Multifilament Yarns Research Articles

Accelerated Degradation of Poly(lactide acid)/Poly(hydroxybutyrate) (PLA/PHB) Yarns/Fabrics by UV and O2 Exposure in South China Seawater.

Marine plastic pollution is emerging as a potential hazard to global ecosystems and human health. Micro-fibers derived from synthetic textiles contribute a considerable proportion of plastic debris. Bio-polymers/bio-plastics have been proposed for the application of apparel products, yet their degradability, fate, durability and related environmental parameters are still elusive and need further exploration. Herein, we report the degradation behavior of poly(lactide acid)/poly(hydroxybutyrate) (PLA/PHB) fabrics, made from PLA/PHB multi-filament yarns, in subtropics marine seawater. The degradation experiments were performed under various parallel conditions including static seawater, aerobic seawater in dark box, aerobic seawater under sunlight, static seawater under ultra-violet light and aerobic seawater under ultra-violet light. Continuous mass loss of PLA/PHB fabrics as the immersion time in the seawater increased was confirmed. The hydrolysis rate of PLA/PHB fabrics accelerated in the presence of UV light and dissolved oxygen in the seawater. Moreover, the tensile strength of the PLA/PHB yarns dropped rapidly by 38.54–68.70% in spite of the mass loss percentage being from 9.57% to 14.48% after 2 weeks’ immersion. All the PLA/PHB fabrics after two weeks’ immersion exhibited similar ATR-IR spectra. Therefore, the degradability of PLA/PHB fabrics, in the marine surface water under the synergistic destructive effect of seawater, UV and dissolved oxygen, provides a pathway for more sustainable textile fibers and apparel products.

DETERMINATION OF TENSION FOR ARAMID AND CARBON YARNS WHILE WEAVING INDUSTRIAL FABRICS

Resulting from researches conducted to determine tension for para-aramid, meta-aramid, and carbon multifilament yarns during their contact with the operative parts of the weaving looms as part of the industrial fabrics formation process, we have found out that in threading areas the tension is increasing driven by variation of values of the friction forces in the contact area. It has been proven that tension degree of para-aramid, meta-aramid, and carbon multifilament yarns before industrial fabric formation area is influenced by (1) tension before cylindrical guide surface of an operative part, (2) radius of the cylindrical guide surface curve of the operative part, (3) contact angle between yarns and cylindrical guide surface of an operative part, (4) mechanical, physical and structural properties of para-aramid, metaaramid, and carbon multifilament yarns. It allowed (yet at the initial stage of design of technological process of industrial fabric formation) to determine para-aramid, meta-aramid, and carbon multifilament yarns tension before formation area depending on (1) form of threading line for yarns at the weaving loom, (2) mechanical, physical and structural properties of para-aramid, meta-aramid, and carbon multifilament yarns and industrial fabrics. The paper contains experimental research of interaction of para-aramid, metaaramid, and carbon multifilament yarns and cylindrical guide surfaces of the operative parts of automatic weaving looms. Based on experimental researches regression dependencies have been obtained between para-aramid, meta-aramid, and carbon multifilament yarns tension value after cylindrical guide surfaces of the operative part and (1) tension before cylindrical guide surface of the operative part, (2) radius of the cylindrical guide surface curve of the operative part, (3) contact angle between yarns and cylindrical guide surface of the operative part. Consecutive application of these regression dependencies allows to determine para-aramid, meta-aramid, and carbon multifilament yarns tension before industrial fabrics formation area. Analysis of regression dependencies allowed to find out values of technological parameters when para-aramid, meta-aramid, and carbon multifilament yarns tension before industrial fabrics formation area will be of minimum value. It will allow to minimize tension of para-aramid, metaaramid, and carbon multifilament yarns while manufacturing resulting in (1) yarn breakages reduction, (2) better productivity of weaving looms due to reduced stoppage time, (3) improved quality of manufactured industrial fabrics. Therefore, we can argue that suggested technological solutions are practically attractive. In view of this, it is reasonable to say that it is possible to directionally regulate the process of para-aramid, meta-aramid, and carbon multifilament yarns tension change while manufacturing industrial fabrics on the weaving looms through selection of values of guides’ geometrical parameters.

The responses of stitched ultra-high-molecular-weight polyethylene woven fabrics upon ballistic impact

This paper investigates the influence of thread stitching on the ballistic performance of plain weaves made of ultra-high-molecular-weight polyethylene multi-filament yarns. The inter-yarn friction is increased due to the constraint imparted by the sewing thread. The yarn pull-out test shows that the peak-load force of the sample with one stitching line is almost 10 times greater than that of the unstitched plain weave, and the maximum pull-out force increases with the loading rate. Ball-bearing impact tests are performed to characterize the ballistic performance of the stitched and the unstitched samples, and finite element simulation is used to study the underlying mechanisms of energy absorption. The ballistic penetration tests show that the stitched fabrics outperform the plain weave in terms of energy absorption. The most significant improvement in ballistic performance is observed in stitched panels where sample SL2T (a triple-ply plain fabric system stitched on every two yarns) exhibits a specific energy absorption over two times greater than that of multi-ply systems consisting of plain weaves. It is also found from the high-speed photography that thread stitching constrains the yarn displacement and therefore eliminates the possibility of yarn pull-out, enabling the primary yarns to be well-engaged with the projectile at low impact velocities and to be stretched to fail at high impact velocities. Numerical predictions show that thread stitching enlarges the area of stress distribution and widens the transverse deflection, making the stitched systems absorb more energy than the unstitched system shortly after impact.

A quantitative study of the influence of cement matrix impregnation on yarn pullout strength using combined confocal microscopy and double resin impregnation.

The complex impregnation of a multifilament yarn by a cementitious matrix leads to a difficult prediction of the mechanical behaviour of textile reinforced concrete and its less spread use than steel-reinforced concrete. To solve this problem, several models were established but they are not based on direct observations of the embedded yarn or quantification of its impregnation. In order to improve those models, a double resin impregnation process followed by confocal microscopy was set up, after pullout test was performed on each sample. Several parameters were then computed from the obtained images, which enables to quantify the impregnation of the yarn for each sample and to compare it with the pullout mechanical results. The number of fully impregnated filaments is found to be the crucial point to explain the pullout maximum load. The type of failure is also defined using those same parameters, computed along the embedded length, and it was found that the shape of the extracted volume of yarn is cylindrical and so the failure of the filaments is not telescopic. A pre-existing model was then improved, considering all those conclusions obtained by microscopic observations, and a good match between the numerical and the experimental results was found. Multifilament yarns are a continuous and flexible textile structure composed of hundreds of filaments that are maintain together using a chemical product called sizing. Those multifilament yarns can be used to reinforce mortar or concrete, like steel in steel-reinforced concrete. The performances of those types of composites depend strongly on the strength of the reinforcement/mortar bond. In case of textile /mortar composite, this bond depends on the level of penetration of the mortar into the yarn, so the impregnation of the yarn by the mortar. Since they are both very heterogeneous material, this impregnation is random and incomplete. Consequently, it is very difficult to predict the strength of this bond and so, the strength of the yarn/mortar composite. As a result, this type of composite cannot be widely used. Some models were established to predict the strength of those composite; however, they are not based on direct observation of the textile/mortar bond. To improve those models, a new visualisation method of the impregnation of the yarn by the mortar was set up. A double moulding of the impregnated yarn by the mortar was manufactured, using resins and two different fluorescent dyes, after underwent a mechanical test of pulling out the yarn from the mortar (pullout test). First, a resin with a red fluorescent dye was used for the moulding of the yarn shortly after the test, and, second, after dissolution of the mortar around the yarn in acid, a resin with a green fluorescent dye. A number of cross sections of the yarn is observed using a microscope that detects those two dyes and the obtained images are analysed allowing a clear differentiation, location and counting of fully impregnated filaments of the yarn by the mortar and those partially or not impregnated. The results are compared to the mechanical parameters of the pullout test. The number of fully impregnated filaments is found to be crucial to explain the strength of the composite. The behaviour during the pullout test is also explained using parameters computed along the length of the yarn in the mortar. It is found that filaments extracted by pulling-out take a cylindrical shape and so the pullout behaviour is not conical shape as it was suggested in a number of models. Considering all those conclusions obtained by observations, a pre-existing model is improved, and a good match between the numerical and experimental results is found.

Formation and Investigation of Mechanical, Thermal, Optical and Wetting Properties of Melt-Spun Multifilament Poly(lactic acid) Yarns with Added Rosins.

One method for adding enhancing properties to textile materials is the insertion of natural ingredients into the textile products during the manufacturing or finishing process. The aim of this research is to investigate the formation of biodegradable melt-spun multifilament Poly(lactic acid) (PLA) yarns with different contents (i.e., 5%, 10%, and 15%) of natural material–rosin, also known as colophony. In this study, multifilament yarns were successfully formed from PLA and a natural substance–pine rosin by melt-spinning them at two different draw ratios (i.e., 1.75 and 2.75). The results indicated that a 1.75 draw ratio caused the formation of PLA and PLA/rosin yarns that were brittle. The presence of rosin (i.e., 5% and 10%) in multifilament yarns decreased the mechanical properties of the PLA/rosin melt-spun multifilament yarns’ tenacity (cN/tex), breaking tenacity (cN/tex), and tensile strain (%) and elongation at break (%) and increased absorbance in the entire UV region spectra. In addition, the melting point and degree of crystallinity decreased and there was an increase in the wetting angle compared with pure PLA multifilament. The investigation of melt-spun yarns with Raman spectroscopy proved the presence of rosin in PLA melt-spun yarns.

Effect of Stretching on Thermal Behaviour of Electro-Conductive Weft-Knitted Composite Fabrics.

This experiment presents a study carried out on the electric charge passing textiles for heat production in compression weft-knitted composite fabrics used for medical purposes. The aim was to flourish compression support of knitted structure with integrated highly sensitive metal (silver) coated polyamide multifilament yarns and to evaluate its heat origination attributes after stretching in different levels as well as changes of the temperature during the time. A flat double needle-bed knitting machine was utilized to fabricate the selected specimens together with elastomeric inlay-yarn incorporated into the structure for compression generation and silver coated polyamide yarn laid as ground yarn in a plated structure for heat generation. Six different variants depending on the metal coated yarn amount used and the fabric structure along with two types of the conductive yarn linear density were fabricated for this research work. Scanning electron microscope (SEM) images were preoccupied to show the morphology of conductive yarn and thermal pictures were captured to study the evenness of the heat over the surface of composite fabrics depending on conductive yarn distribution in the pattern repeat. The temperature profile of fabricated composite fabrics and comparison of the heat generation by specimens after stretching in different levels was studied

New visualization method to characterize the impregnation of a multifilament yarn in a cement matrix

New visualization method to characterize the impregnation of a multifilament yarn in a cement matrix

A numerical structure-based method of simulating filament yarns

Simulation of yarn and filament behavior is very important due to its role in optimizing the processes of producing different types of yarn. Virtual yarn models make it possible to simulate the behavior of fabrics more accurately and that of sewing yarns in seam lines more realistically. The structure of yarns is an important factor affecting their behavior. However, in most studies in the field of yarn simulation, the structure of yarns is ignored, and they are simulated as single strings. In this paper, a model is developed to simulate the behavior of multi-filament yarns based on a multi-string structure and the inter-string forces affected by tension and twist. To this end, the properties that affect a yarn structure, such as the number of filaments, the amount of twist as well as the material and the fineness of the filaments, are incorporated into the model. In order to investigate the validity and accuracy of the proposed model, the simulated behavior is compared to the behavior of real yarns in six different modes. The results show that the model is able to simulate the behavior of yarns with an average error of 5.73%, as compared to reality. In order to investigate the effects of the yarn structure and the corresponding inter-structural forces on the yarn simulation, the yarn behavior is simulated with several simple single-strand models in which inter-string forces are not taken into account. A comparison of the models shows that the proposed one is able to yield results closer to reality and reduce the simulation error averagely for 7.76%.

Engineering hybrid textile braids for tendon and ligament repair application

AbstractChallenges involving tendon and ligament repair have motivated the investigation of new strategies to improve clinical outcomes. These have been mainly based on polymer constructs, which may be non‐biodegradable or biodegradable. The former typically fails due to lack of device integration and the latter demands a complex balance between biodegradability and tissue ingrowth, often failing due to insufficient mechanical properties. This work presents the development of hybrid braids based on polyethylene terephthalate (PET) and polylactic acid (PLA) yarns. A textile technique was used to fabricate braids based on 16 multifilament yarns of varying PLA/PET composition. The composition was varied to maximize biodegradability while ensuring mechanical performance. The braids' morphology, physical and mechanical properties were characterized. As production parameters and architecture were maintained, the braids exhibited similar porosity and wicking ability. The breaking force and stiffness decreased significantly as the number of PLA yarns increased, although strain levels remained constant. Braids containing 10 and 12 PET yarns (out of the total 16 yarns) demonstrated good creep and force‐relaxation behavior, as well as resistance to cyclic loading. These compositions were selected for future work, to be assembled into more elaborate structures to mimic the fibrous organization and tensile properties of different tendons/ligaments.

Development of an Elastic, Electrically Conductive Coating for TPU Filaments.

Electrically conductive filaments are used in a wide variety of applications, for example, in smart textiles and soft robotics. Filaments that conduct electricity are required for the transmission of energy and information, but up until now, most electrically conductive fibers, filaments and wires offer low mechanical elongation. Therefore, they are not well suited for the implementation into elastomeric composites and textiles that are worn close to the human body and have to follow a wide range of movements. In order to overcome this issue, the presented study aims at the development of electrically conductive and elastic filaments based on a coating process suited for multifilament yarns made of thermoplastic polyurethane (TPU). The coating solution contains TPU, carbon nanotubes (CNT) and N-Methyl-2-pyrrolidone (NMP) with varied concentrations of solids and electrically conductive particles. After applying the coating to TPU multifilament yarns, the mechanical and electrical properties are analyzed. A special focus is given to the electromechanical behavior of the coated yarns under mechanical strain loading. It is determined that the electrical conductivity is maintained even at elongations of up to 100%.

Thermal, Mechanical and Chemical Analysis of Poly(vinyl alcohol) Multifilament and Braided Yarns.

Poly(vinyl alcohol) (PVA) in multifilament and braided yarns (BY) forms presents great potential for the design of numerous applications. However, such solutions fail to accomplish their requirements if the chemical and thermomechanical behaviour is not sufficiently known. Hence, a comprehensive characterisation of PVA multifilament and three BY architectures (6, 8, and 10 yarns) was performed involving the application of several techniques to evaluate the morphological, chemical, thermal, and mechanical features of those structures. Scanning electron microscopy (SEM) was used to reveal structural and morphological information. Differential thermal analysis (DTA) pointed out the glass transition temperature of PVA at 76 °C and the corresponding crystalline melting point at 210 °C. PVA BY exhibited higher tensile strength under monotonic quasi-static loading in comparison to their multifilament forms. Creep tests demonstrated that 6BY structures present the most deformable behaviour, while 8BY structures are the least deformable. Relaxation tests showed that 8BY architecture presents a more expressive variation of tensile stress, while 10BY offered the least. Dynamic mechanical analysis (DMA) revealed storage and loss moduli curves with similar transition peaks for the tested structures, except for the 10BY. Storage modulus is always four to six times higher than the loss modulus.

Effects of silver nanoparticle on mechanical properties of polylactide composite yarns with different structure

In this work, composite mono- and multifilament yarns of polylactide (PLA) containing 1 wt.% of commercial Poviargol (silver nanoparticles stabilized with poly(vinylpyrrolidone)) were prepared. The results of scanning electron microscopy revealed that filler particles are uniformly distributed inside PLA yarns, irrespective of sample type. It was also shown that, during spinning of monofilament yarns, the filler did not emerge to the yarn surface, whereas the surfaces of multifilament yarns were virtually strewn with silver nanoparticles. The analysis of antibacterial response demonstrated that the Poviargol-containing multifilament yarns, unlike the monofilament yarns, possessed antibacterial activity against the standard Staphylococcus aureus strain (dilutions 1 × 106 and 1 × 107 CFU/mL). Differential scanning calorimetry showed that the presence of 1 wt.% of Poviargol did not exert any influence on thermal performance and phase transitions in PLA. Finally, it was confirmed that Poviargol did not affect mechanical properties of monofilaments, and although its presence caused a certain decrease in mechanical strength of multifilaments, this difference did not exceed 15%.

Design, Development, and Characterization of Advanced Textile Structural Hollow Composites.

The research is focused on the design and development of woven textile-based structural hollow composites. E-Glass and high tenacity polyester multifilament yarns were used to produce various woven constructions. Yarn produced from cotton shoddy (fibers extracted from waste textiles) was used to develop hybrid preforms. In this study, unidirectional (UD), two-dimensional (2D), and three-dimensional (3D) fabric preforms were designed and developed. Further, 3D woven spacer fabric preforms with single-layer woven cross-links having four different geometrical shapes were produced. The performance of the woven cross-linked spacer structure was compared with the sandwich structure connected with the core pile yarns (SPY). Furthermore, three different types of cotton shoddy yarn-based fabric structures were developed. The first is unidirectional (UD), the second is 2D all-waste cotton fabric, and the third is a 2D hybrid fabric with waste cotton yarn in the warp and glass multifilament yarn in the weft. The UD, 2D, and 3D woven fabric-reinforced composites were produced using the vacuum-assisted resin infusion technique. The spacer woven structures were converted to composites by inserting wooden blocks with an appropriate size and wrapped with a Teflon sheet into the hollow space before resin application. A vacuum-assisted resin infusion technique was used to produce spacer woven composites. While changing the reinforcement from chopped fibers to 3D fabric, its modulus and ductility increase substantially. It was established that the number of crossover points in the weave structures offered excellent association with the impact energy absorption and formability behavior, which are important for many applications including automobiles, wind energy, marine and aerospace. Mechanical characterization of honeycomb composites with different cell sizes, opening angles and wall lengths revealed that the specific compression energy is higher for regular honeycomb structures with smaller cell sizes and a higher number of layers, keeping constant thickness.

CHARACTERIZATION OF AIRBORNE PARTICLES IN MECHANICAL TEXTILE YARNS PROCESSING

Nano and micro plastics (NP/MPs) represent one of the most challenging classes of micropollutants, with occurrence across all ecosystems and size distributions ranging from the nanometre to the millimetre scale. Natural environments are receiving MPs in the form of anthropogenic direct release as well as disintegrated and loose products of larger plastics via biological activities, mechanical abrasion, and UV radiation. During the processing steps, the textile yarns are subjected to friction either by different driving organs or between themselves at the binding points. The magnitude of the friction forces is influenced by the nature of the yarns, the structure of the yarn, the type, and the raw material from which the driving organs of the machines are made. The paper presents the shape and dimensions of the particle that is released in the air during the abrasion resistance test of three types of polyester yarns: spun yarn, multifilament yarn, and monofilament yarn. The structure composition of the particles consists of more microfibrils (34%.) in the case of spun yarn and the finest microparticles were obtain from monofilament yarn (0,004μm).

Tensile behavior of carbon textile concrete composite captured using a probabilistic multiscale multiple cracking model

The fast growing amount of high-performance textile fabrics made of carbon, glass and basalt yarns open up enormous design scope for cementitious composites, that needs to be sorted and graded using novel characterization procedures. A combined experimental and numerical characterization method of the composite tensile behavior is presented here for concrete reinforced with non-impregnated carbon textile fabrics. Because of the heterogeneous structure of the bond layer, which consists of a non-impregnated multifilament yarn partially penetrated by the cement paste, this material combination poses particularly high demands on a realistic modeling approach. It is well known, that the tensile response of strain-hardening brittle-matrix composites is primarily shaped by the multiple cracking process of the matrix. To account also for the local damage developing in the heterogeneous bond layer ahead of a crack bridge during the multiple cracking process, we combine a probabilistic crack bridge model with a generalized version of a crack tracing algorithm reflecting the random matrix strength. The resulting probabilistic multiscale multiple cracking model has been calibrated and validated using a consistent series of crack bridge and composite tensile tests by comparing the predicted and measured stress–strain curves and crack spacing histories. The efficient, flexible and realistic modeling concept can serve as a basis for the development of rapid characterization methods and more economic and reliable design rules.

Reverse engineering for estimation of shear modulus for yarn models in finite element modelling for ballistic impact

In finite element (FE) modelling of ballistic performance of fabric, shear moduli of continuous yarn models are usually specified based on approximations and assumptions, despite their significant influence on energy absorption and yarn failure time in a ballistic impact event. This paper applies reverse engineering method for estimating shear modulus G13 of a continuous multifilament yarn model for simulating the ballistic behaviour of the yarn or its fabric. A ballistic event of Dyneema® SK65 yarn model impacted by a projectile travelling at 477 m/s is used to illustrate the establishment of the methodology. The procedure starts by relating G13 and transverse wave velocity (ut) through regression whose correlation factor R2 is 0.999. ut is calculated by the classical Smith equations. The regressed relation and the availability of ut value enable the calculation of G13. The simulated results of the Dyneema® yarn model with such estimated G13 show healthy agreements to the analytical and experimental counterparts in terms of ut and the slope angle of fabric deflection θ. The reverse engineering method has been used for obtaining G13 successfully for yarn models of other materials, e.g. Kevlar KM2 and Zylon®, in simulating their transverse deflection behaviour under the ballistic impact.

Development of 3D Models of Knits from Multi-Filament Ultra-Strong Yarns for Theoretical Modelling of Air Permeability

The work is devoted to the study of the geometric parameters of a knitted loop. It has been found that the optimal model is a loop model detailed at the yarn level, which considers the change in the cross-sectional shape and sets the properties of the porous material in accordance with the internal porosity of the yarn. A mathematical description of the coordinates of the characteristic points of the loop and an algorithm for calculating the coordinates of the control vertices of the second order spline, which determine the configuration of the yarn axes in the loop, are presented in this work. To create 3D models, Autodesk AutoCAD software and Structura 3D software, developed in the AutoLisp programming language, were used. The simulation of the air flow process was carried out in the Autodesk CFD Simulation environment. For the experimental investigation, plane knits from 44 tex × 3 linear density ultra-high molecular weight polyethylene yarns were produced, and their air permeability was tested according to Standard DSTU ISO 9237:2003. The results obtained during the laboratory experiment and simulation differed by less than 5%.

Bicomponent multifilament yarns of recycled poly(ethylene terephthalate) and nano-titanium dioxide for antibacterial carpet

Recycled poly(ethylene terephthalate) (RPET) multifilament yarns are used in carpet manufacturing as a way to reduce plastic waste. The conventional RPET carpet is however susceptible to bacterial accumulation. As a result, this research experimentally doped RPET with nano-structure titanium dioxide (nano-TiO2) to produce RPET/nano-TiO2 bicomponent multifilament yarns with antibacterial property. The experimental multifilament yarn structure consisted of two parts: neat RPET core and RPET/nano-TiO2 shell. The nano-TiO2 content in the shell was varied between 1 and 3 wt% and the core/shell (C/S) ratios between 90/10, 70/30, and 50/50 w/w. The effects of C/S ratio and nano-TiO2 content on the mechanical and antibacterial properties of bicomponent multifilament yarns were determined. The experimental results indicated that the C/S ratio had no effect on the tenacity and elongation at break. Meanwhile, the tenacity and elongation at break of bicomponent fibers increased with nano-TiO2 content in the shell. The TiO2-doped RPET bicomponent yarns effectively inhibited the growth of Escherichia coli and Staphylococcus aureus. The 90/10 bicomponent multifilament fiber with 3 wt% TiO2 achieved the highest antibacterial activity. The very high antibacterial activity was attributable to greater deposition of nano-TiO2 particles near and on the shell surface.

Polyester Yarns Reinforced by Nanoclays

In the present study, poly(ethylene terephthalate)-clay nanocomposite multifilament yarns were prepared using two commercial and four nanoclays synthesized from Resadiye Na-montmorillonite (Na-MMT). Two type multifilament yarns, i.e., fully drawn yarn (FDY) and partially oriented yarn (POY), were melt spun. The FDY yarns were prepared using pilot type Buschaert SpinBoy II CC melt spinning machine with a masterbatch feeding ratio of 4–5% in order to meet industrial machine requirements. The POY spinning was made on the Barmag industrial machine, and the POY yarn was subsequently texturized. All multifilament yarns were prepared via the masterbatch approach, similarly used for the preparation of colored dope dyed yarns. The mechanical properties, flame retardancy, thermal stability, and morphology of produced yarns on melt spinning experiments were analyzed and discussed along with the effect of nanoclay properties such as thermal stability, polymer-clay compatibility, and particle size distribution.

Improving the Dyeability of Polypropylene Fibers Using Nanoclay and Plasma Treatment

In this study, polypropylene (PP) and polypropylene/nanoclay composite multifilament yarns with different nanoclay contents were prepared by melt spinning. The knitted fabrics were then made from these yarns and subjected to oxygen plasma treatment for 5 min. The samples were dyed with a disperse dye and an acid dye and the color strength, color coordinates, and fastness properties of the dyed samples were compared. The effect of plasma treatment on the surface chemistry and morphology of the samples was evaluated using Fourier-transform infrared spectroscopy (FTIR) and atomic force microscopy (AFM) analyses, respectively. FTIR analysis confirmed the introduction of oxygen-containing groups on the surface of the plasma-treated samples. AFM images confirmed etching of the fibers, and the surface roughness of the fibers increased significantly after plasma treatment. The incorporation of nanoclay in the multifilament yarns improved the dyeability of the polypropylene/nanoclay composite fibers with disperse and acid dyes. The optimum amount of the nanoclay for obtaining the highest color strength was 2 wt% and 1 wt%, for dyeing with the disperse and acid dye, respectively. Plasma treatment enhanced the dyeability and fastness properties of the fibers. The highest K/S values obtained on plasma-treated PP/nanoclay samples were 1.27 and 10.88 for acid and disperse dyes, respectively. The fastness properties of the samples dyed with the acid dye were generally lower than those of dyed with the disperse dye. The highest washing, dry rubbing, and light fastness properties were obtained on plasma-treated and disperse-dyed PP/nanoclay (2 %) sample, which were 4–5, 3, and 5, respectively.