Preparation and flammability properties of hybrid materials containing phosphorous compounds via sol-gel process

Organic-inorganic hybrid coatings containing phosphoric acid (PA) bonded to the organic-inorganic network were prepared from tetraethoxysilane (TEOS) using a sol-gel process. The effect of sol-gel phosphate-based flame retardant coating on polyacrylonitrile fabric properties (flammability, stiffness, and strength) was investigated. Sample characterization of the coated samples were investigated using differential thermal/thermogravimetric analysis (DTA/TGA), Fourier transform infrared spectroscopy (FTIR), X-ray diffractometer (XRD), and scanning electron microscopy (SEM). The results showed that hybrid coating on the polyacrylonitrile fabrics influenced fabric stiffness, strength, and flammability. And also, flammability of the coated samples after washing cycles was investigated, and the flame retardancy properties of the samples after 10 repeated washings were not completely lost.     

Handle,fit and pressure comfort of silk/hybrid yarn woven stretch fabrics

Hybrid yarn was produced by twisting silk with nylon covered lycra yarn. Silk of 20 D in warp and hybrid yarn in weft was woven to develop lustrous woven stretch fabrics for sari blouse. Silk and hybrid yarn fabrics were produced in three different weaves namely plain, crepe and sateen. An in-depth study was carried out to understand the effect of weave on thermal comfort; low stress mechanical properties, total hand value and stretch properties. Nine blouses (3 samples× 3 figures) were constructed from three different woven stretch materials for fit assessment and objective pressure comfort test. The effect of fabric weave, low stress mechanical properties, total hand value and stretch properties on fit and pressure comfort of silk/hybrid yarn stretch fabrics were analyzed. Sateen weave silk/hybrid yarn stretch fabric shows higher total hand value, stretch properties and better thermal comfort properties. Sateen and crepe weave stretch fabrics provided good fit. Sateen weave fabric exerted lower clothing pressure value in the range of 3-12 mmHg at all body locations in standing position and in different postures.     

Correlation between the Thermo-physical Properties and Core Material Structure of Vacuum Insulation Panel: Role of Fiber Types

Vacuum insulation panel (VIP), which is composed of an evacuated core material encapsulated in an envelope and supplemented with a desiccant, is a high performance thermal insulation material. In this paper, thermos-physical properties of chopped fiber, centrifugal-spinneret-blow (CSB) fiber, flame-spinneret-blow (FSB) fiber and hybrid (CSB: FSB=1:1) fiber as fillers of vacuum insulation panel are explored. The results show that the increase of pore size can improve thermal insulation property; fibers distribute in 2-D structure, which can reduce the heat conduction, leads to reduce the thermal conductivity. VIP with chopped fiber has the best thermal insulation, and thermal conductivity is 1.4 mW/m.K. Due to difference of core materials, thermal insulation characteristics of VIP can be divided into three distinct regions based on the internal pressure range, i.e., (I) ≥12000 Pa region, (II) 80-12000 Pa region, (III) ≤ 80 Pa region. It also finds that service life of VIP can be improved by the reducing the pore size of core materials. VIP with different core materials shows different degradation and the degradation rate of VIP with FSB core material is minimum.     

Tensile response and fracture and failure behavior of jute fabrics-flyash-vinylester hybrid composites

In this work, hybrid materials consisting on a vinylester matrix simultaneaously reinforced with jute woven fabrics and flyash particles were prepared. The tensile response and the fracture and failure behavior of these hybrid composites were investigated. Thermal stability of these materials was also studied. The aim was to obtain an environmentally friendly hybrid material with a good balance of tensile and fracture properties at relatively low cost. The effect of a novel treatment for the jute fabrics on the hybrids mechanical and fracture properties was investigated. The best balance of tensile and fracture properties was obtained for the hybrid consisting of fabrics treated with alkali under stress and fly ashes which also exhibited relatively high thermal stability.     

Nylon 66/polyester hybrid cords: 1. Design and investigation of properties

In this study, Nylon 66/Polyester (Ny 66/PET) hybrid cord design and production was investigated to obtain new cord with better performance than conventional cord. The factors affecting cord properties and cord production process were examined. Taguchi design of experiment method was implemented in order to minimize the required number of experiments. Different sets of 4 reference cords conventionally used in tyre industry were prepared and resorcinol-formaldehyde-latex (RFL) treated in order to make a comparison of performance. Mechanical and thermal properties of hybrid cords were measured and compared with the values of reference cords. It was found that the twist level of high modulus PET component in the hybrid cords should be the same or above of the nylon in order to obtain maximum tensile strength. It was observed that shrinkage values of hybrid cords varied between PET and Ny 66 reference cords. Moreover, for all treated hybrid cords, satisfactory cord-rubber adhesion values were obtained by using double dip adhesion system.     

Thermal Insulation Performance of Cotton and PET-based Hybrid Fabrics Impregnated with Silica Aerogel via a Facile Dip-dry Process

We report the morphological features and thermal insulation properties of a series of cotton- and PET-based hybrid fabrics impregnated with silica aerogel. For the purpose, commercially available cotton and PET knitted fabrics were dipped into aqueous dispersions including different silica aerogel contents, dried, and stacked to 1, 3, and 5 layers. The SEM images revealed that the silica aerogel particles were well incorporated into cotton or PET knitted fabrics. The thermal insulating performance of the hybrid fabrics as functions of the silica aerogel content and the number of layers of stacked fabrics were characterized by monitoring the surface temperatures of the fabrics on a plate with a wide temperature range of ~50-80 oC using an infrared camera. The higher thermal insulation performance was attained for both cotton- and PET-based hybrid fabrics with higher silica aerogel contents. In addition, 3-layered hybrid fabrics exhibited noticeably improved thermal insulation performance, compared to 1- or 5-layered fabrics. The thermal insulation property of the cotton-based hybrid fabrics was dominantly influenced by silica aerogel than that of PET-based hybrid fabrics. The overall results demonstrated that the cotton- and PET-based hybrid fabrics with silica aerogel manufactured by a facile dip-dry process could be utilized as protective garments, heat-sensitive devices, pipes, automotive, aircrafts, and buildings for thermal insulation applications.     

Effect of pineapple leaf fibre and kenaf fibre treatment on mechanical performance of phenolic hybrid composites

In this work, hybrid composites were fabricated by hand layup method to hybridize treated Pineapple leaf fibre (PALF) and kenaf fibre (KF) in order to achieve superior mechanical properties on untreated hybrid composites. Silane treated PALF/KF phenolic hybrid composites were prepared on various fibre fraction to investigate mechanical properties and compared with untreated PALF/KF phenolic hybrid composites. The effects of silane treatment on hybrid composites were investigated by fourier transform infrared spectroscopy (FTIR) and found very effective peaks. Effects of treated hybrid composites were morphologically investigated by using scanning electron microscopy images and analysed the tensile results. Treated PALF/KF phenolic hybrid composites enhanced the flexural strength, modulus, impact strength and energy absorption while tensile strength and modulus decreased. The overall performances of 70 % PALF 30 % Kenaf hybrid composites were improved after silane treatment. Silane treatment of fibres improved the mechanical performance of hybrid composites and it can be utilized to produce components for building structure, materials and automobile applications.     

Enhanced mechanical and thermal properties of hybrid graphene nanoplatelets/multiwall carbon nanotubes reinforced polyethylene terephthalate nanocomposites

The effects of graphene nanoplatelets (GNP) and multiwall carbon nanotube (MWCNT) hybrid nanofillers on the mechanical and thermal properties of reinforced polyethylene terephthalate (PET) have been investigated. The nanocomposites were melt blended using the counter rotating twin screw extruder followed by injection molding. Their morphology, mechanical and thermal properties were characterized. Combination of the two nanofillers in composites formulation supplemented each other which resulted in the overall improvement in adhesion between fillers and matrix. The mechanical properties and thermal stability of the hybrid nanocomposites (PET/GNP1.5/MWCNT1.5) were significantly improved compared to PET/GNP3 and PET/MWCNT3 single filer nanocomposites. However, it was observed that GNP was better in improving the mechanical properties but MWCNT resulted in higher thermal stability of Nanocomposite. The transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM) revealed uniform dispersion of the hybrid fillers in PET/GNP1.5/MWCNT1.5 nanocomposites while agglomeration was observed at higher filler content. The MWCNT prevented the phenomenal stacking of the GNPs by forming a bridge between adjacent GNP planes resulting in higher dispersion of fillers. This complimentary geometrical structure is responsible for the significant improvement in the thermal stability and mechanical properties of the hybrid nanocomposites.     

Study of moisture and thermal transfer properties as a function of the fiber material variation

The properties of moisture transfer and the comfort of mesh-structured fabrics with various knit compositions and properties were investigated. The comfort effects of the double knitted fabrics combined with different cross-shaped fibers composed of dyeable-polypropylene (PPd) and regular polyester (PET) double-knitted fabrics were studied. A series of PET, PPd, Coolmax^® (Cm) with single knitted fabrics and PPd/Cm with double knitted fabrics were evaluated to determine the physical properties and wearing performance for comfortable clothing. To compare the structural properties involving the vapor transfer of 4 types of fabrics with different fiber compositions, fiber types, weights, and thicknesses, the surface structure and pore characteristics were evaluated by scanning electron microscopy and a capillary flow porometer. The properties of moisture transfer were tested using vertical wicking and gravimetric absorbent testing system (GATS). In addition, the comfort performance measured by the thermal insulation value (Rt) and moisture permeability index (im) with a thermal manikin in a conditioned walk-in environmental test chamber was predicted. The result showed that the PPd/Cm sample has potential applications as good comfort fabric materials.     

Characteristics of double-layer coated fabrics with and without phase change materials and nano-particles

Stability in a low temperature environment is needed for a textile to be used as winter wear. This research was presented the characteristics of fabrics by double-thin-layered coating with and without phase change materials (PCM) and several nano-sized inorganic particles (N-particles). Silica, Ag, Zr, and carbon types of N-particles were used for investigating the N-particles effect. For the experimental method, the PCM and N-particles were coated consecutively in the wet and dry coating process, respectively. The N-particles on the surface of the coated fabrics were confirmed by energy dispersive spectroscopy (EDS), and after double-layer composite coating, the adhesion durability, water vapor permeability, water penetration resistance, DSC, thermographic photography, far infrared (FIR) emission effect, and the thermal insulation of the coated fabrics were tested for investigating the performances. Their compatibility and adhesion were superior when the add-on of N-particles was 10 %. From the DSC reproducibility results, we verified that the N-particles coated fabric preserved its thermal stability by absorbing latent heat. On the other hand, the FIR emission rate and energy of the Ag N-particle based sample were not better than the control sample.     

Water repellency and warmth retention finishes for polyester fabrics based on hybrid materials comprising zirconia,silica, and thiazole dyes prepared via sol-gel synthesis

A series of hybrid materials composed of zirconia, silica, and thiazole dyes were synthesized from zirconium npropoxide (ZNP) and tetraethoxysilane (TEOS) using heteroaryl 2-amino-thiazole azo dyes, and prepared via the sol-gel process. The heterocyclic 2-amino-thiazole azo dyes underwent a hydrolysis-condensation reaction with an appropriate proportion of ZNP under a catalyst, using a constant ratio of vinyltriethoxysilane (VTES) and TEOS. The structures of these hybrid materials composed of zirconia/silica/thiazole dyes were characterized using Fourier transform infrared (FT-IR) analysis. The surface morphologies of the polyethylene terephthalate (PET) fabrics were evaluated using scanning electron microscopy (SEM). The SEM images demonstrated the uniform dyeing of the PET fabrics, which confirmed the reaction of the hybrid materials with the PET fabrics. The water contact angle, washing fastness, color uniformity, and warmth retention of the PET fabrics dyed with the hybrid materials composed of the zirconia/silica/thiazole dyes were evaluated. The evaluation results indicated that these fabrics offered enhanced warmth retention properties and good water repellency.     

Study on mechanical and thermal properties of fiber-reinforced Epoxy/Hybrid-silica composite

Recently, carbon fiber composites have been widely used as structural reinforcement materials of buildings, replacing reinforcing bars or concrete. And the increase in use of super fibers such as aramid and high strength PE, which is aimed at improving the reinforcement properties, has resulted in a demand for a resin system with excellent mechanical and thermal properties. In this research, a fiber-reinforced composite has been produced by using the super fibers such as carbon fiber or aramid fiber, reinforcement resin and the silica hybrid compound containing epoxy group. This study was carried out to confirm the effect of the silica hybrid on mechanical properties, heat resistance and adhesion strength of a fiber-reinforced epoxy composite, which was produced by blending silica or introducing silica hybrid through covalent bonds. And the silica hybrid containing epoxy group, which may be introduced to the structure of fiber-reinforced epoxy composite through covalent bonds caused by reaction with a hardener, has been used, so that the heat resistance and adhesion strength could be improved.     

Surface properties studies of MPCMs containing fabrics for thermo-regulating textiles

This paper reports the effect of microencapsulated phase change materials (MPCMs) and silicon carbide (SiC) by a direct composite coating on outdoor winter fabrics by examining the changes in the mechanical and physical properties that occur before and after the composite coating. Pretreated waterproof breathable nylon was coated with PCMs 20 wt% (20PCM) and PCMs 20 wt%/SiC 20 wt% (SC-20PCM). The far-infrared (FIR) emissivity was measured using a Fourier transform infrared spectroradiometer. The cross-section morphology, mechanical properties and changes in pore size were examined by scanning electron microscopy (SEM), a Kawabata evaluation system for fabrics (KES-F) and porometry, respectively. SEM revealed the successful embedding of MPCMs and SiC into the coating layer. The KES-F system showed that the application of coating additives onto the fabrics made them stiffer and slightly heavier but decreased their pore size. The FIR emissivity was only marginally improved from 0.88 to 0.9.     

Synthesis and flame-retardancy of UV-curable methacryloyloxy ethyl phosphates

Tris[2-methacryloyloxy ethyl] phosphate (TMEP), bis(2-methacryloyloxy) ethyl phosphate (DMEP), and 2-(methacryloyloxy ethyl) phosphate (MMEP) were synthesized from phosphorous oxychloride and 2-hydroxyethyl methacrylate, which can be used as flame retardant monomers for UV-curable coating systems. The characterization of the synthesized monomers was carried out by ¹H-NMR, FT-IR, thermo-gravimetric analysis, and the limited oxygen index (LOI) test. The thermal behavior of the cured films depended on phosphorous content and the methacrylate groups in the monomer. The UVcured films from TMEP, DMEP, and MMEP monomers showed LOIS of 28.5, 30.3, and 35.1 respectively. Also, LOI up to 25.4 was obtained for the UV-coated cotton fabrics, which presumably occur through a condensed phase mechanism as verified in the increased residue number. The higher performance of UV-coated cotton fabrics compared to PET was attributed to the facile dehydration and crosslinking of the cellulosic materials.     

Protective performance of thermal protective clothing assemblies exposed to different radiant heat fluxes

Three layered clothing assemblies were constructed from commercial heat protective textile clothing materials for outer, middle and inner layers. Thermal liners, used as middle layer, were prepared from Nomex fibres of two different fineness keeping other parameters constant. Different three layered combinations of fabrics were compared for radiant heat protective performance based on the estimate of burn injury time using Stoll’s curve. Analysis of experimental results showed that characteristics of the outer layer fabric and its interaction with applied heat flux are important factors that affect thermal response of the clothing assemblies. Fineness of the constituent fibres of nonwoven thermal liner was found to significantly affect the protective performance. Thermal properties, porosity, optical properties of the clothing layers found to affect heat protection provided by clothing assembly.     

Transport properties of layered fabric systems based on electrospun nanofibers

Layered fabric systems with electrospun polyurethane fiber web layered on spunbonded nonwoven were developed to examine the feasibility of developing protective textile materials as barriers to liquid penetration using electrospinning. Barrier performance was evaluated for layered fabric systems, using pesticide mixtures that represent a range of surface tension and viscosity. Air permeability and water vapor transmission were assessed as indications of thermal comfort performance. Protection performance and air/moisture vapor transport properties were compared for layered fabric systems and existing materials for personal protective equipment (PPE). Layered fabric systems with electrospun nanofiber web showed barrier performance in the range between microporous materials and nonwovens used for protective clothing. Layered fabric structures with the web area density of 1.0 and 2.0 g/m² exhibited air permeability higher than most PPE materials currently in use; moisture vapor transport was in a range comparable to nonwovens and typical woven work clothing fabrics. Comparisons of layered fabric systems and currently available PPE materials indicate that barrier/transport properties that may not be attainable with existing PPE materials could be achieved from layered fabric systems with electrospun nanofibrous web.     

Plasma-assisted surface modification of polyester fabric for developing halochromic properties

In the field of textiles, introducing pH-sensitive dyes onto fibrous materials is a promising approach for the development of flexible sensor. In this study, poly(ethylene terephthalate) (PET) textile surface with halochromic properties was fabricated by plasma-assisted sol-gel coating, followed by immobilization of two different azo pH-indicator dyes; namely Brilliant yellow and Congo red by conventional printing technique of fabrics. 3-aminopropyltriethoxysilane (APTES) was used as a coupling agent for attaching the pH-sensitive dyes through its terminal amines. The surface immobilization of APTES on PET fabric was conducted by the pad-dry-cure method. Moreover, the influence of oxygen plasma pre-treatment and the method of post-treatment either by oxygen plasma or by thermal treatment on the stability of sol-gel based matrix was investigated. The morphology and chemistry of 3-aminopropyltriethoxysilane coated PET surfaces were examined by using surface sensitive methods including electrokinetic and time-dependent contact angle measurements as well as X-ray photoelectron spectroscopy (XPS). In addition, fastness tests of the printed fabrics and color strength were carried out to assess the effectiveness of the fabric surface modification. Results indicate that sol-gel matrix exhibited a more stability by thermal post-treatment at 150 C for 5 min. Also, the results revealed that the printed fabrics with halochromic properties demonstrated sufficient stability against leaching by washing. The current work opens up a novel opportunity to develop flexible sensors based on fibrous materials, which have the potential to be employed in variable industrial applications.     

Anodic TiO₂ nanotube layers electrochemically filled with MoO₃ and their antimicrobial properties

In the present work, the authors produce a Ti surface with a TiO? nanotube coating and investigate the electrochemical filling of these layers with MoO?. The authors demonstrate that using a potential cycling technique, a homogenous MoO? coating can be generated. Controllable and variable coating thicknesses are achieved by a variation of the number of cycles. Thicknesses from a few nanometers to complete filling of the nanotube layers can be obtained. A thermal treatment is used to convert the as-deposited amorphous MoO(x) phases into MoO?. These MoO? loaded nanotube layers were then investigated regarding their antimicrobial properties using strains of Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. The authors found that the combination of crystalline MoO? on TiO? nanotubes shows excellent antimicrobial properties.     

Mechanical and moisture absorption characterization of PLA composites reinforced with nano-coated flax fibers

This research is intended to improve the interface between the fibers and the matrix and limit water absorption of bio-based material thereby decreasing degradation of the composites when they are exposed to external environment such as high temperature and humidity. In this study, flax fibers were treated with an organic surface coating containing SiO₂ nanoparticles. This coating was a dispersion of silica fume in epoxy. One composite was also made with raw fibers as reference as well as one sample of pure PLA. Flax fibers/PLA composites were manufactured by hot pressing by stacking 4 PLA films and 3 pieces of flax fabric. Morphology and dispersion of the coating on the fibers was observed by scanning electron microscopy (SEM), small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM). Accelerated ageing was carried out on the 3 materials by placing them in a 50 °C water bath until saturation to investigate the influence of the coating on water diffusion. Mechanical properties of the different composites were investigated by tensile (before and after conditioning) and short beam shear (SBS) testing in order to evaluate the impact of the coating on the interfacial properties of the materials. The results show that the fibers surface was homogenized and that a better adhesion was reached because of the coating. Coating the fibers also allowed the decrease in water uptake by more than 10 % and their protection during conditioning, preserving their mechanical properties.     

Effect of kenaf and EFB fiber hybridization on physical and thermo-mechanical properties of PLA biocomposites

Kenaf/empty fruit bunch/polylactic acid (kenaf/EFB/PLA) hybrid biocomposites were prepared using hot press technique. The ratio of fiber to polylactic acid was set at 60:40 with 1:1 ratio between kenaf and empty fruit bunch fibers. Physical, mechanical and thermal properties of hybrid biocomposites were subsequently characterized using Fourier transform infrared spectroscopy, scanning electron microscope, X-ray diffraction, thermogravimetric analysis, differential scanning calorimetry, tensile and water absorption tests. Test results indicated that mechanically stronger fiber was able to support the weaker fiber. Hybrid fiber biocomposite had higher crystallinity as compared to single fiber biocomposite. Water absorption of hybrid composite was higher as compared to single fiber composite. Thermal result revealed that hybridization of fiber was not significantly influence the thermal properties of composites. However, the presence of two different fibers proposed good wettability properties, which could reduce the formation of voids at the fibers-polymer interface and produce composites with high stiffness and strength.