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In order to avoid environmental pollution by effluents, the incorporation of electrical conductive yarns in a waterproof membrane allows detecting a leak or crack on industrial concrete structure. The membrane is made of composite materials: a glass textile structure equipped with the detector yarns and molded in an epoxy resin. The liquid’s detection and the data’s transmission depend on the yarn’s conductivity variation and its chemical and physical properties. This study aims to develop a water detector monofilament from conductive polymer composites (CPC): an immiscible polymers blend (polyamide 6.6/elastomer) filled with carbon nanotubes (CNT). The addition of elastomer in the CPC yarn is important to withstand the mechanical deformation of the resin structure without breaking. The morphology of the immiscible polymers blend and the localization of the CNT influence the electrical conductivity of the yarn and thus, its property of water detection. Two principles of water detection are investigated with this blend: the short circuit and the absorption. For the short circuit, the presence of liquid is detected when the liquid creates a conductive path between two yarns in parallel. While, the absorption principle is based on the conductivity variation with the yarn’s swelling in contact with water.

Nowadays, the heating textiles are used in many fields of applications as medicine or comfort. The heating property for the most part of these textiles was ensured by electrical conductive fiber as metallic yarn thanks to Joule Effect. A challenge for heating textile is to have an electrical conductive fiber which has a temperature self-regulation at the comfort temperature. Thanks to this temperature self-regulation, the heating textile reaches more autonomy. To develop this kind of textile, conductive polymer composite (CPC), which is the combination between an insulating polymer and electrical conductivity nanofillers [1], is made by melt spinning. The temperature self-regulation is provided by the positive temperature coefficient (PTC) effect, which allows switching between an electrical conductivity state and an insulating state when the CPC is close to a transition phase temperature (glass transition temperature or melt temperature). However, when the PTC effect can take place at the melting point, the mechanical properties are not involved. So to maintain the final product an immiscible polymer blend was used: one polymer was the CPC and the second polymer was an insulating polymer with a higher melting point than the target temperature. In fact, the CPC involve the electrical conductivity and the PTC effect, whereas the insulating polymer involves the mechanical properties. However, a high electrical conductivity is necessary to reach the comfort temperature (defined around 42°) by Joule Effect. So to reach this temperature, the coating on a metallic yarn by the conductive immiscible polymer blend was used. The electrical conductivity of this product was improved by the metallic yarn and the self-regulating temperature by the PTC effect of the immiscible polymer blend (figure 1). In this paper the immiscible polymer blend used is a polycaprolactone (PCL) filled with multiwall carbon nanotubes (MWCNT) and a polypropylene (PP). In fact, in a previous paper the co-continuity and the selective localisation of the fillers in the PCL for this blend was studied [2]. The influence of the thickness CPC coating and the influence of the structure of metallic yarn were studied on the electrical conductivity, the Joule Effect and PTC effect.

The human body exchanges heat through the environment by various means, such as radiation, evaporation, conduction, and convection. Thermo-physiological comfort is associated with the effective heat transfer between the body and the atmosphere, maintaining the body temperature in a tolerable thermal range (36.5–37.5ºC). In order to ensure comfort, the body heat must be preserved or emitted, depending on external conditions. If the body heat is not properly managed, it can cause hyperthermia, heatstroke, and thermal discomfort. Conventionally, heating, ventilation, and air conditioning systems are used to provide comfort. However, they require a huge amount of energy, leading to an increase in global warming, and are limited to indoor applications. In recent decades, scientists across the world have been working to provide thermal comfort through wearable innovative textiles. This review article presents recent innovative strategies for moisture and/or thermal management at the material, filament/fiber, yarn, and fabric scales. It also summarizes the passive/active textile models for comfort. Integrating electrical devices in garments can rapidly control the skin temperature, and is dynamic and useful for a wide range of environmental conditions. However, their use can be limited in some situations due to their bulky design and batteries, which must be frequently recharged. Furthermore, adaptive textiles enable the wearer to maintain comfort in various temperatures and humidity without requiring batteries. Using these wearable textiles is convenient to provide thermal comfort at the individual level rather than controlling the entire building temperature.

An increasing interest is focused on the application of 3D printing for sensor manufacturing. Using 3D printing technology offers a new approach to the fabrication of sensors that are both geometrically and functionally complex. This work presents the analysis of the 3D-printed thermoplastic nanocomposites compress under the applied force. The response for the corresponding resistance changes versus applied load is obtained to evaluate the effectiveness of the printed layer as a pressure/force sensor. Multi-walled carbon nanotubes (MWNT) and high-structured carbon black (Ketjenblack) (KB) in the polylactic acid (PLA) matrix were extruded to develop 3D-printable filaments. The electrical and piezoresistive behaviors of the created 3D-printed layers were investigated. The percolation threshold of MWNT and KB 3D-printed layers are 1 wt.% and 4 wt.%, respectively. The PLA/1 wt.% MWNT 3D-printed layers with 1 mm thickness exhibit a negative pressure coefficient (NPC) characterized by a decrease of about one decade in resistance with increasing compressive loadings up to 18 N with a maximum strain up to about 16%. In the cyclic mode with a 1 N/min force rate, the PLA/1 wt.% MWNT 3D-printed layers showed good performance with the piezoresistive coefficient or gauge factor (G) of 7.6 obtained with the amplitude of the piezoresistive response (Ar) of about -0.8. KB composites could not show stable piezoresistive responses in a cyclic mode. However, under high force rate compression, the PLA/4 wt.% KB 3D-printed layers led to responses of large sensitivity (Ar = −0.90) and were exempt from noise with a high value of G = 47.6 in the first cycle, which is a highly efficient piezoresistive behavior.

An increasing interest is focused on the application of 3D printing for sensor manufacturing. Using 3D printing technology offers a new approach to the fabrication of sensors that are both geometrically and functionally complex. This work presents the analysis of the 3D-printed thermoplastic nanocomposites compress under the applied force. The response for the corresponding resistance changes versus applied load is obtained to evaluate the effectiveness of the printed layer as a pressure/force sensor. Multi-walled carbon nanotubes (MWNT) and high-structured carbon black (Ketjenblack) (KB) in the polylactic acid (PLA) matrix were extruded to develop 3D-printable filaments. The electrical and piezoresistive behaviors of the created 3D-printed layers were investigated. The percolation threshold of MWNT and KB 3D-printed layers are 1 wt.% and 4 wt.%, respectively. The PLA/1 wt.% MWNT 3D-printed layers with 1 mm thickness exhibit a negative pressure coefficient (NPC) characterized by a decrease of about one decade in resistance with increasing compressive loadings up to 18 N with a maximum strain up to about 16%. In the cyclic mode with a 1 N/min force rate, the PLA/1 wt.% MWNT 3D-printed layers showed good performance with the piezoresistive coefficient or gauge factor (G) of 7.6 obtained with the amplitude of the piezoresistive response (

The main objective of the present study was to investigate the increase in the electromagnetic shielding effectiveness (EMSE) of a set of five variants of three-dimensional (3D) warp interlock woven fabrics containing silver multifilament yarns arranged in a 3D orthogonal grid. The EMSE enlargement as a factor of increasing the quantity of the conductive material per unit area was investigated. The quantity of the conductive material per unit area in a 3D woven fabric can be enlarged by increasing either the yarn undulation or the number of conductive yarn systems, while the yarn density and yarn fineness are fixed. Thus, the binding depth of the conductive warp was gradually increased for the first four variants in order to increase the yarn undulation. Alternatively, the conductive weft system was doubled for the last variant with the aim of increasing the quantity of the conductive component. It should be noted that changing the weave structure requires less effort and energy while keeping the same threading of warps in the reed compared to altering the warp density. The EMSE was measured in an anechoic chamber and the shielding was satisfactory for all the variants in the frequency range of 1–6 GHz (19–44 dB). The results revealed that increasing only 7% of the waviness degree of the conductive warps led to 17% EMSE improvement due to increasing of the conductive yarns through the thickness of the variants. Moreover, no upward EMSE was detected for the last variant, despite the fact that the conductive weft system was doubled.

Purpose This paper aims to evaluate and simulate the impact of the build platform temperature of the three-dimensional (3D) printer, the structure and heat transfer of textiles on the adhesion and durability after washing properties of 3D printed polymer onto textile materials using thin layers of conductive and non-conductive extruded poly lactic acid monofilaments (PLA) deposited on polyethylene terephthalate (PET) woven fabrics through fused deposition modeling (FDM) process. Design/methodology/approach Prior to FDM process, thermal conductivity, surface roughness and mean pore size of PET woven fabrics were assessed using the “hot disk,” the profilometer and the capillary flow porometry methods, respectively. After the FDM process, the adhesion and durability after the washing process properties of the materials were determined and optimized based on reliable statistical models connecting those properties to the textile substrate properties such as surface roughness, mean pore size and thermal conductivity. Findings The main findings point out that higher roughness coefficient and mean pore size and lower thermal conductivity of polyester woven textile materials improve the adhesion properties and the build platform presents a quadratic effect. Additionally, the adhesion strength decreases by half after the washing process and rougher and more porous textile structures demonstrate better durability. These results are explained by the surface topography of textile materials that define the anchorage areas between the printed layer and the textiles. Originality/value This study is for great importance in the development of smart textiles using FDM process as it presents unique and reliable models used to optimize adhesion resistance of 3D printed PLA primary layer onto PET textiles.

In this study, a series of immiscible polymer blend fibers with polypropylene (PP) and polyvinyl alcohol (PVA) was obtained by a melt spinning process, and two different draw ratios were attempted. Efforts were made to obtain the porous PP fibers by removing the water-soluble PVA phase. The thermal properties of the blends were tested by thermogravimetric analysis and differential scanning calorimetry. The blends showed excellent thermal stability and differentiated fractionated crystallization behaviors of PP. The melt flow indexes of the blends were evaluated, exhibiting a higher fluidity than that of the neat polymers. Among the possible candidates for the spinning process, only the PP70–PVA30 had suitable spinnability, for which the draw ratio reached 3. The morphology of the fibers was investigated by selective extraction experiment and scanning electron microscopy, as well as wide-angle X-ray diffraction. The biphasic morphology and the crystallization behaviors varied according to the PVA content. Furthermore, the mechanical properties of the multifilament fibers were studied via tensile testing and dynamical mechanical analysis. The 70/30 weight ratio (PP/PVA) was the most suitable for producing biphasic fibers with a high degree of accessibility in PVA and mechanical properties that increase with the increase in the drawing ratio. The feasibility of fabric knitting was checked, and the mechanical properties and air permeability of the obtained textile structure were also evaluated.

This study focuses on the adoption of hybrid Janus kaolinite particles into immiscible PP–PVA blends for melt spinning, as an extension for the textile field. The anisotropic grafting of kaolinite ...

This work presents the effect of a melt-spinning process on the degradation behavior of bioresorbable and immiscible poly(d,l-lactide) (PLA) and polycaprolactone (PCL) polymer blends. A large range of these blends, from PLA90PCL10 (90 wt% PLA and 10 wt% PCL) to PLA60PCL40 in increments of 10%, was processed via extrusion (diameter monofilament: &empty, &asymp, 1 mm) and melt spinning (80 filaments: 50 to 70 &micro, m each) to evaluate the impact of the PCL ratio and then melt spinning on the hydrolytic degradation of PLA, which allowed for highlighting the potential of a textile-based scaffold in bioresorbable implants. The morphologies of the structures were investigated via extracting PCL with acetic acid and scanning electron microscopy observations. Then, they were immersed in a Dulbecco&rsquo, s Modified Eagle Medium (DMEM) media at 50 &deg, C for 35 days and their properties were tested in order to evaluate the relation between the morphology and the evolution of the crystallinity degree and the mechanical and physical properties. As expected, the incorporation of PCL into the PLA matrix slowed down the hydrolytic degradation. It was shown that the degradation became heterogeneous with a small ratio of PCL. Finally, melt spinning had an impact on the morphology, and consequently, on the other properties over time.

Antimicrobial textile structures are developed based on polypropylene (PP) and a natural material, hydrolyzed casein. The casein, from bovine milk, is subjected to acid hydrolysis in aqueous media, then blended into the PP matrix in the melt phase by extrusion. The obtained blend, containing 5 wt.% of hydrolyzed casein, is then processed by a melt spinning process to get multifilaments, leading to the production knitting structures. Thanks to the addition of the hydrolyzed casein, the obtained textile showed a strong antibacterial activity towards both Gram (+) and Gram (&minus, ) bacterial strains. The addition of 5 wt.% hydrolyzed casein does not significantly impact the mechanical properties of PP in the dumbbells form, but a small decrease was observed in the tenacity of the filaments. No moisture retention was observed after the addition of hydrolyzed casein, but the rheological behavior was slightly affected. The obtained results can contribute to addressing concerns regarding nonrenewable antibacterial agents used in textile materials, particularly their effects on the environment and human health, by offering antibacterial agents from a biobased and edible substance with high efficiency. They are also promising to respond to issues of wasting dairy products and recycling them, in addition to the advantages of using melt processes.

Enzyme immobilization is necessary process to improve the bioactivity and stability of the biocatalyst. In this study, glucose oxidase (GOx) enzyme was immobilized on plasma-treated fibrous carbon felt as a textile carrier to produce a heterogeneous catalyst. Genipin, as a naturally occurring crosslinker, that has less cytotoxicity than conventional crosslinkers, was used in the enzyme immobilization process. UV-Vis and FTIR spectra confirmed the crosslinking reaction between genipin and the primary amines of GOx enzyme, by forming blue-pigmented aggregates. GOx relative activity after crosslinking and immobilization on the carbon felt was maintained up to 40%, with stability in performance up to 6 cycles for the plasma treated carbon, while maintaining their bio-electro-activity as shown from cyclic voltammetry scans (CV). The obtained heterogeneous catalysts have been tested for use in sustainable wastewater treatment of Remazol Blue RR (RB) dyestuff by means of Bio-Fenton (BF) and enzymatic Bio-electro-Fenton (BEF) processes. The produced samples resulted in high color removal efficiency, up to 93% discoloration of (RB) for the first use in (BF) process in 3 h. Meanwhile, enzymatic (BEF) process resulted in up to 34% of COD removal, with simultaneous power density generation up to 0.16 ± 0.01 μW.cm−2 at a current density of around 10 ± 2 μA.cm−2 in 12 h. These results highlight the importance of genipin as a bio-based crosslinker for enzymes, and the potential use in both (BF) and (BEF) as sustainable approaches for wastewater treatment and as a step towards zero-energy degradation of organic matter.

Biobased lignin represents one of the possible materials for next-generation flame retardant additives due to its sustainability, environmental benefits and comparable efficiency to other flame retardant (FR) additives. In this context, this study presents the development of FR polyamide 11 (PA11) multifilament yarns and fabric structures containing different industrial lignins (i.e., lignosulfonate lignin (LL), and Kraft lignin (KL)) and zinc phosphinate (ZnP). The combination of ZnP and lignin (KL or LL) at different weight ratios were used to prepare flame retarded PA11 blends by melt mixing using a twin-screw extruder. These blends were transformed into continuous multifilament yarns by the melt-spinning process even at a high concentration of additives as 20 wt%. The mechanical test results showed that the combination of KL and ZnP achieved higher strength and filaments showed regularity in structure as compared to the LL and ZnP filaments. Thermogravimetric (TG) analysis showed the incorporation of lignin induces the initial decomposition (T5%) at a lower temperature, at the same time, maximum decomposition (Tmax) shifts to a higher temperature region and a higher amount of char residue is reported at the end of the test. Further, the TGA-FTIR study revealed that the ternary blends (i.e., the combination of LL or KL, ZnP, and PA11) released mainly the phosphinate compound, hydrocarbon species, and a small amount of phosphinic acid during the initial decomposition stage (T5%), while hydrocarbons, carbonyls, and phenolic compounds along with CO2 are released during main decomposition stage (Tmax). The analysis of decomposition products suggests the stronger bonds formation in the condensed phase and the obtainment of a stable char layer. Cone calorimetry exploited to study the fire behavior on sheet samples (polymer bulk) showed an improvement in flame retardant properties with increasing lignin content in blends and most enhanced results were found when 10 wt% of LL and ZnP were combined such as a reduction in heat release rate (HRR) up to 64% and total heat release (THR) up to 22%. Besides, tests carried out on knitted fabric structure showed less influence on HRR and THR but the noticeable effect on postponing the time to ignition (TTI) and reduction in the maximum average rate of heat emission (MARHE) value during combustion.

International audience; As microplastic studies grow, environmental concerns of all kinds of fibers are currently investigated. However, there is a gap in data regarding the impacts of digestion protocols on fibers integrity. This work focuses on the impact of five commonly used digestion protocols on the seven most produced fibers in traditional textile: three synthetics (polyamide 6.6 (PA 6.6), polyethylene terephthalate (PET) and polyacrylonitrile (acrylic)), one artificial (viscose), two vegetal natural (cotton and flax) and one animal natural (wool). The protocols to be tested were selected based on the literature: 10% KOH at 40 °C for 24 h; 10% KOH at 60 °C for 24 h; diluted NaClO at room temperature (~20 °C) for 15 h; 30% H2O2 at 40 °C for 48 h; Fenton's reagent with 30% H2O2 for 2 h at room temperature (~20 °C). The fibers were characterized before and after digestion. The effects of those protocols on fibers integrity have been assessed using several of their performance parameters. High degradations were observed for PET with 10% KOH 60 °C whereas almost no impact was observed at 40 °C. H2O2 digestion affects mechanical properties of different fibers, particularly PA 6.6. Both protocols should be avoided for synthetic fibers analyses. NaClO digestion mainly affected flax and viscose. Diluted NaClO at room temperature for 15 h, 10% KOH at 40 °C for 24 h and Fenton's reagent are more appropriate to maintain fibers integrity.

Nowadays, the market is flooded by smart textiles due to the major advances made in the development of flexible materials. Electrical conductivity is one of the most important properties, which can be assured by the introduction of metallic filaments in the yarns. However, such introductions of metallic filaments can cause a decrease of the characteristics of textile (flexibility, durability). Thus, a lot of studies focus on the development of electrical conductivity that does not decrease the characteristics of textile. An alternative to develop conductive polymer composites (CPC), is conductive fillers which can be integrated into the polymer. The current technic a bulk functionalization of the polymer during melt spinning allowing a thermoplastic yarn to become electrically conductive. In this study, the electrical conductivity of carbon black (CB) fillers filled multifilaments based on polyamide 12 (PA12) was optimized. The CPC were prepared in two steps: the first step was the incorporation of the fillers in PA12 by twin screw extrusion, and the second step was the melt spinning to obtain multifilament yarns. After extrusion, the blend has an electrical conductivity of 101 S/m. However, after the melt spinning of this blend, the electrical conductivity dropped sharply to 10-6 S/m. Several experimental parameters during the melt spinning can modify the structure filaments and impact on their electrical conductivity, which could explain this loss of electrical conductivity. Drawing out of rod during extrusion, as well as different melt spinning parameters, such as volumetric pump output and speed variation of the drawing rolls, were identified as key factors that not only influence the electrical conductivity but also the mechanical properties of the yarn. A low drawing ratio combined with a low pump output can increase the electrical conductivity. With the same value of volumetric pump output and the same supply roll speed, if the drawing roll speed increases from 225 rpm (rpm) to 450 rpm, the electrical conductivity decreases by a factor of 10, respectively 7.10-5 S/m and 7.10-6 S/m. Observations by transmission electron microscopy (TEM) of the two CBs inside PA12 give insight the dispersion of nanofillers, which effects on the CB physical network and its subsequent electrical conductivity. At the scale of the yarn, twisting can increase the contact path between the monofilaments and increase (from 10-6 S/m to 10-5 S/m) the global conductivity until a plateau for the multifilament. Thus, the key factors explaining this loss of electrical conductivity between the rod and the multifilament were identified. However, these parameters also effect the mechanical characteristic of the materials too.

This study investigates the thermal decomposition and fire behavior of zinc phosphinate (ZnP) in combination with low sulphonate content alkali lignin (LS) in a polyamide 11 (PA11) matrix. The influence of ZnP with LS on PA11 was assessed by using thermogravimetric analysis coupled with FTIR spectroscopy (TG-FTIR). Such decomposition products as hydrocarbons, amide and carbonyl units, phenolic and phosphinate compounds control the decomposition. The chemical structure of the condensed phase was evaluated by FTIR measurements carried out on the residues. The fire behavior was investigated using UL 94 vertical flame spread tests and cone calorimetry tests. In the ternary blends, the addition of LS promotes char formation as assessed by TG analyses; furthermore, ZnP contributes to flame inhibition mainly by radical trapping and partially by dilution of fuel, due to phosphinate ions and a small amount of phosphinic acid released in the gas phase. Besides, phosphate compounds are formed in the condensed phase. The combination of LS and ZnP enhanced flame-retardant properties due to the formation of a stable char layer with barrier features.

The aim of this study is to investigate the influence of hybrid textile woven fabric structure on the electrical resistivity. Weave structure was varied by varying the weave pattern and the conductive yarn density in the woven fabrics. Electrical surface and volume resistivity were measured and compared to the fabric structural properties. Results showed that not only the conductive yarns percentage has an important effect on the electrical resistivity but also the weave structure. The most influencing structural parameter on surface resistivity was the woven fabric surface profile as it controls the contact quality between the conductive yarns and the measuring electrodes. A high surface resistivity was noticed when the contact quality was poor. When this contact quality was good, a linear correlation was found between surface electrical resistivity and the cover firmness factor, the apparent conductive fiber surface area as well as the conductive yarn floating length of the woven structures.

In this paper, an overview of the bio-Fenton and bio-electro-Fenton processes for sustainable wastewater treatment is provided. These two methods have been used in recent years to treat many kinds of persistent pollutants while maintaining the sustainability in materials and power consumption compared to conventional methods, through efficient eco-designed systems. The different kinds of electrodes used for the bio-electro-Fenton are reviewed, along with the influencing factors affecting the efficiency of these methods, and the different designs used to construct the reactors. Moreover, the various organic pollutants from industrial sources, like effluents from textile and pesticides facilities, treated using these processes are also reported. However, the main challenge facing these technologies is to improve their performance, stability and lifetime to achieve more sustainable and cost-effective wastewater treatment on pilot and large scales. Hence, future perspectives and trends are discussed to overcome the drawbacks of these methods.

Trying virtual garments on a virtual body has become widespread in the design industry as a result of 3D computer-aided design (CAD) system and progress in body measurement systems. Spending less time and cost compared to traditional methods of garment design is the main benefit of design software development. Moreover, it leads to improved garment fitting on the body which fulfills customer desires. In the present study, a parametric graphical method was utilized to develop a 3D virtual mannequin for the pregnancy period. The former, the 3D adaptive mannequin model was predicted based on a woman&rsquo, s weight by analyzing body morphology evolution of a pregnant woman. The mannequin was verified by the results of another pregnant body. Then, the developed mannequin based on weight gain during maternity was applied to design a garment block pattern. The virtual try-on of the developed garment block pattern suggested that it was well-fitted on the 3D virtual mannequin while two armpit darts and two elastic seams were allocated. Hence, the developed garment block pattern will be used to make a personalized protective garment in our future work using an electromagnetic shielding woven fabric formerly manufactured by our group.

International audience; Textiles have been highly considered in applications of electromagnetic shielding effectiveness. This is mainly due to an increasing concern of health issues caused by human exposure to radiation. In the present study, the main objective was to develop a monofilament yarn made of conductive polymer composite (CPC) for electromagnetic shielding application to decline the drawbacks of previous electromagnetic shielding textile products. Thus, CPCs were produced by melt mixing method, using Polyamide 6,6 (PA6,6) as matrix and carbon black (CB) or/and multiwall carbon nanotube (MWCNT) as conductive nanofillers and the synergy effects of CB and MWCNT on electrical conductivity was studied. Consequently, 1.7 wt.% of MWCNT and 3.3 wt.% of CB (1MWCNT:2CB) was applied to generate a PA6,6-based composite at the critical percolation threshold while its electrical conductivity was higher than the PA6,6-based composite contained 20 wt.% of CB and the same as the one contained 3 wt.% of MWCNT. The developed monofilament is lightweight, corrosion resistant and the manufacturing process is very well established in comparison with metal yarns. These characteristics make it an alternative to produce electromagnetic shielding clothing for personal protection. Thus, the developed monofilament was woven to fabricate an electromagnetic shield fabric and the electromagnetic shielding effectiveness was evaluated in the frequency range 1-10 GHz. In brief, the electrical conductivity was improved using the synergism between nanofillers while the viscosity was in the standard range for monofilament making process by extrusion. Moreover, the shielding effectiveness (SE) of the woven sample made of the developed composite was promising for personal protection (16 dB).

Flame retardancy of polymers is a recurring obligation for many applications. The development trend of biobased materials is no exception to this rule, and solutions of flame retardants from agro-resources give an advantage. Lignin is produced as a waste by-product from some industries, and can be used in the intumescent formation development as a source of carbon combined with an acid source. In this study, the flame retardancy of polyamide 11 (PA) is carried out by extrusion with a kraft lignin (KL) and ammonium polyphosphate (AP). The study of the optimal ratio between the KL and the AP makes it possible to optimize the fire properties as well as to reduce the cost and facilitates the implementation of the blend by a melting process. The properties of thermal decomposition and the fire reaction have been studied by thermogravimetric analyzes, pyrolysis combustion flow calorimetry (PCFC) and vertical flame spread tests (UL94). KL permits a charring effect delaying thermal degradation and decreases by 66% the peak of heat release rate in comparison with raw PA. The fire reaction of the ternary blends is improved even if KL-AP association does not have a synergy effect. The 25/75 and 33/67 KL/AP ratios in PA give an intumescence behavior under flame exposure.

In this study, two different types of industrial lignin (i.e., lignosulphonate lignin (LL) and kraft lignin (DL)) were exploited as charring agents with phosphorus-based flame retardants for polyamide 11 (PA11). The effect of lignins on the thermal stability and fire behavior of PA11 combined with phosphinate additives (namely, aluminum phosphinate (AlP) and zinc phosphinate (ZnP)) has been studied by thermogravimetric analysis (TGA), UL 94 vertical flame spread, and cone calorimetry tests. Various blends of flame retarded PA11 were prepared by melt process using a twin-screw extruder. Thermogravimetric analyses showed that the LL containing ternary blends are able to provide higher thermal stability, as well as a developed char residue. The decomposition of the phosphinates led to the formation of phosphate compounds in the condensed phase, which promotes the formation of a stable char. Flammability tests showed that LL/ZnP ternary blends were able to achieve self-extinction and V-1 classification, the other formulations showed a strong melt dripping and higher burning. In addition to this, cone calorimetry results showed that the most enhanced behavior was found when 10 wt % of LL and AlP were combined, which strongly reduced PHRR (&minus, 74%) and THR (&minus, 22%), due to the interaction between LL and AlP, which not only promotes char formation but also confers the stability to char in the condensed phase.

Despite their chemical inertness and poor hydrophilicity, carbon-based materials are widely used in electrochemical applications due to their robustness, good electrical conductivity and corrosion resistance. The purpose of the work carried was to increase the wettability of nonwoven carbon fiber felts for improved efficiency in bio/electrochemical applications. Virgin Carbon Felt (VCF) was first treated with cold remote plasma (CRP) using a mixture of nitrogen and oxygen (1 or 2%) as plasma gas. Bio-functionalization of the carbon felts with glucose oxidase (GOx) enzyme was then carried using physical adsorption method. FTIR and XPS analysis showed an integration of new oxygenated functional groups (C O and C O) as well as amines and amides on the surface of VCF treated by the CRP treatment, which improved the wettability of the samples. Capillary uptake increased from around 0% (for VCF) to nearly 750% with 2% oxygen in plasma gas. GOx enzyme showed higher activity after immobilization at pH 5.5 on the CRP treated samples, maintaining up to 50% of its initial enzymatic activity after six cycles while with the VCF, no enzymatic activity was observed after the fourth cycle. These obtained felts can be used as electrodes in sustainable bioprocesses.

In this paper, the ability to 3D print lithium-ion batteries through Pmnbspace thermoplastic material extrusion and polymer powder bed fusion is considered. Focused on the formulation of positive electrodes composed of polypropylene, LiFePO4 as active material, and conductive additives, advantages and drawbacks of both additive manufacturing technologies, are thoroughly discussed from the electrochemical, electrical, morphological and mechanical perspectives. Based on these preliminary results, strategies to further optimize the electrochemical performances are proposed. Through a comprehensive modeling study, the enhanced electrochemical suitability at high current densities of various complex three-dimensional lithium-ion battery architectures, in comparison with classical two-dimensional planar design, is highlighted. Finally, the direct printing capability of the complete lithium-ion battery by means of multi-materials printing options processes is examined.

International audience; In this study, multifilament fibers based on neat poly(lactic acid) (PLA ), PLA /cellulose nanowhiskers (CNW s), and PLA /cellulose microcrystalline (MCC ) loaded at 1 and 3 wt.% were prepared by melt‐spinning process in the presence of PLA ‐grafted maleic anhydride (PLA ‐g‐ MA ) used as the compatibilizer and PEG as the plasticizer. This study showed that the incorporation of MCC in PLA matrix whatever the loading rate was not suitable for multifilament fibers spinning compared with CNW , due to the restricted drawability and a poor dispersion of the MCC within the PLA matrix. Furthermore, the whole characterization studies indicated that the incorporation of 1 wt.% of CNW in PLA with addition of the compatibilizer led to better thermal stability, flame retardancy, and multifilament tensile properties compared with neat PLA and with other filled PLA multifilament fibers.

Bicomponent fibers were melt spun to investigate the effect of individual component viscosity on the cross section morphology. Two couples were tested, polypropylene MFI 18 (PP18) with polyamide 6 (PA6) and, polypropylene MFI 25 (PP25) with polyamide 6 (PA6). Viscosity versus shear rates was evaluated by both rotational and capillary rheometers to cover a large range of shear rates. Higher viscosity of PA6 compared to PP25 and PP18 at the theoretical shear rate resulted in the encapsulation of PA6 by PP25 and PP18 at the periphery of the bicomponent fiber cross section. Interfacial instability from the center to the periphery fiber was explained as a result of non-uniformity of shear rates across the fiber cross section. Interface shape dependency on the viscosity ratio of the two polymers has been clearly demonstrated: lower viscosity component wrapping around the higher viscosity one whatever the initial configuration, that is, side-by-side or segmented pie structure.

Novel semi-conductive fibres from multiwalled carbon nanotubes (MWCNT) based-polyethersulfone (PES) have been produced by wet spinning insight of incorporation in composite matrix. N-methyl-2-pyrrolidone (NMP) was chosen as dispersing medium for MWCNT by sonication and as solvent for PES. MWCNT reinforced-PES fibres were spun into water coagulation bath with an observed instantaneous liquid-liquid demixing. After washing and drying steps, fibres are either directly characterized or annealed at 250 °C during 15 min and 24 h prior to characterization. Scanning electron microscope (SEM) micrographs performed in each configuration disclose presence of macrovoids, pores and empty spaces inside fibres before thermal annealing whereas after thermal annealing, fibres display a cohesive and continuous morphology. A significant mechanical properties improvement of the wet-spun fibres is noticed by rising annealing time. Transmission electron microscope (TEM) investigations have also been carried out and reveal a two phases microstructure in unannealed fibres with a separation between a PES-rich continuous phase and NMP-rich nodules containing exclusively MWCNT. TEM images suggest also thermal annealing process allows solvent evaporation, MWCNT aggregation and a conductive nanofillers network formation in PES nanocomposite fibres. Electrical measurement in unannealed fibres indicate a deficiency of conductive character between 0.25 and 2 wt.% MWCNT whereas a lowering electrical percolation threshold is achieved in fibres by increasing annealing time, around 1.5 and 1 wt.% MWCNT for respectively a 15 min and 24 h thermal annealing. Influence of MWCNT sonication duration on electrical conductivity is also examined showing a gradually reduction of fibres' electrical conductivity by dispersion time increasing until losing their semi-conductive state. A dispersion analysis let suppose that a whole MWCNT agglomerates network is split in smaller but denser clusters which are dispersed and taken away from each other during sonication, which causes the conductive path rupture.

Microfibers can be obtained by bicomponent spinning, followed by subsequent mechanical splitting. During process, two materials are coextruded in a die to form a unique complex morphology. Many factors affect these morphologies: melt viscosity and difference of crystallization temperature combined with polymers position. Consequently, fiber splitting can be improved by choosing an association of polymers with a stable interface and a poor adhesion. The aim of this study is to understand which intrinsic parameters of polymers allow to enhance bicomponent fiber's splitting. Bicomponent fibers (side-by-side and sheath/core) have been made with two grades of polypropylene and polyamide 6. Instable interface happens when a low-viscosity polymer flows around and encapsulates a high-viscosity material. Possible mechanism responsible of interface deformation is variation of shear rates through the morphology (highest shear rate is at the fiber periphery). DMA analysis reveals that fiber with polyamide as core exceeds the strength of fiber with polyamide as sheath. This increase of strength can be attributed to a better adhesion than fibers with PA6 in sheath. From experimental results, the position combined with the difference crystallization temperature shows poor or strong interface.

By incorporating electrically conductive yarns into a waterproof membrane, one can detect epoxy resin cracking or liquid leakage. Therefore, this study examined the electrical conductivity variations of several yarns (metallic or carbon-based) for cracking and water detection. The first observations concerned the detectors&rsquo, feasibility by investigating their conductivity variations during both their resin implementation processes and their resin cracking. Throughout this experiment, two phenomena were detected: the compression and the separation of the fibres by the resin. In addition, the resin cracking had an important role in decreasing the yarns&rsquo, conductivity. The second part of this study concerned water detection. Two principles were established and implemented, first with yarns and then with yarns incorporated into the resin. First, the principle of absorption was based on the conductivity variation with the yarns&rsquo, swelling after contact with water. A short circuit was established by the creation of a conductive path when a drop of water was deposited between two conductive, parallel yarns. Through the influence of the yarns&rsquo, properties, this study explored the metallic yarns&rsquo, capacity to better detect water with a short circuit and the ability of the carbon-based yarns to detect water by the principle of absorption.

This study investigates the influence of various lignins and their content on the thermal stability and fire retardancy of biobased polyamide 11 (PA). Microcomposites based on PA and containing 5, 10, 15, and 20 wt % different lignins were prepared with a twin-screw extruder. Morphological analysis showed good interfacial interaction and uniform distribution of lignin particles within the resulting microcomposites. Further, thermogravimetric analyses carried out in inert atmosphere indicated that, unlike kraft lignin, which is able to give rise to the formation of lower char residue (41–48 wt % at 600 °C), the sulfonated counterpart provides a higher thermal stability as well as a higher char residue (55–58 wt %). Furthermore, vertical flame spread tests clearly showed that 15 wt % is the optimum of kraft or sulfonated lignin loading to achieve improved flame retardant properties and a V1 rating. In addition, a cone calorimeter was exploited to study forced combustion behavior; in particular the microcomp...

In many application fields, such as medicine or sports, heating textiles use electrically conductive multifilaments. This multifilament can be developed from conductive polymer composites (CPC), which are blends of an insulating polymer filled with electrically conductive particles. However, this multifilament must have filler content above the percolation threshold, which leads to an increase of the viscosity and problems during the melt spinning process. Immiscible blends between two polymers (one being a CPC) can be used to allow the reduction of the global filler content if each polymer is co-continuous with a selective localization of the fillers in only one polymer. In this study, three immiscible blends were developed between polypropylene, polyethylene terephthalate, or polyamide 6 and a filled polycaprolactone with carbon nanotubes. The morphology of each blend at different ratios was studied using models of co-continuity and prediction of fillers localization according to viscosity, interfacial energy, elastic modulus, and loss factor of each polymer. This theoretical approach was compared to experimental values to find out differences between methods. The electrical properties (electrical conductivity and Joule effect) were also studied. The co-continuity, the selective localization in the polycaprolactone, and the Joule effect were only exhibited by the polypropylene/filled polycaprolactone 50/50 wt.%.

Increasing wettability of carbon felts is an important strategy to improve their efficiency in bio‐electrochemical applications. Herein, influence of cold remote plasma (N2 + O2) treatment on surfa ...

Two sets of compound woven fabrics containing three layers of simple woven fabrics were manufactured (five samples made of cotton yarns and five samples with one-third hybrid cotton/silver yarns). The thermal resistance and water vapor permeability of all the fabrics were measured and compared. It should be noted that the small dissimilarity in the thickness of the manufactured fabrics was due to the movement of the yarns through the thickness in the relaxing state of the fabrics. However, they were designed in a way to have the same thickness on the weaving loom. The results stated that the thermal resistance of asymmetric fabrics for both sets of fabrics (with and without silver) was different regarding which exterior face (face or back) was in contact with the hot plate (20°C). It should be noted that the fabric is not symmetric through its thickness due to the dissimilarity of weave pattern of the layers or the orientation of silver yarns. It affirms that the internal voids of each ply (which is correlated to the wave pattern) play a significant role in thermal resistance of the manufactured compound woven fabrics. As a result, the asymmetry of a compound woven fabric throughout the thickness makes it a potential fabric to be applied as double-face fabric for different climate conditions as the order of the layers changed the thermal resistance of the compound fabric due to the porosity of each ply. Furthermore, a reduction was observed in thermal resistance for the fabrics with silver presence (~40%) while the other parameters remained unchanged (e.g. yarn density, fabric structure, and fabric porosity). The reason is correlated to the high conductivity of silver as conductive materials improve the heat transfer of the fabrics. Moreover, the influence of silver presence on water vapor permeability was not significant although the water vapor permeability was slightly increased for the fabrics having silver in their structures.

Polyethersulfone (PES) and phenoxy based-nanocomposites filled with unmodified multi-walled carbon nanotubes (MWCNT) from 0.25 to 10 wt.% have been prepared by melt processing with a twin-screw extruder and a hot press. A morphology analysis is performed by transmission electron microscopy (TEM) in the extruded nanocomposites disclosing difference in state of dispersion despite a proper MWCNT scattering in both matrixes. The electrical conductivity measurements establish a percolation threshold Φ c = 0.58 wt.% and a critical exponent t = 2.3 for phenoxy against Φ c = 0.89 wt.% and t = 1.89 for PES-based composites by following a percolation scaling law of the form σ = σ 0 ( Φ − Φ c ) t . Thermal conductivity assessments as function of MWCNT concentration and temperature is then carried out by modulated temperature dynamic scanning calorimetry (MDSC) in both nanocomposites. In analogy with the electrical properties, no thermal percolation behaviour is pointed out despite noteworthy increases above 1 wt.% MWCNT incorporated in PES and phenoxy and temperature dependence below glass transition temperature. The effect of gas purge is also considered and reveals to be meaningful in relation with the thermal conductivity values of MWCNT-reinforced PES and phenoxy nanocomposites. Afterwards, a comparison of the DSC technique results byMDSC is performed with a thermal conductivity measurement using a Hot Disk transient technique showing significant discordance in experimental data, sometimes over the range of ±15%.

Using bio-based polymers to replace of polymers from petrochemicals in the manufacture of textile fibers is a possible way to improve sustainable development for the textile industry. Polylactic acid (PLA) is one of the available bio-based polymers. One way to improve the fire behavior of this bio-based polymer is to add an intumescent formulation mainly composed of acid and carbon sources. In order to optimize the amount of bio-based product in the final material composition, lignin from wood waste was selected as the carbon source. Different formulations of and/or ammonium polyphosphate (AP) were prepared by melt extrusion and then hot-pressed into sheets. The thermal properties (thermogravimetric analyses (TGA) and differential scanning calorimetry (DSC)) and fire properties (UL-94) were measured. The spinnability of the various composites was evaluated. The mechanical properties and physical aspect (microscopy) of PLA multifilaments with lignin (LK) were checked. A PLA multifilament with up to 10 wt % of intumescent formulation was processed, and the fire behavior of PLA fabrics with lignin/AP formulation was studied by cone calorimeter.

A lightguide fibre–based textile collecting and delivering sun energy is developed. It aims to dramatically reduce the amount of photovoltaic cells embedded on some devices and thus competes with current organic photovoltaic cell technology. However, the use of a woven textile implies a specific and unconventional configuration of light entrance, the light being collected along the fibre length. Hence, it raises numerous challenges in terms of light collection and propagation. This study reviews the literature, exposes and addresses these challenges. Several woven structures are tested using a filtered xenon lamp to simulate the sun and a specially designed test bench. The textile's light weight and efficiency are considered since they are both significant assessment criteria.

Nanocomposites based on Poly ((hydroxy ether) of bisphenol A) (Phenoxy) filled with multiwalled carbon nanotubes has been prepared by extrusion. Rheological behaviour and thermal degradation of these nanocomposites have been studied by melt flow index and thermogravimetric analysis. The results show that the addition of carbon nanotubes up to 2wt% increases the viscosity but does not modify significantly the spinnability of the compounds. Moreover, incorporation of these nanofillers allows an improvement of the thermal decomposition. In a second step, these nanocomposites have been processed by melt spinning to produce multifilament yarn. Transmission electron microscopy observations have been done to study carbon nanotubes dispersion and orientation. Nanocomposite morphology correlated with electrical measurements reveal an electrical percolation around 1.5 wt.% without decreasing significantly mechanical properties.