed that the plasma treatment has an etching effect on the fiber surface and increases the roughness of the fiber surface. Furthermore, after plasma treatment, the fibers adhered to the resin matrix through hydrogen bonding and π-π bonding. The utilization of this technique led to a significant enhancement in the interfacial properties of monofilament composites across various temperature ranges. The IFSS of plasma-treated aramid fiber Ⅲ/EP exhibited increases of 38 % at the test temperature of 25℃. Surprisingly, the IFSS of plasma-treated aramid fiber III/EP exhibited a significant increase of 52 % at the test temperature of 120℃. In this paper, COMSOL software was utilized to simulate the IFSS before and after plasma treatment at different temperatures. Mechanistically explains the effect of temperature on the interfacial mechanical properties of composites.

Simultaneously enhancing microelastic response and degradability for poly(butylene succinate) composite monofilaments by silanized microcrystalline cellulose

Simultaneously enhancing microelastic response and degradability for poly(butylene succinate) composite monofilaments by silanized microcrystalline cellulose

The effect of interfacial properties of PBO fiber surface modified by oxygen plasma on quasi-static and dynamic mechanical properties of monofilament composites

PBO(p-phenylene benzobisoxazole) fibers have great application potentials in various engineering fields while the excessively smooth surface hinders their property to a large extent. In present work, the surface of PBO fiber was modified by oxygen plasma treatment with different power and time, and the epoxy resin composite before and after PBO fiber modification was prepared. The results show that the O/C ratio increases with the introduction of carboxyl group on the surface of PBO fiber. With the increase of plasma treatment power and time, the surface roughness of the fiber surface increases first and then decreases. When the treatment time of 5 minutes under 150 W, the IFSS increases from 21.01 MPa to 56.60 MPa, reaching the optimum property. After modification, the maximum strength of monofilament fiber decreases slightly under quasi-static and dynamic conditions. The results in present work can provide reference for the subsequent structural design of overall composite materials.

Enhanced mechanical properties of poly(butylene succinate)/silk sericin composite monofilaments with silane coupling agent KH570

Biodegradable Poly (butylene succinate) (PBS) composites with natural polymers have been widely developed, the compatibility of PBS and natural polymers is often the first consideration in terms of performance. In this work, PBS/silk sericin composite monofilaments (content of silk sericin is 6 wt%) with γ-methacryloxypropyltrimethoxysilane (KH570) as the coupling agent were fabricated by reactive melt-mixing, spinning, and stretching. The effect of KH570 content (1–3 wt%) on the morphology, mechanical property and biodegradation was studied. The reaction between the hydroxyl groups of silk sericin and -Si-OH of KH570 was analyzed by Fourier transform infrared spectroscopy. The cross-section morphology of the monofilaments obtained from SEM and EDS images indicates that the dispersion of silk sericin is improved with the increase of KH570 content. Compared with unmodified composite monofilaments, the composite monofilament with 2 wt% KH 570 shows the best mechanical performance (102% and 80% improvement in tensile strength and elongation at break respectively). The incorporation of silk sericin, which possesses skin-friendly properties, imparts composite monofilaments with advantages in the fields of clothing, headgear, shoe uppers and other related applications. Otherwise, the silk sericin can enhance the biodegradability velocity of PBS/silk sericin composite monofilaments. And the weight loss of the composite monofilaments buried in soil can be adjusted by the synergistic effect of silk sericin and KH570.

Solvent-free extrusion of a LiFePO4-based monofilament for three-dimensional printing of a lithium-ion battery positive electrode

To meet the final objective of 3D printing a high-performance liquid-electrolyte lithium-ion battery using Fused Filament Fabrication (FFF), a positive electrode filament formulation based on LiFePO4 and carbon nanofibers (CNF) is, herein, in-depth investigated. A highly-loaded composite monofilament containing a co-continuous structure of an immiscible non-polar (polypropylene-PP) and polar (polycaprolactone-PCL) thermoplastic polymers blend is successfully produced by hot-melt extrusion. This specific formulation confers desirable properties to the 3D printed electrode such as a mechanical integrity during cycling and good affinity with the electrolyte. Furthermore, for up-scale purpose, the incorporation of an optimal amount of thermoplastic elastomers (TPE) into the filament composite to gain in flexibility is examined and its ability to be rolled around a spool at the extruder exit is modelled on the basis of experimental values of mechanical properties. In addition, it is shown that the larger-scale extruded filament has better electronic properties and the corresponding 3D-printed electrode exhibits excellent electrochemical behavior, making it possible to envisage an industrial scale-up production.

Piezoresistive Response of Carbon Nanotube Yarn Monofilament Composites under Axial Compression

The hierarchical structure and microscale dimensions of carbon nanotube yarns (CNTYs) make them great candidates for the development of integrated sensing applications. The change in the electrical resistance of CNTYs due to mechanical strain, known as piezoresistivity, is the principal mechanism in strain sensing using CNTYs. While the axial tensile properties of CNTYs have been studied widely, studies on the axial piezoresistive response of CNTYS under compression have been limited due to the complexities associated with the nature of the experiments involving subjecting a slender fiber to compression loading in its axial direction. In this study, the piezoresistive response of a single CNTY embedded into a polymeric resin (CNTY monofilament composite) was investigated under axial compression. The results suggest that the CNTY exhibits a strong piezoresistive response in the axial direction with sensitivity or gauge factor values in the order of 0.4–0.5 for CNTY monofilament composites. The piezoresistive response of the CNTY monofilament composites under compression was compared to that under tension and it was observed that the sensitivity appears to be slightly lower under compression. The potential change in sensitivity between the freestanding CNTY and the CNTY monofilament composite under compression is still unknown. Knowing the axial piezoresistive response of the CNTYs under both tension and compression will enable their use in sensing applications where the yarn undergoes compression including those in aerospace and marine structures, and civil or energy infrastructure.

Study and Modeling of Polypropylene Composite Monofilament Warm-Up in the Process of Thermal Treatment

Study and Modeling of Polypropylene Composite Monofilament Warm-Up in the Process of Thermal Treatment

Experimental Study on the Critical Current Properties of Flexible Nb3Al Superconducting Wires in Cryocooler System

In recent years, Jelly-rolled Nb/Al composite monofilament Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Al superconducting wires with an outer diameter of 30 μm, and multi-stranded Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Al wires were successfully fabricated by NIMS in Japan. So, it is necessary to measure the temperature dependence of the critical current of Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Al wires in cryocooler system for development of superconducting applications cooled by conduction cooling method. The single and multi-stranded ultrafine Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Al superconducting sample wires with different outer diameter were prepared to evaluate the critical current properties. The critical currents of sample wires were evaluated by the current sweep method and constant current method. In this study, the sample wires were soldered to the copper wire to prevent burnout of the sample wire during critical current measurements. Therefore, the amount of current shunted to the copper wire was estimated to accurately evaluate the critical current of the superconducting wire. Also, the critical current of Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Al wires due to bending strain (bending radius of 5 to 15 mm) was experimentally investigated. From the critical current measurement results of Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Al wires with different cross-sectional structures, it was confirmed that the superconducting properties of the wires were improved by reducing the wire diameter. It was shown that the critical current density of the developed Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Al wire is lower than that of REBCO wire, but higher than that of commercial NbTi and Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Sn wires.

Electrically Conducting Polymer Composite Monofilaments with a Blended Filler

Electrically Conducting Polymer Composite Monofilaments with a Blended Filler

Poly(butylene succinate)/cellulose composite monofilaments with microelastic response based on interfacial bonding

Biodegradable fibers have been widely developed for advanced textile fields, but their practical applications are limited by large plastic deformation. To solve this problem, we developed a solvent-free melt spinning method to prepare poly(butylene succinate)/microcrystalline cellulose (PBS/MCC) composite monofilaments. The high modulus and rigidity of MCC limit PBS plastic deformation and the in-situ formed hydrogen bonds between MCC and amorphous PBS improved MCC dispersion and led to the formation of rigid MCC physical crosslink points. The composite monofilaments with 10–25 wt% of MCC after multi-stage and high-ratio hot stretching showed a double yielding behavior and microelastic response, indicating the permanent deformation resistance of the composite monofilaments under small deformation. Moreover, the addition of MCC improved the biodegradability of the composite monofilaments after 60 days buried in soil. Therefore, our study provides a design strategy of microelastic composite monofilaments for maintaining dimensional stability during use and accelerating degradation during waste.

Preparation of graphene-modified PLA/PBAT composite monofilaments and its degradation behavior

The graphene-modified composite poly(lactic acid) (PLA)/poly(butylene adipate-co-terephthalate) (PBAT) monofilaments were prepared by melt spinning. The effects of graphene (GR) contents on the microstructural, thermal, dynamic mechanical, and mechanical properties and the degradation behavior of the graphene-modified composite PLA/PBAT monofilaments were studied. Scanning electron microscopy (SEM) confirmed the improved compatibility of the PLA particles in the PBAT matrix, while the transmission electron microscopy (TEM) demonstrated the size and morphology of the GR distribution in the polymer. As the GR content increased, dynamic mechanical analysis (DMA) clarified a decrease of the difference of glass transition temperature (Tg) between PLA and PBAT. In addition, the mechanical properties of the composite monofilaments were significantly enhanced at a GR content of 0.2 wt%. Weight loss rate of the composite monofilaments under soil and sea degradation conditions were obviously related to the GR content.

Effect of Curing Temperature of Epoxy Matrix on the Electrical Response of Carbon Nanotube Yarn Monofilament Composites

In order to evaluate the capability of carbon nanotube yarn (CNTY)-based composites for self-sensing of temperature, the temperature-dependent electrical resistance of CNTY monofilament composites was investigated using two epoxy resins: one that cures at 130 °C (CNTY/ERHT) and one that cures at room temperature (CNTY/ERRT). The effect of the curing kinetics of these epoxy resins on the electrical response of the embedded CNTY was investigated in prior studies. It was observed that the viscosity and curing kinetics affect the level of wetting and resin infiltration, which govern the electrical response of the embedded CNTY. In this work, the cyclic thermoresistive characterization of CNTY monofilament composites was conducted under heating–cooling, incremental heating–cooling, and incremental dwell cycles in order to study the effect of the curing temperature of the epoxy matrix on the electrical response of the CNTY monofilament composites. Both monofilament composites showed nearly linear and negative temperature coefficients of resistance (TCR) of −7.07 × 10−4 °C−1 for specimens cured at a high temperature and −5.93 × 10−4 °C−1 for specimens cured at room temperature. The hysteresis loops upon heating–cooling cycles were slightly smaller for high-temperature cured specimens in comparison to those cured at room temperature. A combination of factors, such as resin infiltration, curing mechanisms, intrinsic thermoresistivity of CNTY, variations in tunneling and contact resistance between the nanotubes and CNT bundles, and the polymer structure, are paramount factors in the thermoresistive sensitivity of the CNTY monofilament composites.

The effects of design parameters on the elastic properties of PLA-Graphite composites fabricated by 3D printing

Abstract. Recently, in 3D printing, consumables such as polymers, metals, and ceramics are being replaced with composites, which makes it possible to enhance the mechanical and other important properties of products.&#x0D; The purpose of this study is to investigate the effects that the orientation and thickness of the layers of printed samples made of composite monofilament based on PLA+ with a 5% content of layered graphite, and other such parameters, have on the elastic properties of the printed samples. The samples, developed in accordance with the DSTU EN ISO 527-2: 2018 standard, were printed using the FDM technology with three different orientation angles (0o, 45o, 90o) and three layer thicknesses (0,1 mm, 0,2 mm, 0,3 mm) for each angle. Tensile tests were performed using the complete factorial experiment design (consisting of two factors at three levels, with nine tests in total). Based on the results of these tests, a regression model was developed to describe the relationship between the (effective) modulus of elasticity and the selected design parameters.&#x0D;

Monitoring of Curing and Cyclic Thermoresistive Response Using Monofilament Carbon Nanotube Yarn Silicone Composites

The curing process and thermoresistive response of a single carbon nanotube yarn (CNTY) embedded in a room temperature vulcanizing (RTV) silicone forming a CNTY monofilament composite were investigated toward potential applications in integrated curing monitoring and temperature sensing. Two RTV silicones of different crosslinking mechanisms, SR1 and SR2 (tin- and platinum-cured, respectively), were used to investigate their curing kinetics using the electrical response of the CNTY. It is shown that the relative electrical resistance change of CNTY/SR1 and CNTY/SR2 monofilament composites increased by 3.8% and 3.3%, respectively, after completion of the curing process. The thermoresistive characterization of the CNTY monofilament composites was conducted during heating–cooling ramps ranging from room temperature (RT~25 °C) to 100 °C. The thermoresistive response was nearly linear with a negative temperature coefficient of resistance (TCR) at heating and cooling sections for both CNTY/SR1 and CNTY/SR2 monofilament composites. The average TCR value was −8.36 × 10−4 °C−1 for CNTY/SR1 and −7.26 × 10−4 °C−1 for CNTY/SR2. Both monofilament composites showed a negligible negative residual relative electrical resistance change with average values of ~−0.11% for CNTY/SR1 and ~−0.16% for CNTY/SR2 after each cycle. The hysteresis amounted to ~21.85% in CNTY/SR1 and ~29.80% in CNTY/SR2 after each cycle. In addition, the effect of heating rate on the thermoresistive sensitivity of CNTY monofilament composites was investigated and it was shown that it reduces as the heating rate increases.

Interfacial adhesion quality in 3D printed continuous CF/PA6 composites at filament/matrix and interlaminar scales

Fused deposition modelling (FDM) is a promising additive manufacturing technology for the fabrication of continuous fibre reinforced thermoplastic composites. However, a major concern is the performance of the interfacial bonding in these composites. The aim of this study is to evaluate the interface quality of a 3D printed carbon/PA6 composite at two scales: the filament/matrix scale and the interlaminar one. Two different types of samples were made: monofilament composites for performing fragmentation tests, and double cantilever beam (DCB) samples for realising mode I interlaminar fracture tests. After measuring the strength of the individual carbon filament, the fragment lengths were observed by micro-CT and measured in monofilament composites in order to calculate the interfacial shear strength (IFSS). The DCB tests allowed the determination of the interlaminar fracture toughness (GIc) for 0°//0° and +45°//-45° interfaces. The obtained results are promising for such 3D printed composites.

Effect of Polymer Viscosity and Polymerization Kinetics on the Electrical Response of Carbon Nanotube Yarn/Vinyl Ester Monofilament Composites.

The effect of polymerization kinetics and resin viscosity on the electrical response of a single carbon nanotube yarn (CNTY) embedded in a vinyl ester resin (VER) during polymerization was investigated. To analyze the effect of the polymerization kinetics, the concentration of initiator (methyl ethyl ketone peroxide) was varied at three levels, 0.6, 0.9, and 1.2 wt.%. Styrene monomer was added to VER, to reduce the polymer viscosity and to determine its effect on the electrical response of the CNTY upon resin wetting and infiltration. Upon wetting and wicking of the CNTY by VER, a transient decrease in the CNTY electrical resistance (ca. −8%) was observed for all initiator concentrations. For longer times, this initial decrease in electrical resistance may become a monotonic decrease (up to ca. −17%) or change its trend, depending on the initiator concentration. A higher concentration of initiator showed faster and more negative electrical resistance changes, which correlate with faster gel times and higher build-up of residual stresses. An increase in styrene monomer concentration (reduced viscosity) resulted in an upward shift of the electrical resistance to less negative values. Several mechanisms, including wetting, wicking, infiltration, electronic transfer, and shrinkage, are attributed to the complex electrical response of the CNTY upon resin wetting and infiltration.

Preparation and Characterization of Recycled PP/Organo-Clay Filter for Dyeing Ability

Organo-modified clay was used to prepare waste polypropylene/clay composite by melt mixing method. Composites were then melt spun into linear filaments. Attention is given to how the organoclay influence the morphology and the dyeability of resultant waste PP filaments. Scanning electron microscopy was used to investigate the surface morphology and cross section of the filaments. Dyeing studies underlined the improvement of dye affinity of elaborated filaments to acid, basic, and disperse dyes. Moreover, we observed that waste PP and its composite monofilaments have the highest dyeability when using disperse dye. The prepared filaments were then used to fulfill a filter for the treatment of textile dye waste water. Thus, 3D geometrical design of the filter structure was realized by the SolidWorks mechanical design software.

Development of Composite Fibrous Materials with Improved Mechanical Properties

Composite monofilaments based on a polyethyleneterephthalate matrix and inorganic dispersed nanoparticles (silicon dioxide and aluminum oxide) were produced by the melt method. The structure was investigated, and the optimum parameters of the formation process were determined. It was shown that composite materials with improved deformation–strength characteristics can be obtained if small concentrations of modified dispersed nanofillers are added.

Influence of Aluminum Oxide Nanoparticles on Formation of the Structure and Mechanical Properties of Microfibrillar Composites

The effect of nanosize alumina (Al2O3) concentration on the morphology and mechanical properties of microfibrillar composites obtained by processing the thermodynamically incompatible polypropylene/ copolyamide (PP/CPA) blend was studied. It was established that composite monofilaments exhibited a selfreinforcing effect due to the in situ formation of PP fibrils (microfibers) in the CPA matrix. The tensile strength and the initial elastic modulus of the filaments studied depended on their structure and correlated with dimensional characteristics of the disperse phase component. It is shown that the introduction of Al2O3 nanoparticles in an amount of (0.1-3.0) wt.% allows one to adjust the structure formation process of the dispersed phase component to obtain composites with a thin homogeneous morphology. The maximum performance was achieved for filaments formed from a composition containing 1.0 wt.% alumina. In this case, microfibers were the predominant type of structure, and their diameters were minimum. The increasing ability of the jets of nanofilled melts of PP/CPA blends to the longitudinal deformation was due to the formation of a more perfect microfibrillar structure during extrusion. This makes it possible to obtain filaments from such blends on already existing extrusion equipment.

Using mussel shell wastes as an additive for the production of thermally improved polypropylene composite monofilaments

In this study, powdered waste mussel shells were used as a filler to improve the thermal properties of polypropylene monofilaments. Composite polypropylene monofilaments including various amounts of mussel shell particles were produced by melt mixing and extrusion. Thermal characterization was performed with the thermogravimetric analysis and differential scanning calorimetry. In addition, tensile tests and limiting oxygen index tests were carried out to analyze the mechanical behavior and the flammability, respectively. X-ray diffraction were used to analyze crystal structure changes of the monofilaments. According to the test results, increased filler ratio has a limited effect to limiting oxygen index of monofilaments. In the X-ray diffractograms, the lowest intensity loss was observed for the monofilament with 5% filler due to a homogeneous dispersion of lower filler content in the structure. Furthermore, thermal stability and crystallization temperature of the monofilaments increased by increased filler ratio.