Search

Alkali treatment is commonly used to improve the fibre-matrix bond of plant fibre polymer composites. Still, there needs to be more consensus on the optimal protocol. This study seeks to identify the most effective alkali treatment protocol for flax fibres that enhances their mechanical performance without compromising the fibre strength. Flax fibres were treated with 2% and 5% sodium hydroxide at different soaking times. Single fibre tensile strength test was performed on 243 fibre samples, and the results were analysed using the Weibull distribution model. The effect of the alkali treatment on the fibre morphology was examined using microscopic imaging, functional groups using Fourier-transform infrared spectroscopy, thermal behaviour by thermogravimetric analysis and the fibre moisture absorption behaviour was also investigated. The results indicate that treatment with 2% NaOH for 30 and 60 minutes enhanced the tensile strength of the fibres. Fibre imaging confirmed the breakdown of the fibre bundles using the treatment method. FTIR analysis showed that the treatment reduced the fibres’ hemicellulose content, enhancing the fibres’ thermal and moisture absorption behaviour. The results highlight flax fibres treated with 2% NaOH for 60 minutes as the optimal treatment protocol for flax fibres used as the reinforcing phase in polymer composites. [ABSTRACT FROM AUTHOR]

Cracking increases the vulnerability of concrete structures to aggressive substances in environments. In this study, water absorption of mechanical cracked cement mortar has been monitored using acoustic emission (AE). The AE waves from the cracking and the wetting were both recorded and analysed using wavelet transform. Two analytical methods, ie wavelet energy and empirical mode decomposition (EMD), were employed to determine the entropy value of the acoustic signals. The results show that the signal of water absorption denoised by a 6-level Daubechies wavelet of order 5 (db5) exhibits lower amplitude and attenuates in a much longer duration compared to that of cracking. The time-frequency distribution, using Continuous Wavelet Transform (CWT), indicates that the maximum magnitude of the waves from water absorption is distributed in frequency of 20 ~ 70 kHz as compared to 80~160 kHz for cracking. The power spectral density of AE waves from water absorption is much less than that of cracking due to the different nature of AE sources. The entropy values by empirical mode decomposition (EMD) and wavelet for water absorption are about 0.51 ± 0.05 and 1.44 ± 0.11 of that of cracking, respectively. The distinct characteristics of the waves could be taken to identify the acoustic sources. [ABSTRACT FROM AUTHOR]

As ecological architecture and green buildings have become essential in the fight against climate change, earthen architecture has an undoubted role to play in achieving this goal because of its numerous benefits. To help providing a better understanding of the behavior of earthen materials to fulfill modern architectural needs and to preserve earthen heritages, this study aims to investigate the effect of stabilization using Portland cement and quicklime and that of reinforcement using date palm fibers on the compressive creep, ultrasonic properties, and swelling of adobes, besides their impacts on physical characteristics. One of the earthen heritages in Algeria is taken as a case study, and various adobe mixes were examined to attain this objective. The outcomes revealed that stabilization overall improved the properties of adobes, unlike the mutable impact of fibers. Stabilizers played an important role in reducing creep, while fibers reduced the creep of the unstabilized adobes and those with 6%PC-3%QL, but withdrew the positive effect that was offered by binders for adobes with 10%QL and 3%PC-6%QL. Water absorption and swelling were reduced by stabilization, but both increased with the presence of fibers. The changes in ultrasonic characteristics showed a good correlation with those of compressive strength. [ABSTRACT FROM AUTHOR]

\nHighlightsPerformance of insulating polymers is seriously impacted by water absorption. Hence, its assessment using Fick’s law and 3-core water shell model are used for a holistic understanding of water diffusion. Epoxy with organically modified montmorillonite clay of 2, 5 and 7 weight percent (wt.%) are fabricated and water diffusion is carried out for 240 hours. The results are analysed by dielectric and gravimetric approaches. The weight gain in epoxy after 240 hours is 0.42% and 0.19% at 5  wt.% of the filler. The weight gain peaks after 120 hours in all the composites and the variations from 120 to 240 hours are minimal. The weight gain rate is lowest at 96 hours, and it peaks at 120 hours and is highest at 0.00033%/hour in epoxy, and reduces to 0.0023%/hour with filler of 7  wt.%. The weight gain and weight gain rate are characteristics of the epoxy and the filler controls the magnitude. Diffusion coefficient is lowest at 5  wt.% but the differences in the other composites are limited. The effect of fillers on free volume, free volume rate and fractional free volume are correlated to the dielectric parameters. Water uptake increases the DC conductivity from 10−14 to 10−12 S/m after 240 hours and the relative permittivity increases by 40%. The water shell model, diffusion parameters and the free volume parameters are correlated to the results of DC conductivity and relative permittivity. Subtle changes induced by absorbed water is identified by the method adopted. Organically modified montmorillonite (OMMT) increases free volume irrespective of filler content.Mass gain is highest at 7 wt.% of OMMT.DC conductivity is low at 7 wt.% of OMMT.Modelling of εr and σDC correlate well to experimental results.Free volume creation is lowest at 96 hours and highest at 120 hours.Organically modified montmorillonite (OMMT) increases free volume irrespective of filler content.Mass gain is highest at 7 wt.% of OMMT.DC conductivity is low at 7 wt.% of OMMT.Modelling of εr and σDC correlate well to experimental results.Free volume creation is lowest at 96 hours and highest at 120 hours. [ABSTRACT FROM AUTHOR]

With the rapid development of 5 G technology and microelectronics, there is an urgent demand to design and develop modified polyimide films with low dielectric constant as flexible matrix materials. In this work, a diamine containing multiple side methyl and biphenyl groups was synthesized by aromatic nucleophilicsubstitution reaction and oxidation-reduction reaction, respectively. Furthermore, this monomer was used to polymerize with four different commercially available dianhydrides (ODPA, BTDA, BPDA, and PMDA) to produce a class of polyimides (PI 3a∼3d). The structures of the diamine and its PIs are characterized, and the relationship between the structure and properties of the obtained PI films is investigated. These modified PIs are easy to cast into films and have low dielectric constants and water absorption. Their dielectric constants and dielectric losses are in the range of 2.66–2.91 and 0.00579–0.00677 at 1 MHz, respectively. Meanwhile, these PIs also maintains good thermal stability, with glass transition temperatures (Tg) higher than 284 °C and 10% weight loss temperatures in the range of 496–505 °C at N2. [ABSTRACT FROM AUTHOR]

The performances of a geopolymeric binder produced without utilising conventional cement and employing as sources Calcined clay and Ground Granulated Blast Furnace Slag (GGBS) have been examined in this research. The Alkaline liquid-to-binder ratio is considered to be 0.4 and the ratio of Na2SiO3 to NaOH to 2.5. Standard mortar characteristics including setting time, consistency, water absorption and compressive strength were assessed in accordance with the ASTM and Indian standards. The results of the tests demonstrate that the consistency and initial setting time were improved as the increase in the amount of calcined into the paste of geopolymer. The maximum compressive strength (37.1 MPa at 56 days of curing) was obtained at 10% replacement of calcined with GGBS then strength was declined after increasing the proportion of calcined clay and the water absorption (6.5% at 56 days of testing) values were reduced at 10% replacement of GGBS with calcined clay then it was increased as increased the proportion of calcined clay. The cluster and regression analysis were also done in this study. [ABSTRACT FROM AUTHOR]

Aiming at the problems of short inhibition life and low efficiency of physical inhibitors for the prevention and control of coal spontaneous combustion, this paper utilizes super water-absorbent (SAR) resin with tea polyphenol (TP) and vitamin C (VC) to prepare an inhibitor that can continuously and efficiently inhibit coal spontaneous combustion. Through the procedure of heating, thermogravimetric experiments are performed to characterize the inhibition performance of super-water-absorbent antioxidant-type inhibitor, and the change of active functional groups in the original coal and inhibited coal samples. The experimental results show that the super-water-absorbent antioxidant retardant can inhibit the coal spontaneous combustion in the low-temperature oxidation stage by absorbing heat through water evaporation and lowering the temperature to isolate the oxygen, and in the super-temperature stage by reducing the number of active functional groups in the coal. Compared with that of the original coal, and the water retention of the highly absorbent resin played the role of cooling and oxygen barrier for the coal; the apparent activation energy of the resisted coal samples in the spontaneous combustion in the three stages of oxygen uptake and weight gain, pyrolysis, and combustion increased by 41.02 kJ/mol, 92.58 kJ/mol, and 133.7 kJ/mol. In the process of temperature increase, the content of -OH, -CH2, -COOH, C=C, and C-H functional groups in the resisted coal samples was lower than that of the original coal, and -OH and -CH2 in the resisted coal samples showed a tendency to decrease, which reduced the reactive functional groups. Therefore, the superabsorbent antioxidant inhibitors can inhibit coal spontaneous combustion reactions by reducing the activity of coal molecules and delaying the process of coal spontaneous combustion reactions through releasing water, absorbing heat, and covering oxygen. The results of this study can be used as a reference for the field of inhibition of coal spontaneous combustion by chemical inhibitors. [ABSTRACT FROM AUTHOR]

Datong long-flame coal from China was pyrolysis with superheated water vapor at 300°C to 536°C. Chemical and physical changes of long flame coal, including composition, weight loss, pore fracture structure, density, and water absorption were tested, and the qualitative and quantitative relationships among these changes were analyzed. superheated water vapor pyrolysis removes moisture and volatile components from long flame coals and increases the fixed carbon content. After superheated water vapor pyrolysis, the O/C and H/C atomic ratios of long flame coal decreased due to the decomposition of oxygen-containing functional groups and chain aliphatic hydrocarbons. superheated water vapor pyrolysis increased the porosity of long flame coal by material removal and matrix fracture. Material removal occurs throughout the pyrolysis process but matrix fracture occurs only at the initial stage of the conversion of solid organic matter to oil and gas products. The expansion of pore fractures in long flame coal caused a significant decrease in apparent density and an increase in water absorption. Quantitative analysis revealed the forced water absorption of long flame coal was quadratically polynomial with respect to porosity. [ABSTRACT FROM AUTHOR]

Recently, bio-composites have attracted much attention due to their potential applications in various industries. The most notable benefits are the product's low cost, biodegradability, lightweight, availability, and ability to solve environmental issues. The present research utilizes ash gourd (Benincasa hispida) peel, a food waste, as a filler material to produce epoxy (EP) composites. The effect of ash gourd peel particle percentage (ranging from 0 to 25 wt.%) was studied on the developed composites' mechanical and thermal properties and water absorption behavior. The maximum tensile strength, flexural strength, and shore D hardness were 47.52 MPa, 2409.17 MPa, and 79.6respectively, when the ash gourd peel was 5% by weight in the composite. It was observed that the mechanical characteristics of manufactured bio-composites are negatively affected by the high concentration of ash gourd peel particles in the epoxy matrix. Also, increasing ash gourd peel particle fraction increases the water absorption of composites when immersed in distilled, sea, and tap water. The composite with 5% filler by weight absorbs water at a minimal rate when immersed in seawater. Thermogravimetric analysis was conducted to investigate the newly developed composite's thermal behavior. In addition, a morphological examination of the fractured surfaces was carried out with assistance from a scanning electron microscope. The work presents ash gourd peel particles as the potential alternative to be used as filler in composites. [ABSTRACT FROM AUTHOR]

The preparation and characterization of composite materials composed of polypropylene (PP) as the base mixed with halloysite nanotubes (HNT) at various weight percentages (0.5, 1.5, and 3 wt.%) using a melt extrusion method operated at a temperature between 190 °C and 200 °C is described. The impact of the addition of the HNT filler on the PP nanocomposites was investigated based on the thermal and mechanical properties. The thermal characterization was conducted by differential scanning calorimetry (DSC). Significant increases in the rheological properties were observed with the addition of a high content of HNTs. The water absorption decreased with increasing HNT. The SEM micrographs showed that the HNT fillers were homogeneously dispersed throughout the entire PP matrix. [ABSTRACT FROM AUTHOR]

Present research critically investigates drying sensitivity and cement hydration resumption in recycled aggregate concrete (RAC). To determine minimum post-curing time for optimum strength resumption in RAC, a curing ratio (δ) is introduced. Curing ratio is defined as the ratio between post-curing duration and delay time before curing. Drying sensitivity of RAC is observed significantly lower than NAC. The maximum strength loss under drying conditions is 25.9% in RAC (OPC) and 23.2% in RAC (PPC). Strength criteria determine the curing ratios of RAC (OPC) and RAC (PPC) as 2.22 and 0.30. The maximum delay time for RAC (OPC) and RAC (PPC) is determined at 8 days and 21 days with a minimum post-curing for 17.76 and 6.63 days. The longest allowable delay produces ion penetration less than 1000 Coulombs, resistivity greater than 208 ohm-m, superior structural integrity and internal compactness, and sorptivity comparable to RACs cured after a shorter delay. [ABSTRACT FROM AUTHOR]

In this study, four distinct composite samples (Samples A, B, C, and D) were fabricated using varying compositions of biochar, rice bran, coconut coir, and epoxy matrix. Sample A, serving as the baseline with 90% epoxy and 10% biochar, exhibited moderate mechanical properties. Sample B, with 80% epoxy and 20% biochar, demonstrated significantly higher tensile and flexural modulus values, indicative of improved stiffness. Sample C, incorporating 10% rice bran alongside 80% epoxy and 10% biochar, displayed reduced mechanical properties compared to Sample B, potentially due to the lower strength of rice bran particles. Sample D, comprising 80% epoxy, 10% biochar, and 5% coconut coir, demonstrated weaker tensile properties but higher flexural modulus, suggesting enhanced resistance to bending forces. Mechanical testing, water absorption analysis, Fourier Transform Infrared (FTIR) spectroscopy, and SEM imaging provided comprehensive insights into the mechanical and chemical characteristics of the composites, underscoring their potential for diverse applications in sustainable materials development. [ABSTRACT FROM AUTHOR]

This paper investigates the effect of quarry waste sand (QWS) on the physical and mechanical properties of recycled aggregates concrete (RAC). Two sets of concretes were made one with natural sand (NS) and another with QWS sand. Five mixes with replacement ratios of 20%, 40%, 60%, 80% and 100% of ordinary coarse aggregates (OCA) by recycled concrete aggregates (RCA) were produced for each set. Tests were performed to determine slump, compressive strength, flexural strength, water absorption by immersion and shrinkage. The results showed that the mixes produced with QWS sand exhibited slightly better fresh and hardened properties. The combination of QWS sand and RCA aggregates reduces the degradation often recorded and makes RAC concrete to have the same level of performance as concrete with ordinary aggregates. Some relationships were deduced to express each performance of QWS sand-based concrete with that of NS sand-based concrete. This makes the use of this sand very practical and its modifications easily quantifiable. [ABSTRACT FROM AUTHOR]

In the present investigation, a comparison of Graphene Oxide (GO) and Functionalized Multiwalled Carbon Nanotubes (FMWCNTs) incorporated in Pozzolana Portland Cement (PPC) mortar was carried out to find their influence on mechanical and durability properties. It has been observed that Pozzolana Portland Cement Carbon-Based Nano-Composites (PCCNCs) mortar has outstanding mechanical and durability properties. The finding shows that the PPC-1G (0.0015% of GO by weight % of cement) and the PPC-1C (0.0015% of FMWCNTs by weight % of cement) showed the greatest improvement in mechanical and durability performance over the curing period of 90 days (d). When PPC-1G and PPC-1C were compared with the reference (PPC-Control) sample, their compressive strengths increased by 11.67% and 8.73%, respectively. In terms of tensile splitting strength, PPC-1G and PPC-1C had shown a 26.35% and a 20.61% increment, respectively, as compared to PPC-Control. The C-S-H gel grows efficiently in the PCCNCs mortar, as per Powdered X-ray Diffraction (PXRD) data. It is possible to determine the carbonates present in the PCCNCs mortar by using Fourier Transform Infrared Spectroscopy (FT-IR). Furthermore, the microstructural behavior of PCCNCs mortar revealed by the Field Emission-Scanning Electron Microscope (FE-SEM) indicates that the production of ettringite and needle-shaped structures contributes to the enhancement of the mechanical strength and durability properties of the PCCNCs mortar. The research paves the way for incorporating GO and FMWCNTs in cement-based materials. This tremendous advancement holds enormous promise for the advancement of the building and infrastructure sectors. Implementing high-performance mortars has the potential to increase the strength, durability, and sustainability of structures, hence contributing to the development of safer and more resilient built environments. [ABSTRACT FROM AUTHOR]

The comfort level of human being can be increased by effective noise management without damaging the external environmental resources. The burning of rice stubble particularly in rice growing Asian countries makes the situation bad to worst. Rice stubble deserve for an immediate solution of in product development for its sustainable disposal. Rice stubble, cotton fly waste were used to manufacture composite material to be used as acoustic panel. Rice stubble powder 60%, 70%, and 80%, cotton fly waste 20%, 30%, and 40% by weight, and polyurethane (PU) resin were used to manufacture composite as acoustic panels. The composites were tested for pore size, morphology, water absorbability, and noise reduction coefficient (NRC) mainly. Acceptable level of NRC and other features were achieved. This study will provide a new pathway to use the discarded challenging waste materials to manufacture wealth-generating products. [ABSTRACT FROM AUTHOR]

The affinity towards utilisation of Glass Fiber Reinforced Polymers (GFRPs) is its exceptional and distinctive properties. These are substitutional to conventional materials with added benefits upon incorporation of filler materials into the glass/epoxy polymer composites. The present work focused in order to prepare hybrid S-Glass nanocomposite samples with a mix of nano Al2O3 (1.0 Wt% to 3.0 Wt%) and nano perlite powder (3.0 Wt% to 9.0 Wt%) with different weight percentages. According to the Response Surface Methodology (RSM) and its experimental design, the hybrid S-glass/Al2O3/Nano perlite composite was prepared using hand layup process. Further, the fabricated samples were processed as per ASTM standards and the mechanical characteristics were investigated. Thus, the responses Tensile strength and Flexural strength were recorded, optimised using RSM and anlysed using Analysis of Variance (ANOVA). Also, statistical techniques were applied to verify the experimental results. The optimal weight percentages of nano Al2O3 powder and nano Perallite powders are 2% for obtaining maximum tensile strength and 3% to obtain maximum flexural strength, respectively. The water absorption test was carried for obtained optimal sample and water uptake pattern has been recorded as per ASTM D570. [ABSTRACT FROM AUTHOR]

This work investigated the effects of the crushing index and water absorption of recycled concrete aggregate (RCA) on performance of recycled aggregate pervious concrete (RAPC). It was found that the large RCA water absorption can reduce the cohesiveness between aggregates thereby leading to poor castability of fresh RAPC mixture. This would further lower the micro-mechanical properties of new cement paste and weaken the RCA/paste bonding thereby causing poorer compressive/flexural strength of RAPC. However, the poor cohesiveness at larger RCA water absorptions could create more connected pores for superior permeability. The high crushing index of RCA was disadvantageous to RAPC's compressive strength but its influence on flexural strength or permeability was insignificant. This work suggests that the RCA crushing index/water absorption should be adjusted according to specific technical requirements on strength/permeability by different layers of permeable pavements and RCA with very high water absorption or crushing index should not be utilised. [ABSTRACT FROM AUTHOR]

With the potential safety hazard of coal spontaneous combustion becomes more and more serious, in order to solve the problems of low water absorption rate and high cost of hydrogel inhibitor, in this study, a superabsorbent lignin-based composite inhibitor (SAP + SLS + Ben) was prepared. The water absorption/retention rate, micromorphology, inhibition capacity, air-leakage blocking efficiency and fire-extinguishing performance of SAP + SLS + Ben were studied. Results have revealed that: SAP + SLS + Ben had excellent water absorption/retention capacity; SEM images revealed that sodium lignosulfonate (SLS) and bentonite (Ben) provided the structural basis for the high water absorption/retention of SAP + SLS + Ben; Compared with SAP, SAP + SLS + Ben could effectively inhibit the oxidation of reactive functional groups in coal, and the amount of CO released from coal treated with SAP + SLS + Ben was significantly reduced at high temperature; The air-leakage blocking and fire-extinguishing experiments showed that SAP + SLS + Ben had good filling and blocking performance, and could effectively reduce the temperature of coal spontaneous combustion and prevent the re-ignition of coal. Hence, SAP + SLS + Ben had ideal physical and chemical inhibition properties, which could effectively prevent coal spontaneous combustion in goaf. [ABSTRACT FROM AUTHOR]

The presented research investigates the influence of braided flax woven-fabric filled with polylactic acid (PLA) polymer on interlaminar shear strength (ILSS), free vibration, heat deflection temperature (HDT) and water absorption. For this purpose, flax fibre-braided yarn and its fabric are prepared using solid braiding and plain weaving techniques. Then, PLA biocomposites are developed by solution casting and hot-press moulding processes. Shear test results showed, the addition of braided flax fibre increased the ILSS of composites compared to unreinforced PLA. Natural frequencies of the composite beams are improved with the braided flax reinforcement. Composites filled with three fabric layers showed higher frequency due to higher structural strength and stiffness associated with these composites. Bio-composites HDT is enhanced with the addition of braided flax fibre from 61.78% to 132.97%. The results of a water absorption test in distilled and seawater revealed that the composites have a relatively high water uptake in distilled water. [ABSTRACT FROM AUTHOR]

Thermal stable epoxy is indispensable for aerospace and advanced electronic application. As replacements for common thermal stable epoxy TGDDM, we previously developed several glycidyl ether type tetrafunctional epoxies. As a continuous effort to achieve higher Tg, a novel tetrafunctional epoxy with shorter spacer and lower epoxide equivalent weight (TFEP) was synthesized. TFEP was mixed with DGEBA, and cured with MHHPA and DDS, respectively. TFEP increases the Tg and char residues, and reduces the maximum weight loss rate. Tg of 30 wt%TFEP/DGEBA/DDS is higher than that of previously reported epoxies, whereas Tg of 40 wt%TFEP/DGEBA/DDS is comparable to that of TGDDM/DDS. The influences of TFEP on the Td, strength, toughness, water absorption and free volume are different, depending on the curing agents. Moreover, 30 wt%TFEP/DGEBA/DDS exhibits higher toughness and Td5%, lower water absorption, and comparable strength, compared with TGDDM/DDS, providing a better replacement for TGDDM. Besides, TFEP slightly increases the Ea. [ABSTRACT FROM AUTHOR]

The rapid urbanization and economic expansion have increased the negative consequences of environmental noise pollution. The sound that originates from various sources comes from distinct spectrums. To address the aforementioned issue, acoustic absorbers were 3D printed with varying infill patterns to absorb sound across a wide range of frequencies. Acoustic absorbers made of polylactic acid/polyhydroxyalkanoates-wood fibers (PLA/PHA-WF) were fabricated using Fused Deposition Modelling (FDM) technology, and their physical, mechanical, water absorption, biodegradation, and acoustic characteristics were measured and discussed. Acoustic absorbers printed with different infill patterns have a slight difference in density due to the size of the pores and the contact sites exhibited by the infill pattern. As a result, acoustic absorbers printed with varying infill patterns allow sound waves to enter and absorb sound at distinct spectrum levels. Modifying the infill pattern also had an effect on mechanical, water absorption, and biodegradation properties with minor deviations. The proposed biodegradable acoustic absorbers made of natural fiber composites and manufactured by FDM can be installed on building walls or roofs depending on the required acoustic absorption spectrum. [ABSTRACT FROM AUTHOR]

This paper investigates the mechanical, microstructural, and durability properties (acid/sulfate attack, water absorption, electrical resistivity, and drying shrinkage) of carbon nanomaterial cementitious mortars (CCMs). With the help of sika superplasticizers, mortars with a water-to-binder ratio (w/b) of 0.42 were fabricated. The functionalities, morphology, and microstructural behavior of the specimens were characterized by powdered X-ray Diffraction (PXRD), Fourier Transform-Infrared Spectroscopy (FT-IR), Field Emission-Scanning Electron Microscope (FE-SEM), and Transmission Electron Microscopy (TEM). The capillary suction test and acid/sulfate resistance were significantly improved in the presence of carbon nanomaterials (CNMs) in mortars. The incorporation of CNMs revealed a significant role in the process of pore refinement. The research results provide a potential new pathway to improve the toughness and durability of cement composites. [ABSTRACT FROM AUTHOR]

The treatment of sisal fiber by pozzolanic materials like kaolin and silica-fume has been explored; however, no study has modeled and optimized the effect of sisal fiber degradation treatment using calcined bentonite. Therefore, the present study investigate the effects of treating sisal fiber with different doses of calcined bentonite, bentonite calcination temperatures, and times on fiber breaking load, degradation resistance, and water absorption using the central composite design-response surface method (CCD-RSM). The best performance of the optimum treated sisal fiber selected from the CCD-RSM based on the established goal of maximizing breaking load and degradation resistance with minimum water absorption, it was obtained a calcined bentonite dose of 30.067%, a bentonite calcination temperature of 800°C, and a calcination time of 179.99 min. Based on these factors, experimentally found sisal fiber breaking load 12.87 N, degradation resistance 98.44%, and water absorption 39.05%, all are within the 95% confidence level compared to the optimum numerical suggested values. Hence, the optimum treated sisal fiber improved breaking load by 33.37% and degradation resistance by 98%, while it reduced water absorption by 60.95%, compared to raw sisal fiber. Besides these, the optimum treated sisal fiber exhibits higher surface roughness and lower porosity than the raw sisal fiber. [ABSTRACT FROM AUTHOR]

The environmental effects on the response of Date Palm Fiber (DPF) composites are explored through an in-depth analysis of water absorption behavior. This study comprehensively investigates the influence of fiber content, immersion time, and water type on mass gain. Rigorous experimentation and advanced statistical analyses quantify the percent contribution of each factor, emphasizing the dominant role of fiber content at 96.61%. While immersion time and water type contribute relatively smaller percentages (2.11% and 1.28%, respectively), their insights are invaluable for tailored composite design. The study extends to interaction effects, showcasing the combined influence of factors. Regression models, progressing from linear and reciprocal formulations to comprehensive global models, are developed. Meticulous examination of prediction accuracy, using diverse statistical metrics, highlights the superior performance of the global reciprocal model across different water types. This work provides essential insights for optimizing DPF composite design, fabrication, and application, empowering engineers and researchers to make informed decisions in industries demanding tailored water absorption behavior. [ABSTRACT FROM AUTHOR]

Composites reinforced with lignocellulosic fibers are attracting attention for use in several applications. This fact is directly linked to the advantages of using renewable lignocellulosic fibers. However, due to their cellulose-based structure, lignocellulosic fibers easily absorb water, which can affect the behavior of the composites. Surface treatments are used to reduce the hydrophilicity of fibers, but common surface treatments use chemicals, compromising the green approach of using lignocellulosic fibers. This work compares the water absorption behavior of sponge gourd-epoxy matrix composites with untreated and surface treated fibers. The effect of these treatments on the variation of the Young's modulus and damping factor of the composites during the immersion time in distilled and salt water was also evaluated using the nondestructive impulse excitation test. In addition to the commonly used surface treatments (mercerization and acetylation), hornification has also been used to reduce the use of chemicals. The results obtained show that hornification is a competitive approach to reduce the water absorption of composites, being an interesting alternative to chemical surface treatments. A relationship was established between the amount of water absorbed and the variation in Young's modulus and damping factor. Both properties stabilized when the water absorption saturation value was reached. [ABSTRACT FROM AUTHOR]

The current study examines the effect of NaOH treatment on the hardness, inter-laminar shear strength (ILSS) and water absorption behavior of epoxy composites reinforced with banana pseudostem fibers. Using the hand-lay-up method, six distinct samples are created that are composed of layers of woven and short banana fibers in both a plain and hybrid form. Plain- treated woven composites reveal the highest hardness and ILLS properties followed by the hybrid and short fiber composites. The random orientation of the fiber structure in short fiber composites results in the largest moisture absorption; this behavior is further supported by elucidating the kinetic parameters and diffusion coefficient parameters. SEM analysis confirms the improved surface of the NaOH-treated composite material. [ABSTRACT FROM AUTHOR]

Hybrid graphene filled glass/sisal fiber-reinforced epoxy nanocomposites were successfully synthesized with different weight percentages (0%, 0.25%, 0.5%, 0.75% and 1%) of graphene nanoplatelets. The objective of this study was to investigate the effect of weight fraction of graphene on the mechanical and physical properties of the hybrid glass/sisal fiber-reinforced epoxy nanocomposites such as tensile, flexural, hardness, density, void content, flammability, water absorption and thickness swelling. The hybrid nanocomposites were fabricated using the vacuum bag-assisted hand lay-up technique. Different layup sequences were achieved by changing the position of the glass/sisal fiber layers, maintaining a total of five layers in each composite. The obtained results suggested that the addition of 1% graphene nano filler into the sisal/glass hybrid composite enhanced the tensile strength by 49.7% and Young's modulus by 60%. Among GNP reinforced hybrid composites, highest value of toughness (16 J) was found in case of the composite containing 1 wt.% GNP. However, when 0.5% of GNPs were added in the composite, the flexural strength and modulus reached a maximum of 306 MPa and 25 GPa, respectively, which are 228% and 362% greater than sisal/glass hybrid composites. The water absorption of the composite sample containing 0.5% GNPs was 4.62% lower than those of other hybrid glass/sisal fiber reinforced epoxy composite. Furthermore, addition of 0.5 wt% GNP resulted in a decrease in the burning rate of the hybrid composite from 11.22 mm/min to 7.6 mm/min and from 23.13 mm/min to 20.18 mm/min, respectively. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the individual and combined effect of kaolin clay (KC) and shea nut shell particles (SSP) on the physical, strength, and durability properties of concrete. The cement content was replaced with up to 20% KC, and the fine aggregate content was replaced with up to 40% SSP. The concrete samples were cured for 7, 14, 28, and 90 days, and tested. The total SiO2+Al2O3+Fe2O3 content of the KC studied was 88.23%; hence, it possesses pozzolanic properties. Initial and final setting times of the KC pastes steadily increased to 154 min and 325 min at the 20% KC representing 37.5% and 14.4% increase over the control. The control mix obtained a workability value of 102 mm, and decreased steadily to 68 mm at the 20% KC and 40% SSP concrete mix, representing 50% reduction. Maximum compressive and split tensile strength values of 25.97 N/mm2 and 4.14 N/mm2 were obtained at the 15% KC and 30% SSP concrete, representing 9% and 5% increase over the control concrete respectively in 90 days curing. Furthermore, concrete with 15% KC and 30% SSP recorded 61.5% and 22.1% decrease in water absorption and sulfate attack, over the control concrete respectively in 90 days curing. It is concluded that the addition of KC and SSP positively influenced the physical, strength and durability of concrete, and therefore recommend 15% KC and 30% SSP replacements of cement and fine aggregate respectively for concrete production. [ABSTRACT FROM AUTHOR]

This article investigated the influence of the incorporation of metakaolin in paving blocks. Two methods of incorporation were conducted in two factories. The first method consisted of addition with 10, 15, 20, 25, and 30% metakaolin in relation to the amount of cement, and the second one analysed the partial replacement of cement in the contents of 4, 8, and 10%. The results showed that in mixtures with replacement, the metakaolin did not show improvements in all properties. In contrast, in cases with addition, the compressive strength improved, and absorption was reduced. In both methods, the abrasion resistance did not change with the incorporation of metakaolin. Finally, the addition of 10% proved to be sufficient for application in paving blocks. [ABSTRACT FROM AUTHOR]

The aim of this study was to improve the properties of 15-year-old short rotation teak wood using a succinic acid (SA) treatment without excessively increasing the weight gain. The samples were classified as sapwood (SW) and heartwood (HW). Samples were immersed in 10% concentration SA solutions (w/w), followed by vacuuming at -50 kPa for 30 minutes, and applying 7 M Pa of pressure for 2 hours. They were then analysed for specific gravity (SGs), dimensional stability, including tangential/radial ratio (T/R Ratio) and water absorption (WA), weight percent gain (WPG), chemical uptake (CU) and void volume filled (WF). Our results showed that SGs increased in treated SW and HW by 2.33% and 1.23%, respectively, as compared to the untreated wood (0.60 and 0.66). The increase in SGs was the result of SA penetration into wood cell walls. The WPG and CU values increased slightly to 5.54% and 0.87 g cm−3 for SW and 3.46% and 0.62 g cm−3 for HW, respectively. The greater increase of SGs in treated SW is due to a greater ease of treatability in SW than HW. The T/R ratio of treated HW decreased by 29.34% from the initial T/R ratio, whereas SW remained unchanged. The WA of treated SW and HW decreased by 42.67% and 55.46%, respectively compared to untreated wood. Treated wood performed better on dimensional stability, especially in terms of T/R ratio and WA values for HW. Our results show that the impregnation of short rotation teak wood with SA provides a significant increase on dimensional stability with a negligible increase in weight gain. [ABSTRACT FROM AUTHOR]

This manuscript proposes an experimental analysis for clay bricks manufacturing with partial replacement of glass wool. The physical, mechanical and durability features of bricks infused with various percentage of glass wool are tested. Thermal conductivity, water absorption, compressive strength, density and linear shrinkage are the properties tested for the bricks. These tests indicated that 4% glass wool infused bricks gave maximum compressive strength and minimum thermal conductivity compared to control brick. Life cycle assessment on construction of a residential building indicated that clay brick masonry causes the highest environmental impacts among all construction materials. The addition of glass wool to clay bricks may be a convincing alternative to traditional clay bricks. The quantity of clay used in brick manufacturing can be reduced by infusing glass wool into the bricks. [ABSTRACT FROM AUTHOR]

Autoclaved Aerated Concrete (AAC) masonry systems are widely used as partition walls in framed structures. Cracking is often reported in such walls after a certain duration of construction. Dimensional changes occurring in the masonry system under varying temperature and relative humidity (RH) conditions are some of the primary reasons for such distress. Past studies show that bedding mortar can significantly contribute to dimensional changes due to shrinkage behaviour. Most of the literature focus on characterising the influence of raw materials on the microstructure, strength, and performance characteristics of AAC blocks. In the current study, experimental studies on AAC blocks with and without bedding mortars are conducted under controlled and ambient environmental conditions to understand the impact of temperature and RH on the dimensional change behaviour of these wall systems. Furthermore, the dimensional changes observed for AAC blocks are compared with conventional clay and fly ash bricks to understand the intrinsic properties of these materials. In the experimental studies under ambient conditions, small and large-scale AAC masonry units are built and monitored for dimensional change over a period of one month. Results show that the AAC block undergoes significant dimensional change along with the bedding mortar, which is greatly influenced by the boundary conditions of the masonry system, relative humidity, and temperature. In the end, recommendations are given at the component and system levels to reduce the crack development in AAC masonry. [ABSTRACT FROM AUTHOR]

The effect of Joule heating on collapse, shrinkage, water absorption and compressive strength of timber was investigated. Results indicate that the tangential and volumetric collapse reduced significantly by ∼53% and ∼48%, respectively, with Joule heating in Eucalyptus nitens. Maximum tangential shrinkage was significantly lower, due to the reduction of collapse in Joule heated samples, as normal shrinkage was not affected by Joule heating. Reduction in collapse was achieved without a statistically significant increase in water absorption capacity or a decrease in compressive strength. Further, the estimated costs for Joule heating pre-treatment were estimated to be competitive compared to conventional steam recovery of collapse. [ABSTRACT FROM AUTHOR]

An azo-type thermosensitive crosslinking agent was prepared from azobisisobutyramidine hydrochloride (V-50) and maleic anhydride. It is then copolymerized with acrylamide (AM) and acrylic acid (AA) to prepare thermosensitive self-degradation microgel. The microgel particles are uniformly dispersed in the aqueous solution in the form of particles. Water absorption and swelling experiments of microgel showed that the water absorptivity of microgel decreased with the increase of salinity. And the microgel have the best water absorptivity under a neutral environment. The results of microgel degradation experiments showed that the higher the temperature, the shorter the degradation time, and the degradation is complete within 5 h at 100 °C. The solid residue measured by the degradation liquid is almost 0, indicating that the microgel can be thoroughly degraded at high temperature. The polymer solution after degradation can be measured by gel chromatograph and the average molecular weight is Mn=1.9 × 105g/mol. And the swelling and degradation mechanism were summarized. [ABSTRACT FROM AUTHOR]

This paper according to the requirements of the unique production process of the "Tangshan bone china" geographic indication products, specified 315 pieces of bone china 8 inch flat produced by 15 different enterprises as the experimental samples. By measuring the tricalcium phosphate content in the prime tyres and the bibulous rate value of white bone china, map out a series of C3P-ω detection data points accumulation line chart. Verified by analysis of the qualitative and quantitative relationship between tricalcium phosphate content and bibulous rate of "Tangshan bone china", derived the following conclusions: with the increase of tricalcium phosphate content of "Tangshan bone china", its bibulous rate value increases accordingly, they have approximate linear positive correlation; with 36%∼42% of C3P levels corresponding to the bibulous rate numerical range of 0.10%∼0.30%.The research results can provide scientific reference to the manufacturing enterprise for improving the production process and the quality control. [ABSTRACT FROM AUTHOR]

In this study, multi-walled nanotubes (MWCNTs) functionalized with carboxyl group are used as additives with different morphologies of chiral, zigzag and armchair to investigate the effects of three MWCNTs on the mechanical and water absorption properties of cement-based composites. Accordingly, two different concentrations of 0.05 and 0.1wt.% of MWCNTs are incorporated in the cement paste with a water-to-cement ratio of 0.4. The results indicate that the chiral sample for 0.05wt.% at the age of 7 and 28 days and 0.1wt.% at 7 days, and the armchair sample with 0.1wt.% at the age of 28 days have the highest compressive strength. The flexural strength at 7 and 28 days show that the chiral MWCNT composite has the greatest increase in strength for both 0.05 and 0.1%. The ranking of water absorption is chiral

Two crucial and challenging issues that threaten the environment are the significant amount of drinking water for concrete production and the vast quantity of waste foundry sand (WFS) generated each year. Using WFS and treated wastewater (TW) in concrete instead of sand and drinking water is a new method for solid waste recycling and water reuse. In this research study, two types of concrete mixtures were made by partial replacement of natural sand with WFS, and simultaneously using both the WFS and the TW as a part of sand and drinking water. Then, the mechanical properties and durability of mixtures were determined. The results indicated that increasing WFS and TW ratios decreased the workability of concrete. The sample contained 20% WFS plus 50% TW (W20-TW50) showed the best results, which increased compressive strength by 33.9, 19.2, and 6.2% at the age of 7, 28, and 90 days respectively, and decreased 30- minute and 24- hour water adsorption by 10.6 and 14.3% compared to the control samples. Furthermore, using WFS and TW simultaneously in concrete did not significantly impact on ultrasonic pulse velocity and rapid chloride migration. Scanning electron microscopy images indicated that the W20-TW50 sample had the best structural density and lowest pores. [ABSTRACT FROM AUTHOR]

In the structural functions of polymer components, the material's thermal stability and moisture absorption efficiency play a vital role in defining durability and physio-mechanical performance. This article emphasizes the experimental investigation of polymer (Epoxy) composites fabricated from carpet waste and Carbon nanomaterial (CBN). The supplement of Multi-wall carbon nanotube (MWCNT) into the epoxy/carpet waste polymer composites is proposed to enhance the physio-mechanical properties. The experimentation was performed to check the synergistic effect of nanomaterials in five configurations with different wt.% of MWCNT in the proposed composites. The water absorption, swelling rate, fire retardant and compression performance of the discarded carpet polymer composite modified with MWCNT have been investigated. The effect of water dipping and dry condition was completed to evaluate the composite feasibility. In addition, the fire-retardant properties of developed materials were analyzed using the fire (horizontal) setup process. The results found that incorporating the MWCNT nanoparticles into discarded carpet polymer composites can improve the compression strength. It was noticed that the few quantities of water were absorbed with less swelling effect at the 0.25 wt.% of MWCNT. The modified epoxy nanocomposites have higher specific properties values when compared to neat (discarded carpet polymer) composites. The fire retardancy properties have been enhanced remarkably with a supplement of lower nanomaterials wt.%. The findings show that the proposed carpet waste/MWCNT/polymer composites could be recommended for lightweight functions such as roadside barriers, wall tiles, toys, decorative frames, insulating materials, etc. [ABSTRACT FROM AUTHOR]

With the ingrowing awareness of environmental and energetic issues, earthen materials offer significant ecological and economic advantages. In Algeria, the Ksour (earthen buildings) remains the only witness to this type of construction. This research aims to contribute to extending the knowledge of these types of constructions to provide a proper intervention for their restoration and also help to produce adobes with good resistance and durability to reduce the renewal of plasters, which is pricey and time-consuming in the aim of declining the cost of housing, especially in rural areas. To achieve this, different mixtures of adobes were studied in order to test the effects of quicklime, cement and date palm fibers on their physical, mechanical and water resistance properties. The main results obtained showed that the addition of quicklime and cement in different combinations in adobes improves the mechanical properties. The inclusion of the DPF up to 0.5% in untreated adobes and 5% cement-stabilized adobes enhance the mechanical strengths, whereas in adobes stabilized with quicklime it leads to a decrease in their strength. The addition of cement and quicklime increases significantly the water resistance of the adobes, while the inclusion of fibers has an adverse effect. [ABSTRACT FROM AUTHOR]

The impact of surface free energy (SFE) on water absorption of roller compacted concrete pavement (RCCP) containing calcium stearate powder with different water to cement (w/c) ratios, was investigated. For this purpose, 60 cylindrical specimens were prepared with various percentages of calcium stearate powder. Water absorption, contact angle and air void tests were performed, and SFE values were calculated for various specimens. Accordingly, the addition of calcium stearate powder to RCCP reduced water absorption and SFE while increasing the contact angle. The air void content in RCCPs increased by adding hydrophobic powder. The computed tomography scans showed that the increase of voids was mainly due to the increase in number of pores with a diameter of less than 10 µm. Besides, a relationship between SFE and voids was proposed for RCCPs with different w/c ratios. This relationship indicated that with increasing the percentage of voids, the SFE decreases, which reduces capillary suction and water absorption. [ABSTRACT FROM AUTHOR]

Composites are attracting the attention of researchers nowadays because of their strength-to-stiffness ratio. The development of wood particle composites reinforced for practical purposes has been successfully attempted. This paper focuses on the application of an epoxy/hardener ratio with wood particle-reinforced polymers to develop high-strength wood composites. The percentage of wood particles in the composition varied as follows: 5, 15, and 25 wt%, with epoxy/hardener ratios of 5:0.3, 10:1, and 5:0.8. Appropriate surface modifications were made by different treatments with 0.6, 0.8, and 1 g of NaOH in 10 liters of distilled water and 0.2% KMnO4 for better adhesion of particles and epoxy. Flexural strength, impact strength, water absorption, and SEM were investigated. Nine experiments were investigated based on the Taguchi orthogonal array blend design. The composite was successfully fabricated using the conventional hand lay-up technique. The highest mean S/N ratio considered was found for wood content composition (15%), epoxy resin to hardener ratio (10%), and NaOH (1%), i.e. the main factors affecting the mean flexural and impact strength were the wood particle contents in the matrix. Water absorption was investigated. Water absorption was found to increase with wood particle content. [ABSTRACT FROM AUTHOR]

The composites industry is advancing towards producing green composites as sustainability is quickly becoming a global focus across numerous industries. Natural fiber-based composites have emerged as materials of interest in important industries, such as packaging, automobiles, and construction. False banana fiber-reinforced composite is a promising area of research owing to their partial or full biodegradability, easy availability, low cost, and considerable mechanical properties. However, more research is required to understand the full potential of false banana fiber on its composites. As a result, this review gives a basic overview of several researchers work and explain in terms of how they are prepared, what features they have, and how they are used. Particularly in regards to the mechanical and water absorption capabilities of composites, the use of false banana fibers as reinforcements in different matrices has produced interesting results. The study also found that preparation, hybridization and treatment of fiber influence the properties of false banana fiber composites. Furthermore, the development of these composites has promoted the use of environmentally friendly materials and the development of a sustainable world. This review also provides a strong and holistic outlook on the potential of false banana fibers for use as a partially or fully biodegradable composite and has not been reviewed earlier. [ABSTRACT FROM AUTHOR]

The durability of waste plastic aggregate (WPA) concrete was investigated. Concrete specimens prepared with varying proportions and shapes of WPA were prepared and their durability was evaluated. The bond between WPA and cement mortar was evaluated using scanning electron microscopy. The water absorption of WPA concrete was more than that of normal concrete. The water absorption of fibre-, flake- and granule-type WPA concrete was 16–28%, 15–35% and 14–32% more than that of control concrete, respectively. The chloride permeability (CP) of WPA concrete decreased; however, it was almost in a similar range (2200–3550 Coulombs) in all the specimens. Corrosion initiation was delayed in WPA concrete, except in the fibre-type WPA. The corrosion rate (CR) decreased by 34–82% in granule-, 23–60% in flake- and 11–20% in fibre-type WPA concrete compared to the control concrete. The compressive strength of concrete exposed to heat/cool cycles for 3 months decreased by 2–19% as the quantity of WPA increased indicating debonding between WPA and the cement mortar due to thermal variations. Due to its improved durability, concrete with up to 50% WPA can be used in construction of structures with low to moderate durability requirements. [ABSTRACT FROM AUTHOR]

Using multi-walled carbon nanotubes (MWCNTs) as an additive in a concrete mixture with an amount of 0.05 to 0.2% wt. of cement weight with a constant W/C ratio using local materials was investigated in this research. Specimens were cured in water and the Caspian Seawater curing conditions, and compressive strength tests were performed on samples up to 365 days of age. Also, flexural strength, water absorption after immersion, water permeability and porosity tests and, SEM studying were performed on specimens. Results showed that increasing the amount of MWCNTs up to 0.2% of cement weight improved the workability, compressive, and flexural strength of concrete mixtures. The addition of MWCNTs caused a mild improvement in concrete specimens' strength which were cured in Caspian Seawater compared with control concrete. In the water absorption and water permeability tests, it was seen that a lower percentage of MWCNTs decreased the results, but more amount of MWCNTs may affect vice versa. In porosity studying, it was seen that more amount of MWCNTs may cause smaller pore sizes, however may increase the porosity and CNTs' agglomeration in concrete. [ABSTRACT FROM AUTHOR]

The water absorption, chemical resistance, and biological properties are contributing factors to the overall performance of bio-composites, especially for outdoor applications. The functional properties of bio-composites are dependent on the interfacial bonding mechanism, which is controlled by the surface modification and processing parameters of natural fibers. Therefore, this study aims to investigate the potential of enhancing the mukwa/polylactide (mukwa/PLA) interface through an economic and ecological surface modification of recycled mukwa wood fibers via alkali-laccase modification. The fabricated biocomposites intended for making durable farm poles for semi-arid conditions of Southern Africa were characterized via water absorption, chemical resistance, thickness swelling, hardness, and thermal properties. Less thickness swelling and water absorption were found on the alkali-laccase/PLA composites. The lessdense (1.09 g/cm³ ) alkali-laccase treated composites showed better chemical resistance. Much swelling of the composites was observed on the 40% nitric acid (HNO3), while 60% NaOH shrunk the composites and PLA by <3.5%. The laccase/ PLA bio-composite showed a maximum thermal stability of 733 °C. The activation energy (Ea) optimized on the laccase/PLA composite with the highest of 104 kJ mol−1. Maximum crystallinity of 45.8% was achieved on the untreated/PLA composites. The alkali-laccase modification maximized the hardness of composites with 35.45 HV on alkali-laccase/PLA. [ABSTRACT FROM AUTHOR]

Natural fiber composites are being increasingly used in several fields, owing to their considerable cost, weight, and environmental benefits. The objective of this research is to study the effect of water absorption on the behavior of laminated biocomposites using flax (F) and sisal (S) fiber biocomposites with different stacking sequences (3S and 3F) and fiber orientation at 90° (F090s and S090s), as well as hybridizations (F/4S90/F and S/4F90/S) to reinforce an epoxy matrix. The kinetics of water diffusion within the proposed biocomposites was monitored and analyzed through a model-based optimization approach using artificial neural network (ANN) method. The results of this study showed that the amount of water absorbed by different types of biocomposites increased with time according to Fick’s law. Non-hybrid flax and sisal fiber composites (UD and (0/90°)s oriented) had lower water absorption rates than the hybrid orientation. It was also observed that sisal fiber was most sensitive to water absorption than flax. A high correlation of experimental data with the model was revealed which denoted that the ANN learning process was perfectly performed. Therefore, it was inferred that the ANN approach can accurately predict biocomposites water absorption. [ABSTRACT FROM AUTHOR]

The goal of this study is to thoroughly comprehend the advantages of rattan (Calamus beccarii) as potential reinforcement in polymeric composites. The influence of various chemical treatments on thermal, morphological, mechanical and water absorption characteristics of natural rattan (RA) stem fiber were investigated. In this research, RA fiber surface was modified through different chemical treatments such as alkalization, bleaching, and benzoylation. The presence of voids and rough surfaces was investigated on SEM micrographs which are due to removal of lignin, wax, and oils from the fiber surface to a large extent. The results obtained from Fourier transform infrared may indicate the presence of cellulose, hemicellulose, and lignin compounds in the case of untreated and treated RA fiber. The increase in tensile strength and Young’s modulus confirms improvement in the mechanical properties of the RA fiber after chemical treatment. It was observed that alkali-treated RA fibers exhibit highest mechanical properties (295.28 MPa tensile strength, 8.23 GPa Young’s modulus). Also, X-ray diffraction analysis gives a higher crystallinity index (62.50%) for treated RA fiber. Thermogravimetric analysis confirms that there was an increase in the thermal stability of the fiber after chemical treatment. Overall results confirm that the RA fiber is appropriate for use as a reinforcing phase in composite materials for prospective engineering semi-structural applications such as roofing sheets, bricks, door panels, furniture panels, interior paneling, storage tanks, and pipelines. [ABSTRACT FROM AUTHOR]

Artificial neural networks (ANN) and response surface method (RSM) modeling were used to study the effect of water absorption on the behavior of jute (JF/epoxy) and sisal (SF/epoxy) biocomposite. The specimens were laminated with short fibers of different lengths (5 mm, 10 mm, and 15 mm) of jute and sisal until saturation lasted about 25 days. The kinetic behavior of water uptake was recorded and then compared to the curves predicted by the two models. The results showed that the water absorption of the jute and sisal biocomposites was fairly lower for the 5 mm length compared to the 10 mm and 15 mm lengths. The optimized solution is attained with 1.00 desirability for 14.73 mm fiber length and 482.85 h immersion time. The RSM model error percentages were higher than the ANN model indicating better accuracy in predicting the water uptake of biocomposites by the ANN model compared to RSM. The results of this investigation offer benefits for the application of jute and sisal fiber biocomposites at the elaboration and application stage; it is easy for engineers to identify the swelling factor of these biocomposites without the need for experiments, thus avoiding costs and time. [ABSTRACT FROM AUTHOR]

This research is manufactured composite materials from waste poly (ethylene terephthalate) reinforced with glass fiber and filled with waste window glass powder for tile application. The composite samples were prepared by the melt-mixing method followed by compression molding. The mechanical, thermal, and physical properties are investigated. To do this Charpy impact and Rockwell hardness testing machines, DSC, and Thermogravimetric analysis instruments were used. For this, it was prepared eleven samples by varying the glass fiber weight percentage from 0 to 10, matrix weight percentage from 70 to 85, and glass powder filler weight percentage from 5 to 20. The maximum impact strength (5.11 J/cm2 ) is recorded at 10% weight of glass fiber, 85% weight of PET matrix, and 5% weight of window glass filler. The maximum Rockwell hardness (184.2HR) and the minimum water absorption (0.048%) are also recorded at 0 weight % of glass fiber, 80 weight % of poly(ethylene terephthalate), PET, matrix, and 20 weight% of window glass filler. It can be concluded that the impact strength increased with increased weight % of glass fiber and decreased with increased window glass filler. The Rockwell hardness increased, and the water absorption decreased with increased weight % of window glass filler. [ABSTRACT FROM AUTHOR]

The present article attempts to study absorption properties of bio-composites reinforced with date palm fibers. The effect of fiber loading on water absorption at room temperature 25°C was investigated. The weight gain was measured of bio-composites immersed in distilled water, seawater and rainwater, for more than 670 hours, until reaching the saturation with a measurement interval between 24 and 48 hours. To understand absorption phenomenon, scanning electron microscopy was used. Porosity rate was determined using image J software. It was noted the water absorption rate of the bio composites reached 16.20%, 16.33%, 21.94%, 41.99% for seawater, 16.41%, 16.52%, 20.84%, 30.08% for distilled water, and 14.00%, 14.04%, 19.30%, 36.94% for rainwater, respectively. The absorption increases when increasing fiber content. The diffusion coefficient of bio-composites has minimum and maximum values of about 1.94 × 10−6mm2/s and 3.99 × 10−6mm2/s, respectively. Palm fibers are highly porous. The porosity value was higher than 51%. To predict the absorption rate, artificial neural network method was used. The ANN models obtained are very well correlated with the experimental data where the values of the correlation coefficient of the datasets are all beyond 0.99 and the average error value was estimated at 3 × 10−5. [ABSTRACT FROM AUTHOR]