NONWOVEN DEVELOPMENT BY THE MULTILAYER STRUCTURE

Skin substitutes are heterogeneous group of scaffolds (natural or synthetic) and cells. We hypothesize that nanofibers with layer composition made of polylactide (PLA) and sodium hyaluronate (HA) obtained using electrospinning method are a good matrix for cell adhesion and proliferation. Optimal conditions of electrospinning of PLA and HA nanofibers to create layered compositions (PLA membrane covered with HA nonwovens) were determined by modifying parameters such as the appropriate amount of solvents, polymer concentration, mixing temperature and electrospinning process conditions. By changing the parameters, it was possible to control the diameter and properties of both polymer fibers. The spinning solution were characterized by surface tension and rheology. A scanning electron microscope (SEM) was used to determine the morphology and fiber diameters: PLA and HA. Structure of the PLA/HA nonwoven was analyzed using spectroscopy (FTIR/ATR). Biocompatibility of the nonwoven with fibroblasts (ECM producers) was assessed in the in vitro conditions. The results showed that stable conditions for the formation of submicron PLA fibers were obtained using a 13% wt. solution of the polymer, dissolved in a 3:1 mixture of DCM:DMF at 45 °C. The hyaluronic fibers were prepared from a 12% wt. solution of the polymer dissolved in a 2:1 mixture of ammonia water and ethyl alcohol. All materials were biocompatible but to a different degree. The proposed laminate scaffold was characterized by a hydrophobic-hydrophilic domain surface with a maintained fiber size of both layers. The material positively underwent biocompatibility testing in contact with fibroblasts.

In the study, electromagnetic shielding efficiency (EMSE) absorption and reflectivity properties of fabric produced from staple stainless-steel fibres and recycled staple polyester fibres by carding and needling technologies were investigated. The bi-component core/sheath polyester fibres at a fixed ratio of 20% in producing all nonwoven fabrics were used. The staple stainless-steel fibres and recycled staple polyester fibres were blended at 13 different ratios such as 1%, 2.5%, 5%, 7.5%, 10%, 12.5%, 15%, 17.5%, 20%, 22.5%, 25%, 27.5%, 30%. The fibre webs were formed at wool type carding machine and then the folded webs were bonded mechanically with needle punching machines. Half of the produced nonwoven composite fabrics were bonded by thermal bonding technology with oven and calender machines. As the conductive fibres were costly, the study aimed to obtain optimum shielding effectiveness with the usage of minimum conductive fibres. Electromagnetic shielding properties, absorption and reflection characteristics of needle-punched nonwoven fabrics with calendered or un-calendered were performed by coaxial transmission line method according to ASTM-D4935-10 in the frequency range of 15 MHz to 3000 MHz. It is a known fact that electromagnetic shielding effectiveness increases with the increase in the amount of conductive fibre. It was found that nonwoven fabric produced with a usage of 17.5% stainless steel fibre has at least 90% electromagnetic shielding percentage in general use with 15 dB at a frequency of 1800 MHz. Increased stainless steel fibre content in nonwoven fabrics resulted in decreased nonwoven fabric thickness and tensile strength. Such a nonwoven composite material with electromagnetic shielding property could be used for construction and building applications.

The cotton stalks bast fiber was a new kind of natural cellulose fiber, the fibers had the similar properties as the flax fibers. Polylactic acid (PLA) is a class of biodegradable matrix material. As the flax fibers can be reinforced materials and then compounded with PLA, cotton stalks bast fibers as reinforced materials and PLA as matrix were used to make a kind of green and biodegradable composite in the experiment. The composites were prepared by mixing, molding and cold forming. Orthogonal experiment table including length of the fibers, mass fraction of PLA, molding temperature and molding pressure was devised. Then the tensile strength, flexural strength and impact strength were tested and the analysis of range and variance was done. The optimal processing condition was obtained as follows: length of the fibers was 6mm, mass fraction of PLA was 75%, molding temperature was 175°C and molding pressure was 12MPa. The result showed that the cotton stalks bast fibers reinforced PLA biodegradable composites had good mechanical properties. Through this study waste cotton stalks basts were turned into useful resources and provided a kind of environmentally friendly composites.

Developing new nonwoven fabrics from PVC/PET artificial leather waste could contribute to achieving global sustainability objectives while tackling environmental challenges. In this study, a new composite product made of polyvinyl chloride (PVC) polymer and polyethylene terephthalate (PET) fibers was developed via the mechanical recycling process. Initially, PVC-coated polyethylene terephthalate scraps derived from artificial leather fabric wastes were chipped, grinded and pulverized to obtain PVC/PET particles. Secondly, three blends with various ratios of PVC and PET were selected and subjected to the hot compression molding process (at 190°C for 2 min), in order to produce new composite fabric. As a final step, the obtained fabrics were evaluated in terms of their physico-mechanical properties, such as thickness, weight per unit area, tensile strength, elongation, tear strength, and abrasion resistance. Therefore, the tensile properties of PVC/PET (92.39%:6.15%) are superior, with the tensile strength reaching an impressive 40 N/mm 2 and elongation measuring 48%. Additionally, the results showed that nonwoven fabrics produced from 83.75% PVC and 15.77% PET had excellent tear strength. Thus, raising the PVC powder proportion culminated considerably enhancing the physicomechanical properties of the recycled nonwoven fabric. Nevertheless, a high proportion of PET fibers (72%) in the produced nonwoven fabrics significantly improved the wear resistance regarding weight loss and visual appearance. Based on these results, an innovative and effective approach for repurposing PVC/PET artificial leather waste was demonstrated, which aligns with the principles of eco-friendly sustainability and responsible economic development promoted worldwide.

This study investigates the development of biodegradable nonwoven fabrics utilizing Alpinia purpurata pseudo-stem fibres, bonded with poly lactic acid (PLA) through a thermal bonding process. Given the underutilization of Alpinia purpurata fibres, this research explores their potential for sustainable textile applications. The fibres were extracted via decortication and blended with PLA at varying mass ratios (90/10, 80/20, 70/30), followed by comprehensive characterization. Evaluations included fabric mass per unit area, thickness, air permeability, tensile strength, elongation, wetting time, moisture regain and surface morphology. The results indicate that increasing PLA content enhances tensile strength but reduces air permeability and water absorption. Conversely, a higher proportion of Alpinia purpurata fibres improves breathability and moisture regain. These findings demonstrate that Alpinia purpurata fibres, in combination with PLA, can produce nonwoven fabrics with tunable properties, offering promising potential for environmentally friendly textile applications.

This study proposes the exposure of nonwoven fabrics to carbon dioxide for bundling and packaging purposes. The proposed process, which utilizes the shrinking property of the nonwoven fabric during carbon dioxide exposure, is demonstrated on a polylactic acid (PLA) nonwoven fabric produced by the melt-blown method. Evaluating the shrinkage induced by carbon dioxide in PLA nonwoven fabrics with varying degrees of crystallinity, it was found that increasing the crystallinity decreases both the speed and amount of shrinkage. This process is potentially applicable as a simple, inexpensive, and environmentally friendly approach for packaging food and drug products.

The 3D needled C/SiC composites were fabricated by chemical vapor infiltration combined with liquid melt infiltration. The microstructure and compressive behavior of 3D needled C/SiC composites were investigated. The results indicated that the 3D needled C/SiC composites were composed of the layers of 0 ° non-woven fiber cloth, short fiber web, 90 ° non-woven fiber cloth, and needle fibers. The materials were composed of carbon fiber, PyC, Si, and SiC. SiC and Si were mostly distributed in the short fiber web layers. Local C/C units (local carbon fiber reinforced PyC) were formed in the fiber bundles of non-woven fiber cloth. A great deal of pores and cracks existed in the 3D needled C/SiC composites. The pores less than 10 μm were generally located in the non-woven cloth layers, while the big pores were in the short fiber web layers. The cracks were regularly presented in the Si and SiC region of the composites and were normal to the axial direction of the fiber bundles. The compressive strengths perpendicular and parallel to the non-woven fiber cloth were about 118±18 MPa and 260±41 MPa, respectively. The compressive fractography revealed stepwise fracture along fiber layers direction.

This article aims to formulations and properties of novel hybrid biomaterials containing unique four-phase combinations of polylactide (PLA), nanoclays, flax fibers, and coupling agents. A PLA-grafted maleic anhydride (PLA- g-MA) masterbatch containing 10 wt% PLA- g-MA was obtained by reactive extrusion and was further used, after dilution, as a coupling agent. In addition, three PLA masterbatches containing 10 wt% of three different grades of nanoclays, one untreated nanoclay and two organonanoclays, were also compounded. In a subsequent extrusion step, the nanoclay masterbatches were diluted in PLA down to 4 and 2 wt% while simultaneously incorporating in each one 20 wt% of short flax fibers. Those bio-nanocomposites were compounded without and with an equivalent content of PLA- g-MA, that is, with 4 and 2 wt%, respectively, through the dilution of 10 wt% PLA- g-MA masterbatch. The effects of the nanoclay chemistries, PLA- g-MA, and of flax fibers presence on the properties of bio-nanocomposite hybrid materials were investigated. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, rheology, mechanical properties (tension, flexural, and Izod impact), and reprocess ability tests were used to characterize the bio-nanocomposite hybrid materials. In a second step, PLA- g-MA was replaced by an epoxy/styrene/acrylic copolymer for comparison purpose of their respective effect in bio-nanocomposite performances. Mechanical properties of bio-nanocomposites containing the second coupling agent were also evaluated. The effect of the epoxy/styrene/acrylic copolymer is discussed in comparison with the effect of PLA- g-MA.

Printability versus durability in 3D-printed biocomposites: Unraveling the distinct roles of flax and hemp fibers in PLA-based filaments

Although the construction of superwettability materials for oil/water separation has been developed rapidly, the postprocess of the used separation materials themselves is still a thorny problem due to their nondegradation in the natural environment. In this work, we reported the functionalization of polylactic acid (PLA) nonwoven fabric as superoleophilic and superhydrophobic material for efficient treatment of oily wastewater with eco-friendly post-treatment due to the well-known biodegradable nature of PLA matrix.

The statistical distribution of the number of fiber intersections in a unit area is of great importance in determining the physical and mechanical properties of random fiber webs and the products produced. The distribution of the number of fiber intersections determines the non-uniformity of the basis weight and can be used in designing optimal control strategies relating to such physical properties as strength, elongation, air/water permeability, acoustics and filtering efficiencies of fiber webs and nonwoven fabrics. This paper developed a geometrical and probabilistic model for the number of fiber intersections in two-dimensional random fiber webs, where two distinct fiber lengths are mixed at varying ratios. This work is an extension of a previously derived paper where the model assumed that all fiber lengths are equal. Here, we present a geometrical probabilistic model, theories for deriving expectations and variances of the number of intersections in random fiber webs. The model and statistical parameters are validated through an extensive computer simulation study.

This paper presents the parametric investigation and optimization of various chemical treatment parameters that affect the mechanical performance of the green composite. The injection moulding method was used to produce the green composites using flax fibre (FF) and polylactic acid (PLA). The chemical parameters chosen to investigate their effects are chemical type (sodium hydroxide, sodium carbonate, and potassium hydroxide), chemical concentrations (1 %, 2 %, and 3 % (w/v)), and duration for fibre treatment (2 h, 4 h, and 6 h). The mechanical performance of the green composites was assessed by evaluating the various properties namely strength, modulus, and elongation under tensile, share, flexural, and compression loading conditions. The morphological study was also performed to examine the failure behavior of the composite after mechanical testing. The effect of fibre length (2 mm, 3 mm, 4 mm, 5 mm, and 6 mm) and fibre loading (10 wt.%, 20 wt.%, and 30 wt.%) on the performance of the flax fibre (FF)/polylactic acid (PLA) composite was also investigated. The fibre dispersion, fibre orientation, and fibre length retention were investigated to assess the characteristics of fibre during injection moulding of the developed flax fibre (FF)/polylactic acid (PLA) composite.

ABSTRACTBiocomposites are sustainable alternatives to conventional composites due to their biodegradability and renewability. This study investigates the mechanical properties of 3D‐printed flax fiber‐reinforced polylactic acid (PLA) composites with fiber weight fractions ranging from 0% to 5%, and examines the effects of a 2% (w/v) sodium hydroxide solution treatment on the composite properties. Adding untreated fiber reduces the mechanical properties of single filaments, while the addition of treated fiber improves tensile strength by 16% and tensile modulus by 14% with up to 5 wt.% flax fiber content in the biocomposite. The treated fibers significantly increase the stiffness of the 3D‐printed samples, with an 81% rise in Young's modulus. Compared to pure PLA samples, a 41% improvement is observed with 2.5 wt.% content of treated flax fiber. However, tensile strength decreases by 35% across all samples, with greater reductions following treatment. Compression tests show a 23% strength increase for samples with untreated fibers, but performance declines with chemical treatment. Microscopic images reveal voids that impact mechanical properties, while Fourier‐transform infrared spectroscopy confirms the effects of fiber surface modification. These findings highlight the trade‐offs between improving stiffness and reducing strength when pre‐treatment of flax fibers are used, and underscore the potential of flax fiber‐reinforced PLA biocomposites in sustainable additive manufacturing for environmentally‐benign a advanced material production.

Ecological environment deteriorates drastically and rapidly, which can be ascribed to the fast advancement of international economy and technique. Hence, people become green consumers, using green products. The series of lyocell fiber, called as recycled fiber, has been pervasively used. This study used Tencel® fiber, Polylactic Acid (PLA) fiber and high absorbent fiber as well as nonwoven manufacturing, creating Tencel®/PLA/HAF composite nonwoven fabrics. Among the manufacturing parameters, an increase in Tencel® fiber ratio, needle-punching density and basis weight all contributed to heighten the mechanical properties of nonwoven fabrics. In particular, the Tencel®/PLA/HAF composite nonwoven fabric exhibited an optimum tensile strength of 68.8 N and bursting strength of 193.7 N when Tencel® fiber ratio was over 80 wt%, basis weight was 200 g/m2 and needle-punching density was 300 needle/cm2.

A hot compaction method has been used to form all-PLA composites by partial melting and fusion of fibres in non-woven mats where the matrix phase is formed from partially melted fibres and the reinforcement phase is the original PLA fibres that remain. Compaction required a minimum of 10 min heating at temperature range 172°C to 176°C under a load of 2.4 MPa. An advantage is that the oriented high tensile strength fibre properties are retained, while matrix adhesion is strong because melt adhesion is provided by the same polymer. The all-PLA composite structure was confirmed using scanning electron microscopy (SEM) and wide-angle X-ray scattering. Mechanical properties were evaluated from modulated force thermo-mechanical analysis. The temperature window below melting temperature of PLA of about at 172°C to 176°C was found as the optimum temperature for all-PLA composites with optimum properties. SEM study also shown the gaps between the fibers are filled with recrystallised material that has melted from the original fibres.