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More than 50% of the flame retardants used in the polymer and plastic industries are metal hydroxides. Among them, aluminum trihydroxide (ATH) is the most widely used due to its low toxicity and corrosiveness and its cost-effectiveness. The use of high-volume ATH in polymers reduces the mechanical properties. In this work, clay nanoparticles were added into epoxy/glass fiber/ATH hybrid composites to improve the mechanical and thermal properties of the composites. The effect of nano-clay content (1, 3, and 5 phr) on mechanical properties such as tensile and flexural strength and modulus, and thermal properties was investigated. Thermal properties were evaluated by Differential Scanning Calorimetry (DSC), and Thermogravimetric Analysis (TGA). The result of mechanical tests showed that adding 3 phr of clay nanoparticles increases tensile and flexural strength by 10% and 9.2%, respectively. The flammability of the composites was measured in horizontal mode. The flammability results revealed that introducing 3 phr of nano-clay improves the flammability of the composites by 41%. [ABSTRACT FROM AUTHOR]

In this study, De Gennes's scaling theory was developed to evaluate the variation of distance-dependent thermal properties inside the polymer/particle interphase region based on the molecular characteristics of the polymer matrix and surface adsorption energy. Accordingly, the average thermal conduction coefficient of the region was predicted and used to approximate the overall thermal conductivity of the nanocomposite system. The physical characteristics of the nanoparticle clusters (e.g., size and content) were defined using a specific strategy based on the equilibrium between dispersion and cohesion energies during the preparation of the nanocomposite samples, via melt mixing. Maxwell's model was also developed and used to predict the thermal conduction coefficient of the polymer/nanoparticle system considering the determinative impact of the polymer/particle interphase region and aggregation/agglomeration phenomenon. It was found that the scaling parameter, defining the polymer/particle interaction strength, increased by almost 50% by increasing the compatibility. This also increased the thermal conductivity of the interphase from 1.401 (W.m-1.K-1) to 3.028 (W.m-1.K-1) in the samples containing compatible nanoparticles. The thermal conductivity of nanoparticle clusters decreased exponentially with increasing the number of involved nanoparticles. The maximum prediction error of the proposed model (6.9%) was 12% less than that of the original Maxwell's model. [ABSTRACT FROM AUTHOR]

A fabric touch tester is a novel instrument with fabric handling properties. Its principal advantage is that the device has integrated modules for compression, surface friction, and thermal and bending properties. This module integration simplifies the testing process, and provides an efficient measurement method, and a comprehensive physical index. This study focused on woven fabrics for dress shirts. The fabric samples comprised three groups with various yarn compositions – that is, cotton, polyester, and wool. Sample group 1 was composed of cotton, polyester, and blended yarns; sample group 2 mainly compared the effect of twist yarns on the fabric touch; and sample group 3 was composed of wool and blended yarns with polyester. The handling properties were assessed by compression work and the compression recovery rate for the compression attributes. The results revealed that fabric (T100p1) with high twist-level yarns had a higher value of compression work (242.56 gf*mm2), and the texture type may affect the compression characteristics more significantly than the blending ratio. The fabric touch tester can also distinguish small changes in the compression properties of samples (0.43–0.71), the maximum heat flux and surface roughness amplitude for the thermal and surface roughness properties. The results revealed that the maximum heat flux value of all the samples in this study was 1109 Wm−2, the sample C100 using pure cotton yarn had the highest maximum heat flux value (1270 Wm−2). Moreover, the sample W100 with 100% wool fiber yarn had the highest surface roughness amplitude in the warp direction (81 μm) and surface roughness amplitude in the weft direction (67 μm). Finally, the bending average rigidity was used to assess the bending performance of the fabric samples. These fabric touch tester indicators were applied to analyze the fabric handling characteristics of woven shirting fabrics, and perform cross-analysis among samples. [ABSTRACT FROM AUTHOR]

Composites synthesized from natural waste and recycled plastic is quite a promising and interesting field for scientists and polymer industries. In the present study, bio-composites based on agriculture residue Sesamum indicum L. and recycled-low density polyethylene were synthesized by extrusion and injection molding technique at a fiber loading of 10–40 wt%. Additionally, 3% of maleic anhydride grafted low density polyethylene was used as a compatibilizer. The prepared composites were irradiated at 25 kGy, 75 kGy and 125 kGy doses of gamma rays. The effects of different fiber content and gamma doses on mechanical properties were studied statistically by Design Expert software. Response surface methodology was employed to depict the interaction among various factors and optimization was done by desirability index method. Findings indicated that composites having 30% Sesamum indicum L. irradiated at 125 kGy demonstrated best mechanical properties. A significant enhancement in tensile and flexural properties of irradiated composites can be explained effectively in terms of the cross-linking effect. The fiber–matrix adhesion and modifications in composite structure was characterized by fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), and X-Ray diffraction (XRD) analysis. Furthermore, thermal stability of the composites was also found to be increased. In addition, gamma-irradiated composite exhibited the highest storage modulus and a decrease in mechanical loss factor was also observed. [ABSTRACT FROM AUTHOR]

In this study, the thermos-mechanical characteristics of bamboo fiber-reinforced epoxy polymer composites made by compression molding and hand lay-up techniques are discussed. A lab-scale compression molding machine was fabricated for this purpose using the scrap materials of the Central workshop of Tezpur University, India. To find the suitable NaOH concentration for bamboo fiber strip treatment, bamboo strips were treated with 5, 8, 12, and 15 wt.% NaOH solutions for 12 h in each sample. It is determined that 12 wt.% NaOH treated bamboo strips were optimal for the fabrication of composites by single fiber tensile test, single fiber pull-out test, scanning electron microscopy (SEM), and Fourier transforms infrared spectroscopy (FTIR). Alkali treatment improved the interfacial strength with epoxy resin. It is seen that 8, 12, and 15 wt.% NaOH treated bamboo fiber strips become more compatible with the resin. The investigation explored the effects of mechanical and thermal characteristics of composites fabricated by the two different fabrication techniques. The thermal behavior of composites was investigated using thermogravimetric analysis (TGA). The Mechanical properties of composites produced by compression molding machine are found to be better than the hand lay-up method. [ABSTRACT FROM AUTHOR]

In this paper, hydrophilic cotton (CO) yarn and hydrophobic cross-section polyester (PET) filaments were used to prepare single-layer interwoven fabrics (CO/PET fabrics) with plain, 3/1 twill, and 8/5 satin to formulate a hydrophobicity–hydrophilicity gradient across the fabric for obtaining a good water transfer ability. The CO fabrics and PET fabrics were prepared for comparison. The contact angle and thermo-physiology properties of the fabrics, including the wicking property, moisture management ability, drying property, air permeability and water vapor permeability, thermal property, and dynamic cooling property, were investigated. The results show that the asymmetric hydrophobicity–hydrophilicity characteristic can be formed across CO/PET fabric with 3/1 twill and 8/5 satin. This can improve the water transfer ability from the inside to the outside of the fabrics, and the longer the floating length of the fabric is, the stronger the water transfer ability is. These two fabrics also exhibit excellent wicking properties, overall moisture management capability, and thermal comfort, and have good permeability, drying properties, and dynamic cooling properties compared to the corresponding fabrics. As a result, these two CO/PET interwoven textiles are more suitable for application as clothes worn in summer. The interweaving technique combining hydrophilic and hydrophobic yarns is an easy and cost-effective method to prepare fabrics that meet summer requirements. This work provides insight into the thermal and moisture comfort property of interwoven fabrics for summer garments. [ABSTRACT FROM AUTHOR]

Textiles are essential for providing thermal and wet comfort for people as well as aesthetic pleasure since they act as the interface between the human body and the environment. Maintaining thermal comfort is crucial for effective human body energy management in cold weather. It is essential to develop winter fabrics that effectively integrate hygroscopic heat generation and moisture management technologies to keep skin warm and dry for the wearer. In this study, we fabricated bilayer and trilayer woven fabrics with hygroscopic exothermic properties and moisture management performance based on the optimization design of gradient wettability and functional fiber materials. The air permeability, moisture management characteristics, thermal physiological properties, and hygroscopic heat generation performances of the developed fabric were investigated from the perspective of yarn composition and structure. These fabrics were demonstrated to achieve efficient water transport and durative and evenly distributed hygroscopic exothermic properties to avoid the cold moist feeling after sweat. We anticipate that the fabric strategy used in this work can provide valuable structural superiority and performance enhancement for smart thermal and wet comfort textiles. [ABSTRACT FROM AUTHOR]

The vacuum bagging is a common but critical step of various manufacturing process chains for Carbon/Glass Fibre reinforced polymers (C/GFRP). Whilst developing a new generation of vacuum bagging, significant efforts have been made to deeply understand the relevant physics fields, process variables involved and to provide predictive approaches to support dimensioning and scaling exercises prior to implementation into real production process. Main features of the new bagging system are, (1) the reduction of material diversity through merging of various properties within one single layer and, (2) the suppression of critical folding steps by using thermoforming for pre-shaping purposes. This paper will mainly focus on considerations of heat transfer during the pre-shaping of the film, directly on the CFRP part short before the curing step. For the better risk assessment of the short time exposition of an uncured composite part to the heat flow, a problem of transient coupled field analysis involving heat transfer via conduction, convection and radiation is formulated and solved by using Finite Element Analysis in COMSOL under consideration of realistic process conditions. Further a section dedicated to the comparison of the obtained results with measurements performed on a system including an IR-emitter, the bagging material, a ground plate and in some studies as well a CFRP sample is included. During the study the influence of time, power output of the emitter, distance between emitter and surface as well as irradiation angle has been assessed including a comparison of simulated results and performed measurements. [ABSTRACT FROM AUTHOR]

In this study, the effect of fiber orientation on the temperature history during the layup process is comprehensively investigated experimentally and numerically. Specimens with three different fiber orientations (i.e. [0°/0°/0°], [0°/45°/0°], and [0°/90°/0°]) are manufactured at two layup speeds and characterized for determining the degree of intimate contact and then calculating the thermal contact resistance. Then, an improved thermal model with thermal contact resistance is developed and validated to predict the temperature history accurately. The experimental results indicate that the degree of intimate contact decreases by increasing the difference in fiber orientation between the interfaces of successive plies, revealing a relationship between substrate fiber orientations and cooling rates. The effect of cooling rate on the degree of crystallinity is studied for all stacking configurations at two layup speeds and found that as the angle between the subsequent plies decreases, the cooling increases, leading to a drop in the degree of crystallinity. The outcomes of this study address the need for an improved thermal model approach for accurately predicting the thermal history of the manufactured composite by the laser-assisted fiber placement process. [ABSTRACT FROM AUTHOR]

Resin mineral composite (RMC), composed of granite aggregate, fly ash, epoxy resin, etc., has been widely noticed in the field of ultra-precision machining by its excellent vibration damping performance. However, RMC's application is limited by its low mechanical strength. In this paper, two aggregate gradation schemes, containing fractal aggregate gradation (FAG) and coarse aggregate broken gradation (CABG), are designed before researching the effects of aggregate gradation schemes, maximum aggregate size, resin dosage, vibration time, and defoaming agent dosage on the mechanical properties, porosity, and coefficient of thermal expansion (CTE) of the RMC. Shown by the experimental results, CABG has a better performance than FAG both on their mechanical properties, porosity, and thermal expansion properties. FAG and CABG's compressive strength and elastic modulus reach their maximum values at the resin dosages of 10 wt% and 9 wt%, respectively. Their optimal vibration times are 40 min and 30 min, and optimal defoaming agent dosages are 1.5 wt% and 1.0 wt%, respectively. With the optimal preparation process, 100°C RMC's compressive strength and elastic modulus increase by 23.8% and 8.6%, respectively, and its CTE decreases by 58.4%. By this research, the resin dosage, vibration time, and RMC's manufacturing cost would be effectively reduced, thus improving RMC's application in ultra-precision machine tools. [ABSTRACT FROM AUTHOR]

This study investigated the thermal, mechanical, and oil absorption-retention properties at various temperatures (20°C, 30°C, 40°C, 50°C, and 60°C) of three-dimensional (3D) weft-knitted spacer fabrics with optimal performance of silica aerogel coating that demands exceptional attention. Silica aerogels and (silica aerogels + poly(vinyl-alcohol)) sols were prepared and coated on 3D weft-knitted spacer fabrics to study and compare the basic properties, i.e. thermal resistance, thermal conductivity, tensile strength, initial modulus, compression, bending rigidity, wettability, oil absorption, and retention capacity. The scanning electron microscopy and Fourier transform infrared spectroscopy studies were completed to understand the influence of both coatings on 3D weft-knitted spacer fabrics such as surface morphology and molecular interaction. The tensile, bending, and compression tests of 3D weft-knitted spacer fabrics were accomplished to check their durability, bendability, and compressibility. All the coated samples (both silica aerogels and (silica aerogels + poly(vinyl-alcohol))) showed greater thermal resistance (0.0971 ± 0.0003 m2 KW−1 and 0.0912 ± 0.0005 m2 KW−1) and lower thermal conductivity (0.0309 ± 0.0001 Wm−1 K−1 and 0.0329 ± 0.0002 Wm−1 K−1) with better thermal stability than the uncoated samples, most specifically coated sample 5. Besides, coated sample 5 exposed higher oil absorption ((7.91 ± 0.06 g/g and 7.88 ± 0.06 g/g) and (7.56 ± 0.04 g/g and 7.53 ± 0.04 g/g)) and retention ((90.10 ± 0.53% and 89.07 ± 0.55%) and (92.47 ± 0.49% and 91.43 ± 0.47%)) capacity for vegetable and engine oil in all conditions, especially at 40°C. The outcomes demonstrated that both coatings played a vital role in the thermal, mechanical, and wettability properties of 3D weft-knitted spacer fabrics with statistically significant performance (p < 0.05). Moreover, these new types of sorbents (3D weft-knitted spacer fabrics) have better consequences in most cases than conventional knitted, woven, and nonwoven sorbents. Hence, these 3D weft-knitted spacer fabrics could be used for industrial applications as eco-friendly and multifunctional oil sorbent materials. [ABSTRACT FROM AUTHOR]

Hybrid polymer composites are utilized in biomechanical design and orthopedic surgery training to imitate the thermomechanical behavior of human bones. Despite extensive research on the mechanics of hybrid composites in biomechanical design, information on their thermomechanical response during orthopedic drilling operations is scarce. This paper presents a new experimental study to characterize the force and temperature generated during the drilling of hybrid composites that simulate human bones. To simulate the hybrid multi-layer structure of bones, the studied composite comprises a Polyurethane core sandwiched between Glass-Fiber Reinforced Polymer (GFRP) layers—the former resembling the cancellous part of the bone and the latter cortical layers. This study also identifies an empirical relationship between thrust force, temperature, drilling feed and speed, and composite composition. Empirical models are developed using multivariate polynomial regression (MPR) and artificial neural network (ANN) to predict the force and temperature during drilling. The models have a correlation coefficient of above 0.9 between predicted and measured results and can be used to improve orthopedic drilling design and control. [ABSTRACT FROM AUTHOR]

Poly(p-phenylene benzobisoxazole) fiber is a kind of rigid-rod polymer fiber and has a fibrillar structure. It can be fibrillated through a refining process. In this study, the highly fibrillated poly(p-phenylene benzobisoxazole) fiber, which consists of poly(p-phenylene benzobisoxazole) fibrils, was prepared by refining and fractionalizing. It was found that the poly(p-phenylene benzobisoxazole) fibril has a specific surface area of 41.5 m2/g, and the diameter can be tens of nanometers. Poly(p-phenylene benzobisoxazole) fibrils can be prepared into the paper by a wet-laid formation process. It was found that the average pore size of poly(p-phenylene benzobisoxazole) paper was 0.64 μm. The filtration efficiency of poly(p-phenylene benzobisoxazole) paper was 99.96% for particles with a size of 150 nm. After being heated at 400°C for 5 min, the poly(p-phenylene benzobisoxazole) paper could still retain a complete structure and have a filtration efficiency of 99.58%. It is suggested that poly(p-phenylene benzobisoxazole) paper has a potential application in high-efficiency particulate air filters used in air and gas treatment systems in some industrial facilities to resist heated air with a temperature of 400°C. [ABSTRACT FROM AUTHOR]

Carbon fibers composites performance strengthening through graft Carbon nanotubes is a research hotspot at present. Here, a method for rapidly and effectively dispersing and removing CNT aggregates during spraying the CNTs onto CFs surface by the three-stage channel is reported. The scanning electron microscopy image characterization results shows that the three-stage channel has a significant effect on the removal of CNTs aggregates, and the obtained p-CNTs has a good dispersion morphology. Under the same condition, p-CNTs@CFs/EP and CNTs@CFs/EP composites are prepared by the three-stage channel spraying and direct spraying method respectively. Compared with no treatment CFs composites (o@CFs/EP), the tensile, compressive and interlaminar shear strength and radial thermal conductivity (λ⊥) of the CNTs@CFs/EP are increased by 7%, 11%, 9% and 80% (2452.04 MPa, 1209.37 MPa, 89.30 MPa and 1.28 W/(m·K)), the p-CNTs@CFs/EP increased by 29%, 35%, 37% and 203% (2949.06 MPa, 1471.67 MPa, 112.37 MPa and 2.15 W/(m·K)), the CNTs@CFs/EP resistivity is 72.72 Ω·m, a 64% decrease, the p-CNTs@CFs/EP is 45.45 Ω·m, a decrease of 78%. This indicates that the CFs composites prepared by the three-stage channel spraying method has better performance than direct spraying and no treatment. This method provides a new idea for CFs composites performance strengthening. [ABSTRACT FROM AUTHOR]

Valorization of wheat straw fiber/recycled polypropylene nanocomposites was investigated through studying the individual and combined effects of organically modified montmorillonite (OMMT) and alkali treatments on the given composites. FTIR spectra indicated the reduction of wheat straw fibers' hydroxyl groups due to hemicellulose removal resulting from alkali treatment. There were also trace diminutions in C-O peak intensities due to the degradation of little amounts of lignin. X-ray analysis revealed the intercalation of nanoclay in the polymer matrix. The improved interaction of fiber-polymer interfaces brought about by alkali treatment was also confirmed by scanning electron microscopy. The water absorption and thickness swelling properties of the nanocomposites were improved due to the barrier properties of nanoclay against water ingress. The flexural strength and modulus of elasticity increased by the individual, and likewise combined treatments. Thermogravimetric analysis demonstrated that the temperatures of first and second stages of composites' thermal degradation increased via the formation of a carbonized char layer thermally insulating the deeper composite layers. Differential scanning calorimetry showed some slight increases in the melting temperature, melting enthalpy, crystallisation temperature, crystallisation enthalpy, and crystallinity index of the treated composites due to the nucleating effect of nanofillers. The overall results showed that the combined treatment of OMMT and NaOH (vs. the individual ones) could significantly improve the overall properties of the studied composites. This was due to some interesting synergistic effects of the given treatments converting the wheat straw fiber/recycled polypropylene nanocomposites to high performance materials of choice for industry. [ABSTRACT FROM AUTHOR]

Research and development on natural fibre-reinforced composites (NFRCs) is constantly increasing and their use is expanding into new areas of applications. One of the main problems is the absorption of humidity due to the hydrophilic characteristic of the natural fibre, which leads to low interfacial adhesion between the fibre and the hydrophobic matrix and consequently, relatively low mechanical properties. One method to reduce the sensitivity of mechanical and thermal properties of NFRCs to water uptake is the hybridization by using synthetic fibres and/or fillers. This research investigates the effect of ageing on the mechanical and thermal properties of different natural fibre and hybrid composites. Pure jute, pure jute modified with two different types of fillers (micro glass and nano TiO2) and interlaminar hybrid jute/glass fibre-reinforced polymer composites were fabricated. Bulk specimens were used to measure the diffusion coefficient of water in the composites, and tensile and flexural specimens were used to measure the mechanical properties of the conditioned specimens. A thermogravimetric technique (TGA) analysis was used to measure and compare the degradation temperature of all composites studied as a function of ageing. Finally, a scanning electron microscopy (SEM) analysis was performed to examine the fracture surfaces of the specimens tested. It was found that the water uptake decreases by adding the synthetic fibres and the fillers to the NFRCs. The mechanical properties of the composites (the tensile and flexural strength and modulus) tend to decrease with the increase of water content, and they are partially recovered after desorption at the same temperature as the absorption. The thermal properties of natural fibre composites are affected by water absorption and by the hybridization. The hybridization of the composites increased the maximum degradation temperature when compared to the pure jute, while the addition of fillers improved the thermal properties of aged specimens (the initial degradation temperature values were higher than those for the pure jute composites). [ABSTRACT FROM AUTHOR]

The compression and insulation properties of down are crucial and need to be further explored. This article describes the average number and length of barbs increasing from 67 to 100 and from 11.90 to 26.00 mm with a rise of single down mass, respectively. The mass of a single down is lognormal, and the average value and maximum probability value of individual down mass are 1.46 and 0.62 mg, respectively. There is no significant difference in a helix or b sheet contents through peak deconvolution of the Fourier transform infrared spectroscopy of the barbs and barbules. The compression recovery rates of single down are 58.29% and 58.94% in the x–x and y–y directions, respectively, due to the almost same structure in both directions. Further, the compression recovery rates of down with filling masses of 0.5, 1.0, and 1.5 g decreased by 6.79%, 5.00%, and 7.31% after five consecutive compression cycles, respectively. The thermal conductivity of the down assembly first decreases to 0.024W( m[1 ( ]C[1 and then increased with the compressive deformation, because the relative density and contact points of down fibers are changing. The study into the morphology structure, compression, and thermal properties of down will inspire the design and development of future synthetic insulation materials. [ABSTRACT FROM AUTHOR]

Personal protective clothing (PPC) is required in a variety of sectors and is important from both a safety and a thermal management standpoint. Materials used in PPC play a key role in protection. Extensive research has been conducted on the risk variables that lead to thermal load and the corresponding functional properties of PPC, particularly in high-risk categories. In contrast, despite the fact that employees who wear this type of PPC constitute a major fraction of the industrial workforce, relatively little study has been undertaken on PPC materials in low-risk categories and their thermal management properties. For this study, four new PPC materials were specifically engineered to have improved thermal attributes and were compared with four existing PPC materials of equivalent protection levels, as well as four summer-season civilian materials, to determine the most suitable materials for use in hot outdoor environments. We investigated and compared the thermal management properties of these novel materials, including liquid moisture transfer, thermal and water vapor resistance, and air permeability, to those of current materials used in low-risk PPC as well as civilian materials. The results demonstrated that the new PPC materials had improved thermal and vapor resistance; superior liquid moisture transfer properties; higher air permeability; and were lower in mass and thickness than the existing PPC materials. Furthermore, the new materials compared favorably with the civilian materials in a number of these attributes. The new materials should be included in low-risk PPC designed for use in hot outdoor conditions. [ABSTRACT FROM AUTHOR]

The thermal property of the functional bionic fabric is affected significantly by the asssembly of the yarns aggregation and the thermal property of the yarns that constructed the fabric. In this study, a thermal resistence model of the n -layer bionic fabric was proposed based on the geometrical configuration of yarns in each fabric layer. According to the Fourier law, thermal resistance equation and the effective thermal resistance equation of the n -layer bionic fabric were obtained as a function of the yarn diameter, the number of fabric layers, and the thermal conductivity of yarn. The results suggested that the aggregation of yarn in the fabric has a great effect on the thermal property of the fabric. In comparison with the control fabric, the bionic fabric with continuous yarn that constructed the tree-like structure in the thickness direction of the fabric presents a much lower thermal resistence with less than four fabric layers, and a higher thermal resistance when the number of fabric layers is greater than four. Moreover, the results revealed the analytical relationship between the bionic fabric and the thermal conductivity of yarn, the thickness of yarn, and the number of fabric layers. Experimental results agreed well with the theoretical prediction. This model provides a convenient method for thermal property prediction and optimization of the fabrics with complex configuration, and this method could equally well apply to investigate the thermal property of other woven fabrics. [ABSTRACT FROM AUTHOR]

Fibers procured from Anatolian goat (Capra aegagrus hircus) furs were converted into keratin microparticles by the cryogenic milling method. Single-stage mechanical milling with a 2.5 h optimal grinding time was sufficient enough to generate the desired high-quality microparticles. No chemical solvents were utilized during the production process of keratin microparticles. Structural, chemical and thermal properties of keratin microparticles were assessed using particle size analyzer, stereo microscope, Brunauer–Emmett–Teller™ surface analyzer, field emission scanning electron microscope, X-ray diffractometer, attenuated total reflection Fourier transform infrared spectroscopy, thermogravimetric analyzer and differential scanning calorimetry methods. According to the characterization results, microparticles with amorphous structure in micro size could be produced without any agglomeration during the milling process. Goat farming is usually for dairy products and their fibers have very limited use in the textile industry because of their flat structure. Therefore, the conversion of goat fibers into another product that can be used in other industrial areas is expected to contribute significantly to a sustainable economy. [ABSTRACT FROM AUTHOR]

High-density polyethylene (HDPE)/phosphogypsum (PG) or polypropylene (PP)/PG composites were produced using mass-produced PG powders and a twin screw extruder. The modification effect of calcium stearate was studied by oil absorption value, contact angle, and FTIR. XRD analysis indicated that the PG phase was affected by different calcination temperatures. The mechanical properties of the composite materials were evaluated by tensile and impact tests. The dispersion of PG in the matrix was showed by scanning electron microscope (SEM). Within the weight fraction range studied (5, 10, 15, 20, 25, and 30 wt%), the Young's modulus and tensile strength of the PG/HDPE composites increased significantly, but the impact strength and elongation at break decreased remarkably. Young's modulus and impact strength of PG/PP composites increase prominently, but tensile strength and elongation at break are significantly reduced. Thermodynamic analysis showed that PG can improve the thermal stability of composite materials. The apparent density indicated that the composite material filled with PG has the property of being lighter in weight. In these experiments, the mechanical properties of compounding PG powder with HDPE or PP were significantly improved, but the toughness of composites decreased. [ABSTRACT FROM AUTHOR]

The aim of this work was to develop and characterize polyurethane-based shape memory polymer filament yarns of a suitable diameter and thermo-mechanical performance for use in tailored multi-sectorial applications. Different polymer compositions – pure shape memory polyurethane and shape memory polyurethane composites with 0.3 and 0.5 wt.% of multi-walled carbon nanotubes or carbon black as additives – were studied. Filaments were obtained using a melt spinning process that allowed the production of the permanent and temporary shape of the shape memory polyurethane filament. Two drawing speeds (20 and 32 m/min) were studied. Characterization techniques such as the tensile test, differential scanning calorimetry, and dynamic mechanical analysis were used to investigate the shape-memory effect of the filaments. Pure and additive shape memory polyurethane filament yarns of a controlled diameter were produced. The results indicated that the pure shape memory polyurethane on the temporary shape had the highest tensile strength (234 MPa). Filaments with carbon black revealed a significant strain (335%) in the permanent shape with respect to the other filaments. The melt spinning process influenced the soft segment glass transition temperature (Tgs) significantly, with a decrease in the temporary shape (first heating) as compared to the permanent shape (second and third heating). However, only the 0.5% multi-walled carbon nanotubes additive clearly influenced the filament, increasing the Tgs by 10°C. The additives also influenced the shape-memory effect, obtaining an increased fixity ratio (up to 97%) with the multi-walled carbon nanotubes additive and an increased recovery ratio (up to 86%) with the carbon black additive. [ABSTRACT FROM AUTHOR]

This study investigated suspending two fire retardants in sugar-cane bagasse plies used for manufacturing natural fibre reinforced composites. Sugar-cane bagasse was alkali treated, blended with either APP (Ammonium Polyphosphate) or ATH (Aluminium Hydroxide), pressed and dried to form plies. Composites were manufactured using a light resin transfer moulding process with epoxy resin. Composites manufactured with fire retardant suspended plies were compared to composites with plies layered with equivalent amounts of fire retardants. The composites were characterised using thermogravimetric analysis (TGA) for thermal stability and char yield, isotropic hot disc method for thermal properties, and cone calorimeter for studying ignition and flammability. Plies suspended with APP had the highest char yield of 58% (in nitrogen), reducing to 26% in the composite form, with degradation driven by the epoxy matrix. The composite layered with ATH had the latest ignition times of 118 s when tested with a radiant heat flux of 35 kW/m2. The composite layered with APP displayed the lowest average heat release rate (179.7k W/m2), peak heat release rate (305.6k W/m2), and total heat released (135.5 MJ/kg). When assessing the fire growth, the composite layered with APP was again favourable. While the layering yielded more favourable results than the suspension of the same retardants, this study showed that a rudimentary process was able to suspend enough retardants to improve the behaviour of the resulting composites in a fire scenario. [ABSTRACT FROM AUTHOR]

The autoclave curing process of the large-scale composite stiffened panel greatly affects the manufacturing quality of the component, especially the curing quality of stiffeners and the bonding quality between stiffeners and the panel. In this paper, a multi-objective optimization method is developed to optimize the curing cycle for the composite T-stiffened fuselage panel, which aims to minimize the temperature difference within the component to achieve better forming quality. The autoclave curing model considering thermal properties of composites is established and verified by the experiment first. The response surface models are then built up with the Finite Element Method (FEM) and the Box-Behnken Design (BBD). The fgoalattain algorithm is applied to solve the multi-objective optimization problem with nonlinear constraints. Results show that the maximum temperature difference of the two groups of monitoring points decreases by 22.91% and 21.42%, respectively. Besides, the total curing time is also reduced by 11 mins. [ABSTRACT FROM AUTHOR]

Natural Bouligand structure is a special class of hierarchical architectures, which have proven to be effective in enhancing its mechanical properties. In this work, we demonstrate that the thermal buckling capacity of Carbon Fibre Reinforced Plastics can also be improved by mimicking bio-inspired Bouligand architectures. A finite element approach using commercial software ABAQUS is developed to predict the critical buckling temperature of the Bouligand inspired laminated plates under thermal loading. Numerical predictions show a good agreement with analytical results obtained from the literature. The effectiveness of Bouligand-type composite laminates in enhancing thermal buckling behavior is first confirmed by comparing with unidirectional, cross-ply and quasi-isotropic laminates. We then present the effects of pitch angle and ply thickness on the thermal buckling temperature of bio-inspired Bouligand-type laminates. Finally, we conclude that the improved mechanical and thermal properties can be simultaneously achieved by the Bouligand structure of laminates as the pitch angle is increased. The present study highlights the high thermal buckling behavior of biomimetic Bouligand structure, offering a possibility in developing biomimetic composites with good trade-off between mechanical properties and thermal performance. [ABSTRACT FROM AUTHOR]

Many Asian countries have made and worn their own traditional textiles; however, due to the rapidly changing influence of western culture, today's young people prefer to wear modern clothes rather than clothes made using handwoven fabrics. In order to protect and support traditional textile communities/artisans, governments are making great efforts to preserve traditional textile communities. The purpose of this study was to measure the thermal comfort properties of selected handwoven textiles made in Thailand. The results showed no significant difference in terms of thermal comfort between handwoven fabrics combined with linings (fusible and nonfusible). The advantages of the fusible lining include giving support to the handwoven fabric structure, particularly along the seams, and assistance against fabric fraying along cut edges. The results yielded recommendations to weavers of traditional fabrics to optimize the comfort function of the fabrics when worn in traditional Thai garments. [ABSTRACT FROM AUTHOR]

With the progress of society, fiber reinforced composites have become the subject of research in the field of composite materials, in which natural fibers are widely used in the enhancement and modification of thermoplastics due to their low density, biodegradation and most wide origins. However, the hydrophilicity of special fiber is the main factor that hinders its bonding with hydrophobic polymer matrix which leads to poor interface compatibility between the fiber/matrix interface. The coupling agent can increase the nonpolarity of the natural fiber and the compatibility between the fiber and the resin. In this study, the composites were fabricated by the film stacking method, and the surface of jute fiber was treated with silane coupling agent so as to prepare jute/polylactic acid composites with good mechanical and thermal properties. The mechanical and thermomechanical results show that the combination of the coupling agent can significantly improve the interfacial bond of the jute/polylactic acid composites, leading to an efficient enhancement of comprehensive performance. [ABSTRACT FROM AUTHOR]

One of the significant challenges of developing high-performance polymer nanocomposites is the best exploitation of the potential of nanofillers. In this study, the multi-walled carbon nanotubes (MWCNTs) are exfoliated by TiO2 nanoparticles using ultrasonic waves. The obtained MWCNT/TiO2 hybrid nanofiller, in different wt.%, is infused into an epoxy (EP) matrix using an ultrasonic dual mixing (UDM) technique to obtain multifunctional nanocomposites with enhanced thermo-mechanical properties and toughness. XRD crystallography, Raman spectroscopy, TEM analysis, TGA, DMA, tensile, and 3-P single edge notch bending tests are used to investigate the properties of the MWCNT/TiO2 hybrid nanofiller and resulting composites. Results reveal that the optimum loading of MWCNT/TiO2 hybrid nanofiller (1.0 wt.%) in EP matrix provides 23.5%, 39.8%, and 46.8% improvement in storage modulus, tensile strength, and fracture toughness, respectively, compared to those of neat EP. The FESEM images of the fractured surface of nanocomposite specimens confirm the cluster-free distribution of MWCNTs in the EP matrix ensuring enhanced thermo-mechanical properties and toughness. [ABSTRACT FROM AUTHOR]

A novel phosphorus- and nitrogen-containing flame retardant (APNTHE) was synthesized through the reaction of N, N, N ′, N ′-tetrakis (2-hydroxypropyl) ethylenediamine, phosphoric acid and urea. Then, the APNTHE solution with a concentration of 120 g/L was used for the preparation of flame retardant cotton (FR-cotton). The elemental compositions, surface morphology, thermal stability and combustion behavior of the cotton before and after modification were investigated. Thermogravimetric (TG) analysis showed that the char residue of the treated fabric at 800°C was as high as 35.09% under a nitrogen atmosphere. Flammability tests after different LCs indicated that FR-cotton had durable flame retardancy. Compared to the blank sample, the peak of heat release rate and total heat release of the FR-cotton decreased by 91.89% and 90.53%, respectively. The char residual and TG-Fourier transform infrared spectroscopy analysis illustrated that APNTHE played a flame retardant role both in the gas phase and the condensed phase. All the results demonstrated that APNTHE can be regarded as a prospective flame retardant for cotton. [ABSTRACT FROM AUTHOR]

Thermal insulation is a good strategy for saving energy and reducing the emission of CO2 especially when produced locally with ecological materials. The hereby document aims at evaluating the thermal and mechanical properties of eco-composite materials based on plaster and wood waste or granular cork. The proportion of used additives were respectively 20 and 30%. Two wood waste types were used as sawdust and wood chips; several granular sizes were used for granular cork. The thermal characterization consists of determining the thermal conductivity, and thermal effusivity of all samples. Flexural and compressive strength were also tested. Results show that the composite materials with 20% wood shaving, 20% granular cork size 3.35–6.7 mm, and 30% sawdust have improved thermal performance with acceptable mechanical resistances. The thermal simulation proves that using these composite materials as plasterboards in buildings can generate thermal energy gain about 38%, compared to reference building. These results indicate that the use of ecological composites based on plaster has a promising future in thermal building insulation. [ABSTRACT FROM AUTHOR]

The growing awareness of socioeconomic and environmental issues and the high percentage of petroleum resources consumed and new environmental regulations have fueled efforts to develop innovative, cutting-edge, environmentally friendly materials with a wide range of applications. Due to environmental and sustainability concerns, the advancement of biocomposites has resulted in tremendous breakthroughs in green materials in this century. Their primary goal is to replace current synthetic petroleum-based composites with natural resources. Materials derived from nonrenewable petroleum-based sources are hazardous and expensive to produce; on the other hand, biocomposites derived from natural sources are biodegradable, recyclable, non-abrasive, and compostable and have properties comparable to synthetic fiber composites. Natural fibers are low-cost, lightweight, biodegradable, renewable, and environmentally friendly alternatives to synthetic fibers like glass and carbon fiber. The long-term viability of natural fiber-based composite materials has led to increased use in various production industries. However, the manufacturing process of natural fiber-based biocomposites is still plagued by some difficulties, such as poor adhesive propensity, moisture absorption, poor fire resistance, low impact strength, and low durability. This review provides a panoramic view to provide insight into different aspects of biocomposites based on natural fibers and polymers in terms of properties and applications, which will pave the way for future biocomposites research in academic and commercial contexts. [ABSTRACT FROM AUTHOR]

In this paper, poly- m -phenylene isophthalamide (PMIA) staple fibers were dissolved in a LiCl/ N, N -dimethylacetamide solvent system in order to prepare PMIA nanofibers via the electrospinning method. The mean diameter of the nanofiber was between 72 and 247 nm and gradually increased with increasing LiCl concentration. PMIA nanofibers were characterized by scanning electron microscopy, Fourier transform infrared spectrometry, a thermogravimetric analyzer and Brunauer–Emmett–Teller analysis. Besides, the tensile strength of PMIA nanofiber yarns was tested and analyzed, combining the orthogonal array method. The results showed that the diameter and uniformity of nanofibers decreased gradually with increasing PMIA and LiCl solution concentration. The thermal properties, the specific surface area and chemical structures of PMIA nanofibers were improved comparing with PMIA stable fiber. It was found out that the LiCl concentration could influence the interactions among polymer molecules and caused the fibrils to wrap around each other, forming fiber clusters. The LiCl concentration was the most important factor affecting the tensile strength of PMIA nanofiber yarn. [ABSTRACT FROM AUTHOR]

Silicon dioxide (SiO2) nanoparticles can be used as reinforcing material for composites due to their favorable characteristics. However, they are commonly subjected to surface treatments with silane coupling agents to achieve fine dispersibility and better mechanical interlocking at interface. In this study, the silane-coated SiO2 nanoparticles (as received) were used as secondary reinforcement without applying additional silane treatment process. KH550 and KH570 silane-coated SiO2 nanoparticles were dispersed, respectively, into polymer matrix, and then the modified matrix was reinforced with glass fibers. Silanized SiO2 filled glass fiber reinforced polymer (GFRP) nanocomposites were investigated for physical, mechanical, morphological, and thermal properties. Depending on the nanoparticles' ratio and silane coating, the increments were obtained till 10% for tensile strength, between 18.40% and 75.26% for flexural strength, and till 81% for impact strength. SEM confirmed that the enhancements could be attributed to the improved interfacial adhesion between the modified matrix and fiber reinforcements. The void contents within the polymer nanocomposites decreased by 38%–54% compared to a pure one. DSC and TGA examinations revealed that silanized SiO2 nanoparticles provided a better curing behavior (10% increase in Tg for 3 wt.% KH550-SiO2) and improved thermal stability for the GFRP composites (increase in Tend values by 50–70°C). Generally, KH550 silane-coated SiO2 has provided enhanced interface strengthening, leading to better characteristics for GFRP composites since the amino functional groups contained in KH550 have more favorable integration with epoxy matrix. [ABSTRACT FROM AUTHOR]

Clothing thermal and wet comfort relates to the heat and moisture transport properties of clothing as one of the most important factors in determining whether or not a garment is desirable to customers. It is important to develop winter textiles by optimally combined technology of hygroscopic heat generation and moisture management to maintain warm dry skin for the active wearer. In this work, six multilayer hygroscopic and exothermic fabrics made up of different functional yarn compositions were designed and fabricated based on ergonomic principles. Their thermal wet comfort properties were investigated compared with seven plain knitted fabrics. Air permeability, moisture management characteristics, thermal physiological properties, and hygroscopic heat generation performances were used to assess thermal and wet comfort properties. Their correlations with yarn composition were explored. Multilayer knitted fabrics with a designed knitted structure and wettability gradient demonstrated evenly hygroscopic exothermic properties and excellent directional moisture transport performances. This has the potential to reduce the phenomena of high temperature and heat concentration following moisture absorption The fabric made up of profiled polyester and a low proportion of cotton blend as an inner layer and a high proportion of modified polyacrylate and viscose blend as a middle layer was verified to have superior moisture management characteristics and evenly hygroscopic exothermic properties. [ABSTRACT FROM AUTHOR]

The present investigation aimed to understand the physicochemical properties of the new cellulosic fiber extracted from the bark of Silybum marianum (SM), in view of using it as a potential reinforcement for polymer composites. The morphological and anatomy, physical, thermal and mechanical properties of fibers were firstly discussed in this paper. The Silybum marianum fibers (SMF) were characterized by scanning electron microscopy, Fourier transform infrared, thermogravimetric analysis (TGA), optical microscope, X-ray diffraction (XRD), and single fiber tensile test. The average Young's modulus and the breaking stress data presented by the fibers are 15.97 GPa and 201.16 MPa, respectively. XRD reveals the presence of cellulose with a crystallinity index of 45%. Thermal stability (250°C) and maximum degradation temperature (357.72°C) of the SMF are established by the thermogravimetric analysis. An analysis of the mechanical properties was carried out on a population of 35 samples using Weibull statistics with two and three parameters. [ABSTRACT FROM AUTHOR]

A new bio-composite material appropriate for building thermal insulation is proposed. The hydrophilic, thermal, and mechanical properties of composites made with Posidonia-Oceanica leaves, are experimentally investigated. The effect of two different sizes of fibers (natural and crushed leaves) as well as the effect of the chemical treatment (1% sodium hydroxide) are studied. For this purpose, different parallelepipedic specimens of dimensions 270 × 270 × 30 mm3 (thermal properties tests) and 160 × 40 × 40 mm3 (mechanical properties tests) were prepared by varying densities of leaves (0, 5, 10, 15, 20, and 30% by volume). In comparison to the fiber size effect, the results reveal that fiber loading has a significant impact on the mechanical and thermal characteristics of composites. Alkali treatment can improve the compressive and flexural strength of bio-composites. The novel bio-composites have low thermal conductivity (0.09 W.m−1K−1 when 30% of reduced size Posidonia-Oceanica leaves were loaded into the reference mortar) and acceptable mechanical performances. Results also show (1) The addition of treated fiber improves the ductility of the material. (2) The fracture toughness is 75% greater than reference mortar. (3) The use of crushed fibers decreases the composite's mechanical strengths. (4) The flexural strength decreases with the fibers content and increase after 1% sodium hydroxide treatment. It can be concluded that the proposed bio-composite can be employed as thermal insulation material. [ABSTRACT FROM AUTHOR]

The thermal conductivity of silicone rubber is very low and does not meet the required thermal conductive applications, so inorganic fillers are added to increase heat transfer which ultimately improves the thermally conductive path. In this study, silicone rubber/hexagonal boron nitride composite was synthesized by the hydrolysis-polycondensation method to enhance the thermal conductivity of the material while retaining acceptable flexibility properties. The introduction of MQ resin reduced crosslink density, thermal stability, tensile strength, and hardness of the silicone resin composite and improved elongation. The addition of vinyl-based MQT and aluminum-based MQT resins improved the properties of the silicone rubber, while the addition of vinyl-based MQT resin reduced the crosslink density, tensile strength and hardness, and improved its elongation and thermal stability properties. While aluminum-based MQT resin did not have a significant effect on crosslink density, tensile strength, or hardness, it also improved elongation and reduced thermal stability. The high filler concentration of hexagonal boron nitride in the composite enhanced thermal conductivity up to 3.253 Wm−1 K−1, while it reduced tensile strength to 1.248 MPa and elongation to 22% but increased hardness up to 75 shore A. The addition of silicone resin improved the thermal conductivity of all MQ, vinyl-based MQT3 and aluminum-based MQT3 resin composites up to 3.661, 3.962 and 4.817 Wm−1 K−1, respectively. For the same three resins, tensile strength was increased up to 1.274, 1.290, and 1.312 MPa, elongation at break was raised to 125%, 188%, and 150%, and hardness was reduced to 69, 71, and 72 shore A, respectively. The addition of silicone resin also showed an effect on density, volatile content, flame resistance, and volume resistivity. [ABSTRACT FROM AUTHOR]

During machining, the cutting fluids play an essential role in cooling and lubrication. In order to reduce the friction forces, the excessive amount of the cutting fluids are generally used. This, in turn, leads to wastage of the cutting fluids which results in a serious impact on the environment, health and cost of production. Therefore, the judicious use of lubricants is the foremost concern in the manufacturing industry. In order to mitigate these drawbacks, various alternatives have been developed in the last decade. In the present paper, ionic liquids have been proved as favourable sustainable alternative additives in the base oil. The effect of alkyl chain length of ionic liquids with base oil on the thermo-physical and tribological characteristics of cutting fluids including viscosity, wettability, anticorrosion behaviour, thermal stability, and coefficient of friction have been analysed. In the present study, pyrrolidinium and hexafluoro-phosphate (PF6) have been used as cation and anion, respectively, with rice bran oil as base oil. The five different ionic liquids have been dispersed in base oil by 1.0 wt%. It has been found that longer alkyl chain length showed the favourable results as compared to the shorter one. Results indicated that ionic liquid based cutting fluid attained ample enhanced thermophysical and tribological properties as compared to the neat rice bran oil. There has been 5.08% and 4.29% improvement in viscosity and thermal conductivity for IL4 + RBO in comparison to neat RBO. In addition, the wettability, coefficient of friction, and wear volume have been reduced by 20.34%, 53.79% and 57.87% correspondingly. [ABSTRACT FROM AUTHOR]

This study proposes that green composites using recycled plastic bags (PEr) extruded with pineapple fiber waste (PR) from a juice industry to increase pineapple's economic value stimulate practices that prioritize recycling and development of new materials. PEr composites were prepared using PR as a filler, using different fiber loadings of 5, 10, and 15 wt%, and the use of a coupling agent, prepared via extrusion and injection molding. The samples were investigated by Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis, inflammability, mechanical tests (tensile, impact, and shore hardness), scanning electron microscopy, and water absorption tests. FTIR results demonstrated that the addition of PR to the PEr caused a decrease in the characteristic bands of neat PEr, evidencing the chemical interactions. Thermal analysis showed that the addition PR decreased composites' thermal stability, causing relatively higher percentages of char compared to neat PEr, which increased the burning rate of composites, except for PEr/15PR and PEr/5PR-C. Green composites exhibited higher tensile modulus and hardness than PEr, but the impact tests presented a decrease in the fibers' addition to the PEr due to the reduction of toughness and resilience. SEM of fractured surface composites presented microcracks, voids, and fibers breakage in the interface. The composites showed low water absorption (up to 0.804%). The coupling agent's use presented a low influence on the mechanical and thermal properties and a slight decrease in water absorption. These results demonstrate o potential of the reuse of plastic bags and industrial waste for green composites. [ABSTRACT FROM AUTHOR]

Exploiting the boundless potential of multi-walled carbon nanotubes (MWCNTs) is the critical issue in developing multifunctional nanocomposites. In this study, the MWCNTs are exfoliated by ZrO2 nanoparticles using the ultrasonication technique. The obtained MWCNT/ZrO2 hybrid nanofiller is infused in the epoxy matrix to produce multifunctional nanocomposites with superior thermo-mechanical and anti-corrosive properties. The physical, morphological, and structural properties of MWCNT/ZrO2 hybrid nanofiller are successfully studied by using XRD crystallography, Raman spectroscopy, and transmission electron microscopy analysis. The chemical interaction between the MWCNT/ZrO2 hybrid nanofiller with the epoxy (EP) matrix is evaluated using FTIR spectroscopy. Results indicated that the corrosion protection performance of mild steel coated with MWCNT/ZrO2 hybrid epoxy nanocomposite (MNC) is considerably increased at 1.0 wt.% of MWCNT/ZrO2 hybrid nanofiller by reducing the corrosion rate from 8.82 MPY to 56 × 10−3 MPY. Furthermore, the tensile strength and lap shear strength of MNC with the same loading content is improved by 67.8% and 58.04%, respectively, compared to neat EP. The field emission scanning electron microscopy images of tensile fracture surfaces of MNC (1.0 wt.%) confirm the cluster-free uniform dispersion of MWCNTs in the EP matrix. [ABSTRACT FROM AUTHOR]

Fabrics produced by the melt-blown nonwoven process have the advantage over competing materials of possessing an ultrafine fibrous and porous structure. However, their brittleness and poor toughness restrict their wider application. There is increasing demand for nonwovens that have high stretchability and elasticity while maintaining a melt-blown structure. In this study, polypropylene (PP) and styrene‐ethylene/butylene‐styrene copolymer (SEBS) were blended at different ratios and subsequently used in the melt-blowing process. The morphology of the blends displayed a co-continuous structure when the ratio of SEBS to PP in blends was similar. Furthermore, it was found that all the blends had good spinnability from the melt-blowing process during rheological and thermal properties tests. All the elastic melt-blown nonwovens fabricated in this research had elongations higher than 400% and elastic recoveries higher than 50%, which was indicative of good elasticity. Meanwhile, the nonwovens maintained fine fiber diameters and good filtration properties, in keeping with traditional melt-blown nonwovens. [ABSTRACT FROM AUTHOR]

Materials design and development continue to be more relevant as applications continue to rise for additively manufactured carbon-fiber-reinforced-plastic (CFRP) composites. Plastic matrixes bond and protect the fiber and help to transfer load through the composite to support intended applications. This makes it more necessary to understand the influences of thermoplastic matrixes on the mechanical performance of the composites fabricated through the additive manufacturing (AM) technique. This study investigated Acrylonitrile–Butadiene–Styrene (ABS) and Polyamide (PA) matrixes, which represent the bulk of the amorphous and semicrystalline engineering-grade thermoplastics matrixes, respectively, used in CFRP composite applications. Mechanical properties: tensile, compression, flexural, and thermal properties were examined, with the results showing the thermoplastic matrixes compositions and morphologies influences on the mechanical properties. The CF-PA was found to offer superior strength, ductility, and toughness because of their close-packed ordered lamellar matrix morphology, while the CF-ABS was found to offer superior modulus because of their loose morphology which more easily rearrange in reaction to stress upon elastic deformation. The mechanical properties results were reinforced by the fracture failure modes and the thermal analysis results which showed the CF-PA composite's ability to withstand higher mechanical performance and temperatures before failure. [ABSTRACT FROM AUTHOR]

Carbon nanotubes (CNTs)/epoxy composites are composed of CNTs, epoxy resin, and the interphase between them. The micro-morphology of the interphase has a significant influence on the macro-properties of composites, which is mainly attributed to the difference in the interaction between CNTs and epoxy resin. However, a systematic research on the interaction between CNTs and epoxy resin on composite properties is still insufficient. In this paper, the surface properties of three types of functionalized CNTs, the adhesion forces between the typical functional groups and epoxy groups, as well as the curing characteristics and the thermal properties of the CNTs/epoxy composites were investigated by using experimental methods like surface energy analysis, atomic force microscopy, and differential scanning calorimetry. This paper performed direct measurements on the interaction between CNTs with functional groups and epoxy resin. Moreover, it provided several experimental evidences for the mechanism of interfacial interaction affecting thermal properties of CNTs/epoxy composites. It indicated that it is conducive to form covalent bonds at the CNTs/epoxy composite interface when there is a strong interaction between CNTs and epoxy resin, and the thermal property could be improved finally. [ABSTRACT FROM AUTHOR]

Bismaleimide (BMI) resins are used in carbon fiber reinforced composites for high-temperature applications. Conventional BMI resins require high cure and post-cure processing temperatures, which limit fabrication methods and contribute to residual stress and microcracking. Recently, BMIs with lower cure temperatures have been developed; however, little data on the properties of low-temperature cure carbon/BMI composites are available in the open literature. In this study, processing and properties of a low-temperature cure BMI resin system, referred to here as BMI-2, were evaluated. Along with evaluation of neat resin properties, multi-directional woven carbon fiber reinforced BMI-2 composite laminates were fabricated by an out-of-autoclave, vacuum-bag-only resin infusion method. New data on the mechanical, thermal, and moisture absorption properties are presented. It was found that the resin infusion method produced laminates with fiber volume fraction of approximately 55% and immeasurably low void content. BMI-2 was found to attain a degree of cure of 96% and glass transition temperature of 366°C following a 163°C cure cycle. Cured laminates did not suffer from process-induced cracking at the inter- or intra-laminar levels. Tensile strength and modulus of quasi-isotropic specimens with woven AS4 carbon fiber were 443 MPa and 47.6 GPa, respectively, and failure under quasi-static tension occurred by delamination. Compression strength was stable across a wide temperature range, with quasi-isotropic specimens retaining 60% of their room temperature compression strength at 260°C. Equilibrium moisture content of composite specimens was 1.2% by weight. [ABSTRACT FROM AUTHOR]

In this work, recycled high density polyethylene (rHDPE) was compounded with regenerated tire rubber (RR) (35–80 wt.%) and reinforced with recycled tire textile fiber (RTF) (20 wt.%) as a first step. The materials were compounded by melt extrusion, injection molded, and characterized in terms of morphological, mechanical, physical, and thermal properties. Although, replacement of the rubber phase with RTF compensated for tensile/flexural moduli losses of rHDPE/RR/RTF blends because of the more rigid nature of fibers increasing the composites stiffness, the impact strength substantially decreased. So, a new approach is proposed for impact modification by adding a blend of maleic anhydride grafted polyethylene (MAPE)/RR (70/30) into a fiber-reinforced rubberized composite. As in this case, a more homogeneous distribution of the fillers was observed due to better compatibility between MAPE, rHDPE, and RR. The tensile properties were improved as the elongation at break increased up to 173% because of better interfacial adhesion. Impact modification of the resulting thermoplastic elastomer (TPE) composites based on rHDPE/(RR/MAPE)/RTF was successfully performed (improved toughness by 60%) via encapsulation of the rubber phase by MAPE forming a thick/soft interphase decreasing interfacial stress concentration slowing down fracture. Finally, the thermal stability of rubberized fiber-reinforced TPE also revealed the positive effect of MAPE addition on molecular entanglements and strong bonding yielding lower weight loss, while the microstructure and crystallinity degree did not significantly change up to 60 wt.% RR/MAPE (70/30). [ABSTRACT FROM AUTHOR]

This work aims to characterize the influence of hygrothermal conditioning on the mechanical and thermal behavior as well as the fractographic aspects of the interface of poly(ether imide) and glass fiber composite joints welded by electrical resistance using 400 mesh of AISI 304 stainless steel. The composites were mechanically characterized by Lap Shear Strength (LSS) and End Notched Flexure (ENF) testing to investigate maximum shear stress and energy from mode II interlaminar fracture toughness. Fractography was performed by SEM, while the influence on glass transition temperature and working temperature were evaluated by Dynamic-Mechanical Analysis and thermogravimetry. In the conditioned samples, the mechanical properties reduced 23% in the LSS test and 28% in the ENF test, while the fractography studies revealed elements of interlaminar and intralaminar fracture in both conditions. Thermal properties did not change significantly to disqualify this composite when applied to welding. [ABSTRACT FROM AUTHOR]

The effective means to solve material wear is to develop self-lubricating composite materials with excellent tribological, thermal, and mechanical properties. Herein, the composites of reduced graphene oxide (r-GO) nanosheet decorated with Silicon Carbide (SiC) were facilely prepared with employing a silane coupling agent, and the corresponding r-GO/SiC/thermosetting polyimide (r-GO/SiC/TPI) nanocomposite films were obtained by in situ polymerization method. The mechanical, tribological, and thermal properties of these nanocomposite films were investigated. When the content of r-GO/SiC was at 1.0 wt%, the compression strength and compression modulus of the composite increased by 37.7% and 47.3%, respectively, which were much higher than that of TPI composites addition of r-GO or SiC alone. Furthermore, r-GO/SiC/TPI composites also exhibited the lowest wear rate and friction coefficient in these reinforced TPI nanocomposites. When the content of r-GO/SiC was 0.8 wt%, particularly, the friction coefficient and wear rate of r-GO/SiC/TPI decreased by 22.8% and 79.8% compared to pure TPI, respectively. Additionally, trace amount r-GO/SiC hybrids also significantly enhance the thermal stability of TPI matrix. Compared to the polyimide composites reinforced by common nano-scale inorganic fillers, the outstanding mechanical and tribological properties of this r-GO/SiC/PI composites could be attributed to the ball on plane structure of GO/SiC, which lead to crack reflection, strength increment. These r-GO/SiC/TPI composites demonstrate the promising potential to be used as high-performance tribological materials in industry applications. [ABSTRACT FROM AUTHOR]

Combining polylactic acid (PLA) with waste fibers to produce reinforced biocomposites is of top interest to replace conventional polymers for environmentally friendlier materials. Natural fibers have a remarkable effect on the mechanical and thermal properties of the biocomposites. This reinforcing effect strongly depends on the chemical compositions of fibers, which will also influence the susceptibility of the biocomposites to abiotic and biotic degradation processes. This study evaluated the effect of agave and coir waste fibers over the abiotic and composting degradation of PLA-based biocomposites. Compression-molded PLA/agave and PLA/coir biocomposites using GMA-g-PLA as compatibilizer were subjected to accelerated weathering. Weathered and unweathered samples were further submitted to water absorption to analyze their hydrolytic degradation and composting for biotic degradation. Both fibers showed significant influence on biocomposites degradation. The role of the fibers in UV and hydrolytic degradation was positive for impact properties since the biocomposites were less affected than PLA. Water uptake was increased with fiber addition, while hydrolytic degradation was decreased. The weathering (abiotic degradation) accelerated the PLA biodegradation rate. In general, the results showed that adding both fibers to PLA could help its outdoor performance, maintaining the biodegradable characteristics of these materials. [ABSTRACT FROM AUTHOR]

The market for sports-abaya in Saudi Arabia is growing due to an increasing participation rate of Islamic women in fitness and sports activities. As mandated by religious law, an abaya must be worn over daily clothes or sportswear by women in order to hide their body contour. The additional layer of the abaya will affect thermal comfort and performance of the wearer. Hence, a sports-abaya needs to be specifically designed to facilitate thermal comfort. This necessitates the selection and evaluation of fabrics appropriate for use in the production of sports-abaya. This study compared two fabrics (100% cotton knit and 100% polyester woven) for their air permeability, thermal resistance and evaporative resistance. The fabrics were then incorporated as sole variable into two models of sports-abaya. The thermal properties of these abayas were evaluated using a female thermal manikin in both standing and walking positions. Comparison was made with the results of a traditional abaya. The research work revealed that polyester woven fabric has a higher air permeability (44.9 mL/cm2/s) than cotton knitted fabric (24.1 mL/cm2/s). The vapor resistance of polyester fabric was lower than cotton fabric and their thermal resistant did not show any significant difference. Consequently, thermal manikin evaluation showed results favoring sports-abaya containing polyester fabric in both standing and walking positions. Furthermore, the thermal resistant and vapor resistant values of sports-abayas were lower compared with those of the traditional abaya. This leads to the conclusion that the newly designed sports-abaya containing 100% polyester woven fabric provides better thermal comfort than traditional abaya and sports-abaya containing 100% cotton fabric. [ABSTRACT FROM AUTHOR]

The research aim was to analyse the changes in the air permeability, waterproofness, surface, mechanical and thermal properties of the polyamide 6.6 fabric with a polyurethane coating before and after 1, 5, and 10 washes in the same conditions using specialized (V1) and universal (V2) laundry detergent. A new approach based on SEM and DSC techniques and assessment of surface free energy combined with standard methods was proposed to explain the nature of observed changes in waterproof and breathable material after washing treatment. SEM analysis indicated that after 10 washes the porosity of the polyurethane coating increased from 8.94% to 14.56% and 18.75% for V1 and V2, respectively. The air permeability increased from 0.747 mm/s for the reference sample to 0.766 mm/s and 0.774 mm/s after 10 washes for V1 and V2, respectively. The waterproofness of the reference sample of 992 mbar decreased with the increasing number of washes to 246 mbar and 122 mbar for V1 and V2, respectively. After 10 washes the surface free energy (γS) decreased by 18.8% and 24.3% for V1 and V2, respectively. The average tensile strength amounted to 833 N and decreased by 13.5% for V1 and by 20% for V2 after 10 washes. The glass transition temperature of the reference fabric was 47.6°C. After 10 washes it increased by 7.2°C and 8.8°C for V1 and V2, respectively. The temperatures of thermal degradation increased by 24.6°C and 22.2°C and the heat of thermal decomposition decreased by 23.6% and 15.8% after 10 washes for V1 and V2, respectively. [ABSTRACT FROM AUTHOR]