Hollow Polyester Research Articles

A sustainable recycling process and its life cycle assessment for valorising post-consumer textile materials for thermal insulation applications.

The textile industry along with construction, electronics and plastic generate huge amounts of waste posing challenges to the adoption of the circular economy. This research presents a sustainable and low-cost recycling technology for conversion of post-consumer textile (denim) wastes to useful insulation materials. To accomplish the objective, nonwoven materials were produced using varying proportions of post-consumer recycled denim (r-denim) fibre and hollow polyester (PET) fibre using different punch densities in the needle punching process. Kowalski, Cornell and Vining mixture design, a special type of design of experiments, was adopted to develop the samples. Developed nonwoven materials were characterised for thermal resistance and tensile properties. The results show that nonwoven materials containing the minimum proportion (20%) of r-denim fibres exhibited the highest thermal resistance (0.131 W-1m2K). However, by adjusting the process parameter of the nonwovens, that is, the punch density, the same thermal resistance (0.131 W-1m2K) is also achieved even with 39% r-denim fibres. Additionally, the nonwovens produced from this blend proportion (r-denim:PET = 39:61) demonstrate a reasonable strength of 2.43 cN/tex. Environmental benefits of the developed r-denim/PET nonwovens have been evaluated by the life cycle assessment approach. Results show that the use of ~40% r-denim fibre has reduced the environmental burden significantly. Therefore, the nonwoven materials produced from post-consumer textile wastes hold tremendous potential as an alternative to synthetic fibres in thermal insulation applications. This recycling approach has immense potential to contribute to the efficient utilisation of post-consumer textile waste materials paving the way for environmental sustainability.

Thermal properties of multi-layered seamed fabrics under wet state

PurposeIn experiments utilising sweat solution and distilled water, seamed ensembles performed less thermally efficiently than unseamed fabrics.Design/methodology/approachWater may not accurately reflect perspiration when testing multi-layered clothes for thermal comfort in wet state. Most researchers used water or sodium chloride (NaCl) to measure wet state thermal comfort. However, human perspiration is an extremely complex mixture of aqueous chemicals, including minerals, salts, lipids, urea and lactic acid. This study compares the effects of simulated sweat solution to distilled water on the thermal behaviour of a multi-layered fabric assembly with different seam patterns.FindingsExperiment results show that stitching decreases thermal resistance and thermal conductivity. Seam pattern of 10 cm diagonal spacing is more thermally resistant than 2.5 cm diagonal spacing. In comparison to that of simulated sweat, fabric that has been moistened with distilled water exhibits increased thermal conductivity. Hollow polyester wadding or micro polyester wadding as the intermediate layer exhibits greater thermal resistance than multi-layered construction with spacer fabric as middle layer.Originality/valueThis study considers human perspiration while designing protective clothing for wet thermal comfort.

Study of moisture management properties of tri-layer knitted fabrics made from hollow polyester, bamboo, spun polyester and polypropylene

Study of moisture management properties of tri-layer knitted fabrics made from hollow polyester, bamboo, spun polyester and polypropylene

Interfacial Adhesion between Textile Fibers and Clay Mortar

Short fiber–reinforced clay mortar is known as an important structural material in traditional and rural buildings because it not only provides superior mechanical properties but can also be easily produced by the rapid, low-cost molding process. The adhesion of the fibers to clay mortar has a significant role in the mechanical characteristics of fiber-reinforced mortar. In this study, interfacial shear stress (ISS) between nine different fibers and clay mortar was investigated by performing the Microbond test. Based on the findings, date palm fiber, hollow polyester, and polypropylene, respectively, demonstrated the highest degree of ISS with clay mortar; nevertheless, the lowest degree belonged to goat hair, acrylic, and wool, respectively. The critical lengths of the fibers to be embedded in the mortar as the short fiber reinforcements were calculated. The highest critical length belonged to glass fibers and date palm, respectively, and the lowest values belonged to acrylic, polyester, polypropylene, and wool, respectively.

Development and characterization of socks with improved anti-odour, thermo-regulating and handle properties

Due to awareness of the potential threats of spreading diseases, the demand for antimicrobial fabrics in the world market has grown significantly and, is, expected to increase the share of medical textiles in the future world market. The purpose of this study is to develop antibacterial socks with the application of silver particles and to study thermo- physiological properties as well as the evaluation of tactile sensory perceptions of treated socks against untreated socks. Socks, which are a necessary item of clothing, need to be comfortable and affordable. The materials used for this study are cotton and polyester fibre with three different cross-sectional shapes i.e., common Polyester (round shape), Coolmax (Channeled polyester) and Thermolite (Hollow polyester). Blend ratios with percentages of 80/20 Cotton/Polyester, 80/20 Cotton/Coolmax and 80/20 Cotton/Thermolite were used as main yarns in plain crew socks while elastane yarn is used in the same percentage in all developed socks. A comparison between the samples treated with silver particles and the corresponding control samples concerning the selected properties was done. The presence of particles on the treated fibre was confirmed through an SEM study. Testing of untreated and treated fabrics for antibacterial study and odour test was carried out and found significant. The thermo-physiological properties such as air permeability, relative water vapour permeability % and thermal resistance were also studied and found better results as compared to untreated samples. Later tactile sensorial comfort i.e., fabric hand value was compared which is improved for treated samples which makes the wearer comfortable hand feeling. These data present a great interest to socks manufacturers who can make better choices to manufacture, cost-effective anti-odour socks.

Sound absorption characteristics of agro-sourced kapok fibrous materials

In this work, a new band yarn woven (BYW) fabric has been developed to improve the sound absorption of kapok fibrous materials. BYW fabric materials were prepared by the interweaving of the normal hollow polyester yarn with new band yarn produced by wrapping the super thin nonwoven around a twisted fiber web. This soft, thin, lightweight fabric is promising to get the door of a wide variety of agro-sourced kapok fiber for sound absorption applications. The sound absorption of BYW fabric and the normal woven fabric have been compared, and the effects of fiber type, kapok fiber content, and airflow resistivity on sound absorption of BYW fabric materials have also been investigated. The results show that BYW fabric exhibited better sound absorption than the normal fabric, and it can be further enhanced when the band yarn was prepared from kapok fiber instead of hollow polyester or cotton fiber. The sound absorption can be improved with the increasing content of kapok fiber. Furthermore, a new sound absorption empirical model based on the Delany-Bazley model was developed. Calculated sound absorption coefficients obtained from the new model agreed well with measured results. Kapok fiber, exhibits higher hollowness and smaller fiber diameter than common natural fibers, and it presents promising prospect to reduce environmental noise pollution.

Studies on thermal comfort of multi-layered fabric assembly after wetting with sweat and distilled water

Textiles play a vital role in assuring the thermal stability of the human body. The absorption of perspiration or moisture from a humid environment might result in wet clothing. Protective and sports apparel are often wet when the wearer is involved in high level of activity; thereby affecting the comfort. In order to understand the comfort behaviour of textiles in wet state, most of the researchers used the distilled water or NaCl aqueous solution. However, human sweat is a very complex aqueous mixture of chemicals comprising of salts, lipids, urea, lactic acid, carbohydrates, and minerals. In the present study, the effect of simulated sweat solution on the thermal behaviour of multi-layered fabric assembly is studied and compared with that of distilled water. The multi-layered fabric assembly consists of breathable PU-coated nylon as an outer layer; polyester knitted fabric as an inner layer; and micro-polyester wadding/hollow-polyester wadding/spacer fabric as the middle layer. In addition, the inner layer (next to the skin) is also tested for thermal comfort for both dry and wet states. It is observed that thermal properties of fabrics are drastically affected under wet conditions. The inner layer of fabric wetted with distilled water shows higher thermal conductivity as compared to that wetted with simulated sweat. Among various multi-layered assemblies, the thermal resistance and thermal diffusion of multi-layered assembly having hollow polyester wadding as a middle layer is high as compared to that having spacer fabric in the middle, under both dry and wet conditions.

The normal incidence sound absorption of the thin band yarn woven fabric with kapok fiber

In order to increase kapok fiber content to improve the sound absorption of woven fabric materials with kapok fiber, the kapok fiber woven fabric materials with a new band yarn structure have been fabricated in this paper. The mass percent of kapok fiber in the band yarn woven fabric (BYW) materials can reach to 80%. Comparisons of sound absorption coefficients of BYW with different fiber, the normal plain woven fabrics and nonwoven have been made. The effects of kapok fiber content, woven weave, warp density and band yarn diameter on sound absorption of BYW materials have been studied. It is shown that BYW with kapok fiber have the better sound absorption in the frequency range of 125–1600 Hz than BYW with cotton or hollow polyester fiber. The higher kapok fiber content, the better sound absorption of BYW owing to the large lumen structure filled with air of kapok fiber. The smaller warp density or the larger band yarn diameter, the higher the kapok fiber content as a result of the more number of band yarn per unit length of fabric, yields the better sound absorption of BYW. In addition, BYW with plain weave has the better sound absorption than BYW with twill or honeycomb weave in the frequency range of 1250–1600 Hz, and the phenomenon is opposite in the frequency range of 400–1250 Hz owing to the thinner thickness of material.

Effect of layering sequence and ambient temperature on thermal insulation of multilayer high bulk nonwoven under extreme cold temperatures

In extreme cold weather clothing ensemble, multiple layers of high bulk nonwovens are used to provide thermal insulation to the wearer. In this work, the effect of layering sequence in multi-layered high bulk thermal bonded nonwoven assembly on its thermal resistance is evaluated experimentally under sub-zero temperatures. Two multi-layered nonwovens, one made up of 1.4 denier solid (1.4 D S), 6 denier hollow (6 D H) and 15 denier hollow (15 D H) and the second made up of 3 denier hollow (3 D H), 6 denier hollow (6 D H) and 15 denier hollow (15 D H) polyester fibres were studied. The experiments were performed in a climatic chamber in the temperature range of 310 K to 210 K. Numerical simulations were carried out assuming heat transfer through the nonwovens as one-dimensional coupled conduction-radiation. The numerical methodology was developed using theoretical relations available in the literature to estimate the steady-state temperature profiles through the nonwoven layers and were validated using experimental data. The concurrence of experimental and numerical temperature profiles justifies the numerical methodology adopted in this work. Thermal resistance provided by the high bulk nonwoven increases with a decrease in ambient temperature. It is found that the thermal conductivity of nonwoven layers decreases from inner-to outer layers at a given ambient temperature. The heat flux through nonwoven layers, overall thermal conductivity and the thermal resistance of multi-layer nonwoven are independent of layering sequence if the convective heat transfer is extremely low.

The effect of hollow polyester fiber additive on expansive clay soil

Controlling the swelling of expansive clay soils is always challenging for geotechnicians. In this study, the effect of hollow polyester fiber as an additive on the free swelling percentage and pressure reduction of bentonite clay is investigated experimentally. The fibers are employed in two forms of spread and concentrated. Fiber dosages of 0.2, 0.5, 1, and 1.5 are employed for the spread form and fiber columns with diameters of 1.2, 2 and 3.2 cm, are considered for the concentrated form with fiber column densities of 30 and 60 kg/m3. The obtained results show a significant improvement in the swelling behaviour of bentonite for both the spread and concentrated forms, with better performance for the later form. In which, higher densities and larger diameters of the fiber columns generally decreases the swelling percentage and pressure. The best improvement was observed in the concentrated form sample, with 60 kg/cm3 density and 3.2 cm diameter, with 19 and 57 percent reduction in swelling percentage and pressure, respectively.

Sound absorption of hollow polyester woven fabric with honeycomb weave

The thin lightweight honeycomb woven fabrics has the uneven effect on its both sides owing to the combination of warp and weft float yarns and plain weave. In this paper, the honeycomb woven fabrics with different weave repeat and warp density have been fabricated using hollow polyester warp and weft yarns. Their sound absorption have been measured by using the impedance tube method. The effects of weave repeat, warp density and back air gap on sound absorption have been studied. The results show that weave repeat and warp density have impact on the structural parameters including honeycomb cell area, thickness and bulk density and the interior pore parameters including the mean pore diameter and porosity, and then have impact on sound absorption of fabrics. The combination of honeycomb woven fabrics and back air gap can improve the sound absorption of fabrics and the sound absorption at low frequency further increase as the back air gaps increase.

Research on sound absorption properties of hydrogenated carboxyl nitrile rubber/four-hole hollow polyester fibre composites

A series composite was prepared by adding hydrogenated carboxyl nitrile rubber (abbreviated HXNBR) as the matrix and four-hole hollow polyester (abbreviated FHHPF) as the reinforcement. The sound absorption properties of these composites were studied. The results show that with the increasing of FHHPF quantity, the storage modulus increases and the loss factor decreases gradually. On the contrary, the sound absorption performance of the composite was improved continuously. Composite with 40% FHHPF in 1 mm thickness is the best. The sound absorption coefficient reached to 0.651 at 2500 Hz and the effective frequency range of absorption coefficient above 0.2 was 1750-2500 Hz. When the amount of FHHPF increased to 50%, negative effects of overuse shown up, that led to the decreasing of the sound absorption property. With a constant mass ratio 70/30 of HXNBR/FHHPF composite, the sound absorption performance can be enhanced by changing its thickness. However, the improvement was smaller after the thickness increased to 2 mm. When increasing the thickness above 2 mm, the improvement of sound absorption performance tended to move to the middle and low frequency. In the meantime, the tensile mechanical properties of the composite were significantly improved by adding FHHPF. Tensile tenacity was improved greatly and the breaking elongation is significantly decreased. The deformation of the composite was smaller and more stable, which was beneficial for the actual engineering practice.

Assessment of the effect of body pressure on the warmth retention in sleeping bags

Sleeping bags are a common type of personal protective equipment that maintains the individual’s comfort during rest in an open environment. One of the main purposes of utilizing sleeping bags is protection against cold weather in order to prevent body heat loss. However, during use, the exertion of body pressure on the sleeping bag may impact its protective performance. In this study, the influence of body pressure on the thermal insulation of two sleeping bags containing solid and hollow polyester fibers was investigated with consideration of body pressure in the head, shoulder, hips, and feet regions. Moreover, the sleeping bag layer’s thickness and compressibility variations were analyzed. The results revealed that both sleeping bag layers suffer from the thickness and thermal insulation reduction under body pressure, especially in the hip area. However, due to the entrapped air inside the fiber structure, hollow fibers presented enhanced thermal resistance.

The Effect of Dopant Type on The Morphology and Electrical Properties of Hollow Polyester Fabric

Intrinsically conducting polymers (ICPs) have been intensively the subject of research since these polymers have superlative electrical and thermophysical properties. Due to the low hydrogen content and aromatic structure, they show perfect chemical, thermal, and oxidative stability and are practically insoluble in all common solvents. Also these polymers are latently electrical conducting materials, especially when doped. Polypyrole (PPy) is a very promising conducting polymer. It can be in easy way processes and has many interesting electrical properties. Also ıt is chemically and thermally stable. Like many other fully aromatic polymers, PPy is an electrical insulator, however, when oxidized it becomes an electrical conductor.The conductivity of PPy strongly consists in the preparation technique, and on the polymer additives and can be increased by about two orders of magnitude. In this study, electrically conductive hollow fabrics were prepared via ın situ chemical polymerization method and scanning electron microscopy (SEM) and electrical properties of conductive hollow fabrics were invesigated.

Fabrication of bamboo-structure hollow polyester monofilaments for extraordinary compression properties

Owing to its special structure, bamboo can withstand larger load in nature. The novel structure of bamboo is a great example for exploring materials with excellent mechanical properties, though limited research in this area has been reported so far. In textiles, monofilaments with outstanding compression property are desired in the development of warp-knitted spacer fabrics for a range of applications. Herein, we use 3D printing method to fabricate polyester (PET) bamboo-structure monofilaments and study their compression properties. It has been found that bamboo-structure hollow monofilament undertakes more load per unit mass than solid and continuous hollow monofilaments, and the value of load per unit mass increases with the increase of the hollow part. FEM analysis has discovered that the compression behavior and the compression properties of the bamboo-structure monofilament are in accordance with that of spacer monofilament in warp-knitted spacer fabrics. Warp-knitted spacer monofilaments prepared from bamboo-structure hollow monofilament with a high percentage of hollow part undertake more load per unit mass, providing new opportunities on the design and development of warp-knitted spacer monofilament towards different applications.

Reduced Graphene Oxide Coated Hollow Polyester Fibers for Efficient Solar Steam Generation

Solar steam generation based on photothermal materials has emerged as a green and efficient technology for a broad variety of applications, such as solar energy harvesting, desalination, power generation, wastewater treatment, and so on. Herein, the fabrication of a kind of a novel photothermal material that is prepared by simple coating of reduced graphene oxide (rGO) onto commercial hollow polyester fibers (HPFs) for efficient solar steam generation is reported. The as‐resulted rGO‐wrapped HPFs possess a porous structure, low thermal conductivity (0.042 W m−1 k−1), and broad light absorption (85%), which satisfies the criterion for construction of ideal photothermal materials. As expected, a high solar‐thermal efficiency of ≈81% is obtained at 1 kW m−2 irradiation, showing great potential for practical applications based on high solar energy conversion efficiency and a simple and, in particular, scalable manufacturing process.

Mechanical properties of hollow polyester monofilament: Compression and tension behaviors

Comparative analysis has been performed on the mechanical properties of hollow and solid polyester monofilament with identical external diameter. Tensile test of hollow polyester monofilament was conducted to study the influence of hollow core and the manufacturing method on the tensile fracture mechanism of hollow monofilament. The compressive properties of hollow monofilament were determined to provide a bundle-compression method to study the behavior of hollow polyester monofilament under axial compressive loading and compare with solid one. The results show that the tensile property of the hollow monofilament has smaller breaking force and higher breaking elongation than solid monofilament in case of identical external diameter. Under compression loading, the solid monofilament show better compressive properties than hollow one with identical diameter. The hollow core only affects the values of compressive strain and stress, but it has no effect on the compression and deformation mechanism. The study results also show that the polyester monofilament can show better mechanical properties than the solid polyester monofilament for the same weight. This study can help to design the lighter textile materials with the hollow polyester monofilament.

Optimization of material and process parameters of fibrous quilt for comfortable heat loss from human body

Various quilt samples are prepared by carding (web formation) of three kinds of fibers viz. cotton, normal polyester and hollow polyester and stitching the webs with a covering fabric. Effects of various parameters such as fiber type, fiber fineness, mass per square meter of the quilt (g m−2), applied compression and temperature difference on thermal conductivity of the quilts are investigated. Comfortable heat loss from the human body is theoretically estimated (123.66–159.14 W m−2), and these parameters are optimized by employing 33 Box-Behnken response surface design and analysis of variance (ANOVA) to maintain the comfortable heat loss from human body by the quilts. One empirical model has been derived to predict heat loss through the quilts with the given quilt parameters. The empirical model helps to understand and design a quilt suitable for the use in a designated cold climate.

Investigation on the structure and mechanical properties of acoustic-absorbing composite laminates

This study designed a novel porous acoustic-absorbing composite laminates structure with reinforced mechanical properties. Three-dimensional crimped hollow polyester (3D CHPET) fiber and high resilience polyester (HRPET) fibers with various blending ratio were fabricated into porous base fabric. Kevlar woven plain fabric was embedded between HRPET/CHPET porous base fabrics to reinforce strength, which were combined through needle punching and thermal bonding process. Air permeability and tear strength of the acoustic-absorbing composite laminates were tested to evaluate the mechanical properties of the acoustic-absorbing composite laminates. The results showed that the acoustic-absorbing composite laminates exhibited a little higher air permeability after being thermal-treated. Tear strength of the thermal-treated composite laminates was also better than that without thermal treating.

Studies on the Melt Spinning Process of Square 8-hole Hollow Polyester Fibre

In this paper, the shape of the spinneret capillary was discussed, and optimized spinneret capillaries were successfully processed by a computer numerical control processing method which takes a C-shape silver electrode as the basic unit. Based on the optimised spinning process, a new type of square 8-hole hollow PET fibre was prepared by the experimental method.