Polymer Fabrics Research Articles

Experimental and finite element analysis of flexural performance of RC beams retrofitted using near-surface mounted with CFRP composites and cement adhesive

Fiber reinforced polymer (FRP) composite has been used effectively for the rehabilitation of concrete and steel structures in the last decades due to its excellent properties compared with conventional reinforcing materials such as steel. Despite the major role of epoxy resins as a bonding material between fibre and substrate, the rapid deterioration of the mechanical properties at elevated temperature is the critical issue for the epoxy matrix. Therefore, substitution of epoxy adhesive with cementitious bonding agent will be beneficial in order to provide more resistant systems at elevated temperatures. Near-surface mounted (NSM) strengthening technique with cement adhesives has only been investigated for torsion. Flexural performance is a significant factor in the strengthening of different structures. This paper reports the experimental study on the behavior of small scale retrofitted beams using Near-Surface Mounted strengthening system with carbon fiber reinforced polymer (CFRP) textile and laminate and cement-base adhesives for flexure. The beams retrofitted with modified cement-based adhesive achieved 98% to 100% ultimate loads of that beams strengthened with epoxy adhesives. Numerical analyses is utilized to evaluate the experimental results, and comparable results were observed between the experimental results and finite element analysis.

Seismic Performance Enhancement of RC Columns Using Thin High-Strength RC Jackets and CFRP Jackets

The existing non-ductile RC structures built prior to the 1960s–1970s were mainly conceived to carry only vertical loads. As a result, the columns of these structures demonstrate poor overall hysteresis behavior during strong earthquakes, dominated by brittle shear or/and premature excessive slipping of the inadequately lap-spliced reinforcement. In the present study, the effectiveness of two different strengthening systems (including either the wrapping of the columns by carbon-fiber-reinforced polymer textile or the use of thin high-strength reinforced concrete jackets), was experimentally and analytically investigated. The main variables examined were the strengthening material, the length of the lap splices and the amount of confinement provided by the jackets. Three cantilever column specimens were constructed without incorporating modern design code requirements for preserving seismic safety and structural integrity. Subsequently, the specimens were strengthened and subjected to earthquake-type loading. Their hysteresis performances were compared, while also evaluated with respect to the response of two similar original specimens and the behavior of a control one with continuous reinforcement, tested in a previous study. The predictions of the proposed analytical formulation for the hysteresis behavior of the strengthened specimens were satisfactorily verified by the experimental results.

Investigation of impact performance of 3-dimensional interlock polymer fabrics in double and multi-angle pass stabbing

This paper presents the influence of fabric structures and stab angles on single-pass stab impact and the repeated and multi-angle stabbings of 3-dimensional (3D) warp interlock structural fabrics based on the high-molecular-weight polyethylene (HMWPE) yarns. Five kinds of samples with different structures were experimentally tested using the drop weight stabbing impact equipment at the same impact energy. Radar charts are plotted to demonstrate the differences among different parameters to a better understanding and a more global characterization of single-pass stabbing impact. An image analysis methodology of Structure From Motion (SFM) is used to compare the fabric deformation in Z direction after the stabbing tests. Results indicated that fabric structures have significant effects on the stab impact property that the orthogonal/through-the-thickness interlock fabric has a good stab impact resistance. Besides, the fabric with stab angle of 90° exhibited better single-pass stab impact property than the counterparts with stab angle of 0°. More importantly, the double-pass stabbing tests are compared to the ones of the single-pass stabbing which shows that a better condition occurs when the stab angles are identical in each pass.

Life-cycle study of concrete bridges strengthened with carbon-fibre-reinforced polymer

China has many bridges in a vulnerable condition, and strengthening is crucial to guarantee their service life and performance. However, environmental impact is rarely considered in the maintenance of reinforced concrete structures. Moreover, considering the effects of vehicle overload and the external environment remains difficult. To solve these problems, the life-cycle reliability and induced environmental impact of strengthening bridges with bonded carbon-fibre-reinforced polymer under different external environmental conditions and overload scenarios were studied using Monte Carlo sampling, first-order second moment and life-cycle assessment methods. A simply supported reinforced concrete T-beam was selected as a case study. The results indicated that the external environmental conditions contributed significantly to the polymer strengthening effect, and polymer plates contributed more to reliability than polymer fabric. In overload scenarios, plates were more suitable for strengthening than fabric. When annual environmental impacts were considered over time, life-cycle maintenance plans with plates were better than with fabric, and environmental impacts were sensitive to the discount rate.

Thermal and mechanical characterization of high performance polymer fabrics for applications in wearable devices

With advances in flexible and wearable device technology, thermal regulation will become increasingly important. Fabrics and substrates used for such applications will be required to effectively spread any heat generated in the devices to ensure user comfort and safety, while also preventing overheating of the electronic components. Commercial fabrics consisting of ultra-high molecular weight polyethylene (UHMW-PE) fibers are currently used in personal body armor and sports gear owing to their high strength, durability, and abrasion resistance. In addition to superior mechanical properties, UHMW-PE fibers exhibit very high axial thermal conductivity due to a high degree of polymer chain orientation. However, these materials have not been widely explored for thermal management applications in flexible and wearable devices. Assessment of their suitability for such applications requires characterization of the thermal and mechanical properties of UHMW-PE in the fabric form that will ultimately be used to construct heat spreading materials. Here, we use advanced techniques to characterize the thermal and mechanical properties of UHMW-PE fabrics, as well as other conventional flexible materials and fabrics. An infrared microscopy-based approach measures the effective in-plane thermal conductivity, while an ASTM-based bend testing method quantifies the bending stiffness. We also characterize the effective thermal behavior of fabrics when subjected to creasing and thermal annealing to assess their reliability for relevant practical engineering applications. Fabrics consisting of UHMW-PE fibers have significantly higher thermal conductivities than the benchmark conventional materials while possessing good mechanical flexibility, thereby showcasing great potential as substrates for flexible and wearable heat spreading application.

Textile Triboelectric Nanogenerators with Diverse 3D-Spacer Fabrics for Improved Output Voltage

Electrically superior triboelectric nanogenerators (TENG) using 3D fabric and PDMS show great application potential for biokinetic energy harvesting and multifunctional self-power devices. In this study, TENG with fabric-PDMS-fabric structure was produced using various 3D fabrics and PDMS. The peak-to-peak output voltage of various 3D fabrics was compared. The output voltage changes due to structure and vertical fibers. Also, the coefficient of surface friction between the PDMS and the fabric improves the output voltage. TENG using different 3D-spacer polymeric fabrics showed different maximum peak-to-peak output voltage performance. It is attributed to the stiffness, lateral elasticity and 3D morphology of the fabrics. It is considered that those factors including stiffness, lateral elasticity and 3D morphology influence the densities in vertical and lateral fiber to fiber interaction.

Fibre-based composites from the integration of metal–organic frameworks and polymers

The integration of metal–organic frameworks (MOFs) with polymer fibres enables the formation of fibrous composite materials with advantages over traditional single-component polymer films and mixed-matrix membranes. In comparison with mixed-matrix membranes, MOF–polymer fibrous composites offer improved molecular transport through the material and easier access to the active sites of MOFs. These attributes make fibrous composites appealing for clothing, personal protective equipment, air purification and filtration, biomedical equipment and delivery of therapeutics, along with detection and sensing applications. In this Review, we outline approaches for the incorporation of MOFs into, or onto, polymer fibres and present some applications for MOF–polymer fabrics. The integration of MOFs and polymers can either occur prior to fibre formation (namely, MOF-first), via particle deposition (resulting in either covalent or non-covalent attachment) of MOFs to the fibre or by in situ MOF growth after fibre formation (namely, fibre-first). We focus on the structure–processing–activity relationships — for example, MOF loading, MOF crystal size, polymer concentration and processing parameters — that impact the behaviour of fibrous composites. We conclude with a discussion of research avenues that can advance this burgeoning field. Composites made from metal–organic frameworks and polymer fibres are gaining popularity in many applications because of their tailorable morphologies and properties. This Review summarizes various methods for fabricating these composites, explores structure–processing–activity relationships and discusses future research opportunities.

Influence of spin finish on degradation, functionalization and long-term storage of polyethylene terephthalate fabrics dedicated to ligament prostheses

Polyethylene terephthalate (PET) fibers and fabrics are widely used for medical device applications such as vascular and anterior cruciate ligament prostheses. Several years ago, we began functionalizing PET fabrics using anionic polymers to enhance their biocompatibility, cell adhesion, proliferation and functional performance as PET ligament prostheses. Polymer functionalization followed a grafting-from process from virgin PET surfaces subject to spin-finish oil additive removal under Soxhlet extraction to remove residual fiber manufacturing oil. Nevertheless, with increasing time from manufacture, PET fabrics stored without a spin finish removal step exhibited degradation of spin finish oil, leading to (1) incomplete surface cleaning, and (2) PET surface degradation. Moreover, oxidizing agents present in the residual degraded oil prevented reliable functionalization of the prosthesis fibers in these PET fabrics. This study compares effects of PET fabric/spin finish oil storage on PET fabric anionic polymer functionalization across two PET fabric ligament storage groups: (1) 2- and 10- year old ligaments, and (2) 26-year old ligaments. Strong interactions between degraded spin finish oil and PET fiber surfaces after long storage times were demonstrated via extraction yield; oil chemistry changed assessed by spectral analysis. Polymer grafting/functionalization efficiency on stored PET fabrics was correlated using atomic force microscopy, including fiber surface roughness and relationships between grafting degree and surface Young’s modulus. New PET fabric Young’s modulus significantly decreased by anionic polymer functionalization (to 96%, grafting degree 1.6 µmol/g) and to reduced modulus and efficiency (29%) for 10 years storage fabric (grafting degree ~ 1 µmol/g). As fiber spin finish is mandatory in biomedically applicable fiber fabrication, assessing effects of spin finish oil on commercial polymer fabrics after longer storage under various conditions (UV light, temperature) is necessary to understand possible impacts on fiber degradation and surface functionalization.

Biodegradable Synthetic Polymers in Textiles – What Lies Beyond PLA and Medical Applications? A Review.

Biodegradable polymers are currently discussed for applications in different fields and are becoming of increasing interest in textile research. While a plethora of work has been done for PLA in medical textiles, other biodegradable polymers and their textile application fields are studied less often, presumably due to higher costs and fewer market opportunities. However, some are emerging from research to pilot scale, and are already utilized commercially in packaging and other sectors but not, unfortunately, in textiles. The commercialisation of such polymers is fuelled by improved biotechnological production processes, show¬ing that textile applications are increasingly conceivable for the future. Additionally, commonly accepted definitions for biodegradability are probably misleading, if they are used to estimate the environmental burden of waste management or recycling of such materials. In this review, the current state of research in the field of biodegradable polymers for the application in textile materials is presented to identify emerging developments for new textile applications. It was clearly seen that PLA is most dominant in that field, while others facilitate new options in the future. The production costs of raw materials and the current patent situation are also evaluated. A special focus is placed on fibre raw materials, coatings, and additives for clothing and technical textiles. Fibre-reinforced composites are excluded, since polymers applied for the matrix component require very different properties compared to the textile materials. This represents a topic to be discussed separately. As a result, these new biodegradable polymers might serve as interesting coating materials for textiles that seem to sneak on to the textile market, as the patent search for such coating formulations suggests. Moreover, new biodegradable fibrous materials for clothing applications can be suggested, but some material properties must be addressed to render them processable on common textile machines.

A hybrid hydrogel/textile composite as flame-resistant dress

Currently, the functional and cost-effective flame-resistant textiles (FRTs) are on high demand. However, such FRTs based on general polymer fabrics are always expensive, readily decompose, and their temperatures quickly rise once exposed to thermal environments. Inspired by the large specific heat of water and high decomposition temperature of inorganic substances like SiO2, this study establishes a simple casting strategy for preparing flame-resistant gel/textiles (FR-GTs). The findings showed that active diffusion of aqueous AAM/SiO2 pre-gel solution into the textile structure enabled the formation of a tough interfacial adhesion between the hydrogel and textiles. The interfacial toughness reached ~272 ​J/m2 because the PAAM/SiO2 nanocomposite hydrogel was filled into textile to form the semi-interpenetrating structure at the interface. The presence of chemical crosslinker (PEGDA) and physical crosslinker (SiO2) limited the volume expansion of the hydrogel upon swelling. In addition, the PAAM/SiO2 nanocomposite hydrogel layer prevented burning in high temperature environments (over 100 ​°C), due to the heat dissipation of water during evaporation. This simple strategy provides a guidance towards the fabrication of hybrid hydrogel/textile composites for the applications like household fire resistant materials such as flame-resistant gloves.

Effects of Technical Textiles and Synthetic Nanofibers on Environmental Pollution.

Textile manufacturing has been one of the highest polluting industrial sectors. It represents about one-fifth of worldwide industrial water pollution. It uses a huge number of chemicals, numerous of which are carcinogenic. The textile industry releases many harmful chemicals, such as heavy metals and formaldehyde, into water streams and soil, as well as toxic gases such as suspended particulate matter and sulphur dioxide to air. These hazardous wastes, may cause diseases and severe problems to human health such as respiratory and heart diseases. Pollution caused by the worldwide textile manufacturing units results in unimaginable harm, such as textile polymers, auxiliaries and dyes, to the environment. This review presents a systematic and comprehensive survey of all recently produced high-performance textiles; and will therefore assist a deeper understanding of technical textiles providing a bridge between manufacturer and end-user. Moreover, the achievements in advanced applications of textile material will be extensively studied. Many classes of technical textiles were proved in a variety of applications of different fields. The introductory material- and process-correlated identifications regarding raw materials and their transformation into yarns, fibers and fabrics followed by dyeing, printing, finishing of technical textiles and their further processing will be explored. Thus, the environmental impacts of technical textiles on soil, air and water are discussed.

Spectral interpretation of deformation processes of polymer textile materials

Spectral interpretation of deformation processes of polymer textile materials

Development of methods for computer analysis of deformation processes of polymer textile materials

Development of methods for computer analysis of deformation processes of polymer textile materials

Mathematical Modeling of Deformation Properties of Polymer Textile Materials from the Position of Spectral Analysis of Viscous Elasticity

Mathematical Modeling of Deformation Properties of Polymer Textile Materials from the Position of Spectral Analysis of Viscous Elasticity

Numerical and Experimental Investigation of the Opposite Influence of Dielectric Anisotropy and Substrate Bending on Planar Radiators and Sensors.

The simultaneous influences of the substrate anisotropy and substrate bending are numerically and experimentally investigated in this paper for planar resonators on flexible textile and polymer substrates. The pure bending effect has been examined by the help of well-selected flexible isotropic substrates. The origin of the anisotropy (direction-depended dielectric constant) of the woven textile fabrics has been numerically and then experimentally verified by two authorship methods described in the paper. The effect of the anisotropy has been numerically divided from the effect of bending and for the first time it was shown that both effects have almost comparable but opposite influences on the resonance characteristics of planar resonators. After the selection of several anisotropic textile fabrics, polymers, and flexible reinforced substrates with measured anisotropy, the opposite influence of both effects, anisotropy and bending, has been experimentally demonstrated for rectangular resonators. The separated impacts of the considered effects are numerically investigated for more sophisticated resonance structures—with different types of slots, with defected grounds and in fractal resonators for the first three fractal iterations. The bending effect is stronger for the slotted structures, while the effect of anisotropy predominates in the fractal structures. Finally, useful conclusions are formulated and the needs for future research are discussed considering effects in metamaterial wearable patches and antennas.

Tensile Behavior of High-Strength, Strain-Hardening Cement-Based Composites (HS-SHCC) Reinforced with Continuous Textile Made of Ultra-High-Molecular-Weight Polyethylene.

The paper at hand presents an investigation of the tensile behavior of high-strength, strain-hardening cement-based composites (HS-SHCC), reinforced with a single layer of continuous, two-dimensional textile made of ultra-high molecular weight polyethylene (UHMWPE). Uniaxial tension tests were performed on the bare UHMWPE textiles, on plain HS-SHCC, and on the hybrid fiber-reinforced composites. The bond properties between the textile yarns and the surrounding composite were investigated in single-yarn pullout experiments. In order to assess the influence of bond strength between the yarn and HS-SHCC on the tensile behavior of the composites with hybrid fiber reinforcement, the textile samples were analyzed both with, and without, an additional coating of epoxy resin and sand. Compared to the composites reinforced with carbon yarns in previous studies by the authors, the high elongation capacity of the UHMWPE textile established the higher strain capacity of the hybrid fiber-reinforced composites, and showed superior energy absorption capacity up to failure. The UHMWPE textile limited the average crack width in comparison with that of plain HS-SHCC, but led to slightly larger crack widths when compared to equivalent composites reinforced with carbon textile, the reason for which was traced back to the lower Young’s modulus and the higher elongation capacity of the polymer textile.

Flame-retardant PNIPAAm/sodium alginate/polyvinyl alcohol hydrogels used for fire-fighting application: Preparation and characteristic evaluations

A novel fire-preventing triple-network (TN) hydrogel was prepared and laminated on cotton fabric to improve fire-resistant performance of cellulose fabric. The TN hydrogel composed of Poly (N-isopropylacrylamide) (PNIPAAm)/sodium alginate (SA)/ Poly (vinyl alcohol) (PVA) exhibited excellent swelling ratio, swelling-deswelling behavior and antibacterial property. Results indicated that introduction of SA could improve water retention capabilities of TN hydrogels. Thermogravimetric experiments showed that the thermal stability of hydrogels was best at a SA: PVA ratio of 2:1. Furthermore, the obtained hydrogel-cotton fabric laminates displayed efficient flame retardancy. Compared to original fabric, hydrogel-fabric laminates were nearly undamaged when exposed to fire for 12 s. This result is attributed to energy absorption as water is heated and evaporates in the hydrogel. The present work provides a new concept to prepare fire-resistant polymer fabric, which may be used in fire-protective clothing to protect the skin from burn injuries.

Comparative Study of Ultraviolet and Infrared Femtosecond Laser Irradiation on Textile Polymers PET and PA66

Comparative Study of Ultraviolet and Infrared Femtosecond Laser Irradiation on Textile Polymers PET and PA66

An experimental approach for strengthening of RC deep beams with web openings using GFRP fabrics and gas actuated fasteners

In this paper, the influences of externally bonded (EB) glass fibre reinforced polymer (GFRP) fabrics and gas actuated fasteners (GAF) on the strengthening of reinforced concrete (RC) deep beams with circular/square web openings of different sizes are investigated experimentally with respect to shear strength, failure mode, load-deflection and stiffness. A total of 19 deep beams having 120 × 420 × 1000 mm size are prepared and tested under two-point loading. One solid deep beam is left un-strengthened, which is considered as the control beam. Out of 18 beams with web openings, six beams, i.e. one beam for each opening size are kept un-strengthened. Other six counterpart beams are strengthened with U-wrapped EB-GFRP fabrics throughout the beam length. In order to improve the bond strength between GFRP fabric sheets and concrete surface, the remaining six counterpart beams are strengthened using both EB-GFRP fabrics and GAF at shear spans only. Test results demonstrate that the presence of web openings in deep beams significantly reduces the shear strength of the beams up to 72% with respect to the solid beam. The beams with web openings strengthened using both the EB-GFRP fabric and GAF are seen to be effective in enhancing the shear strength up to 64% with respect to the counterpart un-strengthened deep beams. Finally, the theoretical shear strength results obtained from the theoretical models available in the previous works are compared with the experimental results for the verification of their accuracy.

Retrofitting of the corroded reinforced concrete columns with CFRP and GFRP fabrics under different corrosion levels

This study aims to evaluate the seismic performance of retrofitted reinforced concrete (RC) columns with glass fibre reinforced polymers (GFRP), and carbon fibre reinforced polymers (CFRP) fabric with different rebar corrosion levels. For this purpose, a total of fifteen square cross-section RC columns with different rebars corrosion ratios were fabricated and tested under the lateral hysteresis and a constant vertical load. A new wrapping technique is employed in order to apply the corrosion, and five different corrosion level of 0%, 5%, 10%, 15% and 20% were obtained. Therefore, the hysteresis performance, energy dissipation, cyclic stiffness, ductility, the maximum bearing capacity and deformation of the specimen were examined. Some models were also developed to predict the ductility and energy absorption of corroded rebars RC columns. The obtained results indicated that the influence of polymer fibre fabrics on the maximum deformation is higher than those with no polymer fabric at low corrosion level (less than 15%) while by raising the corrosion level of rebars, the influence of polymer fibres on the lateral displacement was dropped.