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Carbon fiber reinforced plastics (CFRP) with the matrix of thermoplastic resin called as carbon fiber reinforced thermoplastics (CFRTPs) has been widely used in the industrial fields. Recently, a thermoplastic epoxy resin (TP-EP resin) has been developed as the matrix of CFRTP and carbon fiber reinforced TP-EP strands (CF/TP strands) molded by pultrusion method began to be used as tension rods for infrastructure under water absorption. On the other hand, an accelerated testing methodology (ATM) for predicting statistically long-term creep and fatigue strengths of CFRP was established by the authors. This study examines the prediction of statistical life time for these developed CF/TP strands at creep and fatigue tension loadings under the wet condition of water absorption with comparison to similar prediction under a dry condition by using our developed ATM. First, the static, creep, and fatigue tensile strengths of CF/TP strands were measured statistically at various constant temperatures under wet and dry conditions. The statistical long-term creep and fatigue tensile strengths for CF/TP strands under wet and dry conditions are predicted by substituting the measured data into the formulations of these strengths on our developed ATM. Finally, the influences of water absorption on the statistical long-term creep and fatigue strengths of CF/TP strands are cleared. In particular, the degradation of relaxation modulus of matrix TP-EP resin with increasing of elapsed time is accelerated with the water absorption, and the degradation of creep strength of CF/TP strand with increasing of elapsed time is also accelerated with the water absorption in the similar manner of matrix resin. On the other hand, the fatigue strength of CF/TP strand decreases scarcely with water absorption although this fatigue strength depends remarkably on the number of cycles to failure.

Enormous amounts of plastic wastes are generated worldwide and the approaches related to plastic recycling or reusing have become the research focus in the field of composite materials. In this study, green composites were prepared via melt-blending method using high-density polyethylene (HDPE) sourced from plastic bags as a matrix and sugarcane bagasse (SCB) fiber as reinforcing filler. The effects of fiber loading (5, 10 and 15 wt%) and fiber modification on the mechanical and dimensional stability (weight gain by water absorption) properties of the green composites were investigated. Results showed that the inclusion of SCB fiber into recycled HDPE matrix increased the composite stiffness but decreased the mechanical strength and resistance to water absorption. With the fiber modification through alkali treatment, the mechanical strength was remarkably improved, and the modulus and water absorption of the composites were found to be reduced. From the finding, it can be concluded that the prepared green composites free of coupling agent could add value to the plastic and agricultural wastes, and serve a potential candidate to replace some conventional petroleum-based composites.

The main purpose of this work is to investigate the effect of benzoyl treatment on the performance of sugar palm/kenaf fiber-reinforced polypropylene hybrid composites. Water absorption tests were carried out to confirm the effect of benzoylation treatment toward fabricating a more hydrophobic behavior of the hybrid composites. Both treated and untreated composites that have 10 wt.% of fiber loading with three different fiber ratios between sugar palm and kenaf (7:3, 5:5, 3:7) were analyzed. Physical and mechanical properties such as tensile, flexural, and impact strength were determined from this study. Morphological properties were obtained using scanning electron microscopy (SEM). It was found that the tensile strength of sugar palm/kenaf-reinforced polypropylene hybrid composites was improved with the treatment of benzoyl with a value of 19.41 MPa. In addition, hybrid composite with treated sugar palm and kenaf fiber T-SP3K7 recorded the highest impact and flexural strength of 19.4 MPa and 18.4 MPa, respectively. In addition, SEM demonstrated that surface treatment enhanced the mechanical properties of the hybrid composites. Overall, it can be suggested that benzoyl-treated composites with a higher volume of kenaf fiber than sugar palm fiber will improve the mechanical characteristics of the hybrid composites.

The composite materials are present in nature since the prehistoric era. Applications of fiber-based composite materials are increasing day by day in our society to overcome the raised environmental and economic concerns. Hence, waste fiber can be utilized as the best resource to develop composites. The present study deals with the impact of hybridization on the mechanical, thermal, and water absorption behavior of hair and coir fiber-based hybrid composites. The compression molding technique was used to develop the hybrid composites with fixed fiber content (15 wt.%) and was also varied the relative weight percentage of hair and coir fibers [(100% HF), (75% HF/25% CF), (50% HF/50% CF), (25% HF/75% CF) and (100% CF)] in reinforcing phase with HDPE composites S1, S2, S3, S4, and S5, respectively. The composite S2 was achieved superior mechanical attributes as compared to other hybrid/non-hybrid composites. The composite S2 was improved the tensile strength 5% and 35.2% more in comparison to composites S1 and S5, respectively. The thermal behavior (TGA, DTG, and DTA) was also influenced by the blending ratio of fibers of composites. The 5% and 50% weight losses of composite S2 were observed at higher temperature 343.8°C and 465.8°C as compare to other composites, which showed the thermal stability of composites S2. SEM analysis was used to investigate the strength of the fiber-matrix interface, which was shown a significant connection between mechanical and thermal behaviors. The crystallinity of hybrid and non-hybrid composites was examined by using the X-ray diffraction (XRD) analyzer and composite S2 was achieved 326 × 10−9 m crystal size at 21.053° peak position with wavelength 1.5406 × 10−10 m for Cu. The water absorption test was used to examine the moisture resistivity of composite materials, which was helpful to increase the applications of materials in humid areas.

The present study aims to investigate the water absorption property and its effect on the mechanical properties (i.e. tensile, flexural, and impact) of bionanocomposites. The epoxy-based bionanocomposites were prepared by reinforcing the epoxy with 1, 2, 3, 4, and 5 wt% of nanocellulose using in situ polymerization method. The maximum water uptake by bionanocomposites was measured; however, the water absorption behavior was not found in accordance with Fickian’s diffusion model. In the present study, very low water absorption in the range of 0.17–0.34% was offered by bionanocomposites. The results obtained from the present experimental study suggested that there were a maximum degradation of 14.96% in tensile strength, 26.44% in flexural strength, and 55.66% in impact strength for bionanocomposites reinforced with 5 wt% of nanocellulose by water uptake.

This paper presents the energy analysis of a triple effect absorption compression (hybrid) cycle employing ammonia water as working fluid. The performance parameters such as cooling capacity and coefficient of performance of the hybrid cycle is analyzed by varying the temperature of evaporator from −10 °C to 10 °C, absorber and condenser temperatures in first stage from 25 °C to 45 °C, degassing width in both the stages from 0.02 to 0.12 and is compared with the conventional triple effect absorption cycle. The results of the analysis show that the maximum cooling capacity attained in the hybrid cycle is 472.3 kW, at 10 °C evaporator temperature and first stage degassing width of 0.12. The coefficient of performance of the hybrid cycle is about 30 to 65% more than the coefficient of performance of conventional triple effect cycle.

Background: A historical turning point occurred in the treatment of diarrhea when it was discovered that glucose could enhance intestinal sodium and water absorption. Adding glucose to salt water (oral rehydration solution, ORS) more efficiently replaced intestinal water and salt losses. Aim: Provide a novel hypothesis to explain why mainstream use of ORS has been strongly recommended, but weakly adopted. Methods: Traditional (absorptive) and novel (secretory) physiological functions of glucose in an ORS were reviewed. Results: Small amounts of glucose can stimulate both intestinal absorption and secretion. Glucose can exacerbate a net secretory state and may aggravate pathogen-induced diarrhea, particularly for pathogens that affect glucose transport. Conclusion: A hypothesis is made to explain why glucose-based ORS does not appreciably reduce diarrheal stool volume and why modern food science initiatives should focus on ORS formulations that replace water and electrolytes while also reducing stool volume and duration of diarrhea.

Curcumin (Cur) is an active ingredient of Curcuma longa. Cur has many pharmacological effects, such as anti-inflammation, anti-oxidation, anticoagulation, hypolipidemic, anti-angiogenesis and anti-cancer. An injectable curcumin loaded chitosan/hydroxyapatite bone cement (Cur-CS/HA) was prepared as a bone scaffold and drug delivery. Tween 20, a nonionic surfactant, was incorporated into the cement to improve the solubility of curcumin. Four types of Cur-CS/HA (Group0, Group1, Group5 and Group10) were prepared with different Tween 20 ratios (0, 1, 5 and 10%, respectively). The samples were characterized by infrared spectroscopy (IR), X-ray diffraction (XRD) and scanning electron microscope (SEM). Compression tests were carried out to evaluate the strength of the scaffolds. In addition, the inhibition assay was carried out on MG63 cells with the extracts of drug loaded materials. The results showed that Cur had an effect on the setting time (p

Psyllium is a natural fibre with high water absorption capacity and proved nutritional advantages. The aim of this study was to evaluate the potential of psyllium as a fat replacer in sugar-snap cookies. Elaborations were made with wheat flour or maize flour by maintaining the original recipe or replacing the fat by a paste made with different proportion of psyllium and water. Cookies dough rheology and final cookies properties were evaluated. An acceptability test was also carried out. The replacement of fat decreased the values of G′, G″ and G*, but increased tg delta to a greater extent in cookies with gluten. Cookies diameter and spread factor decreased and increased both cookies hardness and moisture content. Fat replacement increase L* value of cookies. Variation of the water content did not influence in the rheology of the dough and in the characteristics of gluten-free cookies, but wheat cookies had smaller spread ratio and decreasing hardness for increasing amount of water. Final cookies had low acceptability and this result was more evident in gluten-free cookies. Considering this result, it is difficult to use psyllium as a total fat substitute in this type of product.

Recently, researchers and scientists are trying to overcome the environmental burden by using biocomposites in engineering applications as far as possible. The main source of biocomposites is cellulosic fibres which is a class of natural fibres. Instead of many advantages of cellulosic fibres, they and their polymer composites suffer from some limitations as well. The environmental conditions are one of the most important issues to degradation behavior of the cellulosic fibres polymer composites (CFPCs). Among the environmental conditions, water absorption is an important ground to degradation in the mechanical performance of the CFPCs, which resists them to be used in outdoor applications. Several studies have been presented on water absorption characteristics of cellulosic fibres and its polymer-based biocomposites. Further, the consequence of water uptake on the mechanical performance of biocomposites was also reported in many studies. In most of the cases, a negative effect of water absorption was observed, whereas in a few cases a positive effect was also seen. In the present study, mechanics and kinetics of water absorption for CFPCs are discussed. Further, a detailed literature review on water absorption of cellulosic fibres and their different types of polymer-based biocomposites has also been carried out. Furthermore, studies reported on the effect of water absorption on the mechanical properties were also systematically presented. Moreover, all the possible remedies to lower the water absorption capacity were also discussed in the present review paper.

A novel epoxy-based composites were fabricated by reinforcing pineapple/flax (PF) fibers and peanut oil cake (PCF) filler using the hand layup cum compression moulding technique and investigated its mechanical, water absorption and wear properties as a function of wt.% of PF fibers (20–40 wt.%) and PCF (1–3 wt.%). The XRD and FTIR results proved the presence of lignocellulosic nature in PCF. Mechanical test results showed significant enhancement in the properties after the addition of PCF. The maximum tensile, flexural and impact properties of 37. 89 MPa, 70.28 MPa and 96.99 J/m were observed in the composites having 20 wt.% of PF and 2 wt.% of PCF. Taguchi based optimization observed a lower specific wear rate (SWR) with 2 wt.% PCF/20 wt.% PF/5 N load and 1500 m sliding distance (SD) combination. The ANOVA results proved the significance of PCF, PF fiber, sliding distance, and load for SWR in this experimentation. The Taguchi optimized results observed a lower coefficient of friction (COF) in 2 wt.% PCF/20 wt.% PF/5N load/500 m SD combination. SEM results displayed surface deformations in the wear-tested composites.

The influence of fiber loading and chemical treatment of Urena lobata natural fiber loading (5, 10, 15, 20, 25, 30, and 35 wt%) on the physical, wear, and thermal stability of polypropylene-based composites was investigated. Urena lobata fibers were treated with 6 wt% NaOH solution. Both the untreated and treated Urena lobata/polypropylene composites were produced by compression molding. The physical (density and water absorption) and abrasion properties of the composites were then evaluated. Thereafter, the thermal stability of the fibers and composites were analyzed. The alkaline-treated Urena lobata fiber-reinforced polypropylene composites showed improvement in the density (1.04–1.74 g/cm3) and wear resistance (19.57–26.17 mm3) than the untreated Urena lobata fiber/polypropylene composites. However, the treated Urena lobata fiber/polypropylene composites absorbed more water than the untreated Urena lobata fiber/polypropylene composites. Then the treated fiber composites were more thermally stable than the untreated fiber composites due to enhanced fiber–matrix adhesion obtained by alkaline treatment of the fibers.

In this paper, the statistical analyses of the ammonia-water absorption refrigerant system (ARS) are presented. For this purpose, different surface response methods, including the Central composite design (CCD) and Box- Behnken design (BBD), have been studied and compared first to obtain the best response. An attempt is made to study the effect of some factors (mass flow rate, isentropic efficiency of pump, pressure ratio, maximum pressure of cycle, concentration difference of strong and weak solution, concentration of strong solution and effectiveness factor of heat exchanger and pure ammonia concentration) on the system’s response. Based on the design of experiment analysis, regression models are presented to quantify the effects of these parameters on coefficient of performance (COP) and cooling load of the ammonia-water absorption refrigerant cycle. The proposed correlations obtained by the analysis have remarkably satisfactory performance for all simulation data. The error analysis is applied to find the maximum error of 0.482% in numerical computations for ARS by CCD method in midpoint values of parameters.

The present study aims to investigate the influence of food waste (citrus limetta peel) filler size on the thermal and mechanical behaviour of epoxy resin based composites. The present research work was undertaken with three different categories of fillers i.e. (i) (100–250) µm and ii) (350–500) µm and iii) (650–800) µm in 15 wt.%. The epoxy resin modified with citrus limetta peel (CLP) fillers was exposed to water soaking for diverse time durations of 24 hrs, 48 hrs, 72 hrs, 96 hrs and 120 hrs. Mechanical and thermal properties of modified epoxy resin have been evaluated. A morphological analysis of the fractured surfaces of different composite specimens was also performed. The results revealed that the composites having coarse CLP fillers showed maximum water absorption. The mechanical characterization results revealed that the tensile and flexural strength were reduced in comparison to neat epoxy (NE). The impact strength of the developed composites increased for fine CLP fillers based composites. Overall, it was established that there is a significant effect of variation in filler size on developed composites and composites with fine CLP fillers gave best results compared to medium and coarse fillers based composites.

The objectives were to synthesize urethane grafted nano-apatite in shortest possible time duration using the microwave irradiation method and to utilize them for synthesis of experimental dental adhesives. The structural, morphological, thermal, and mechanical behavior of synthesized grafted nano-apatite were investigated. Then, these grafted nano-apatite particles were incorporated in various concentrations that is, 5wt.%, 10wt.%, and 15wt.% into dimethacrylate resins to develop bioactive adhesives. The weight measurement analysis in deionized water and phosphate buffer saline, Knoop micro-hardness, and degree of conversion were evaluated. The bacterial adhesion was investigated with Streptococcus mutans at 6h, 24h, and 48h. Statistical analysis was conducted using one-way ANOVA. The urethane dimethacrylate was successfully grafted on the nano-apatite surface and spectroscopic analysis confirmed the presence of urethane and phosphate peaks. An inverse relationship was found in both media between the concentration of grafted fillers and weight loss. No significant difference was observed in the micro-hardness and degree of conversion among the groups, whereby the degree of conversion for all groups was in the range of 83% to 86%. The mean number of bacterial colonies was significantly lower in the 15wt.% group compared to 5wt.% and 10wt.%. The grafted nano-apatite presented favorable results for adhesive resin incorporation, where 15wt.% group comparatively showed superior results than other groups.

Demand for natural fibers reinforced composites is growing as an alternative to synthetic fiber reinforced plastic composites. However, poor compatibility between natural fiber and matrix has limited its development. Therefore, it is necessary to improve their interfacial adhesion to improve the comprehensive properties of composites. In this work, sisal fibers were subjected to an alkali/polyvinyl alcohol coating treatment by an ultrasonic impregnation method, and the sisal/high-density polyethylene composite was prepared by a twin-screw extruder. The Fourier transform infrared spectroscopy was used to characterize the modification effect of sisal fiber. The surface morphology of sisal fiber and the interfacial morphology of sisal/high-density polyethylene composites were observed. The mechanical properties and water absorption of sisal/ high-density polyethylene composites were also studied. The results show that alkali/polyvinyl alcohol coating compound treatment can effectively improve the interfacial adhesion between sisal fiber and high-density polyethylene, improve the mechanical properties of composite, and reduce water absorption. Alkali/polyvinyl alcohol coating compound treatment is a very environment-friendly, cost-effective fiber modification method when compared with traditional modification methods. It is helpful for the development and application of natural fibers reinforced composites.

To overcome high water absorption of inorganic metal salts and their poor compatibility with resin, acetylacetone metal salts (M(acac) n) were selected as the catalysts of benzoxazine resin. Their effects on the catalytic activity, structure, and thermal stability of polybenzoxazine had been estimated by dynamic differential scanning calorimetry, in situ Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and thermal gravimetric analyzer. The results revealed that M(acac) n of iron (Fe3+), cobalt (Co3+ and Co2+), and copper (Cu2+) exhibited high catalytic activity and reduced evidently activation energy, especially acetylacetone iron salt. The addition of M(acac) n was beneficial to the formation of Ph–N–Ph structure, which was easy to form a denser carbon layer during thermal degradation, prevented heat transfer and further decomposition of the resin, and finally led to the increase of carbon residue at high temperature.

In this study, bamboo and glass fibers were successfully added into bisphenol A–aniline-based benzoxazine resin by hot pressing method. The effect of water absorption on the mechanical properties of the neat benzoxazine and its composites was studied. The composites prepared in this study has been proved to exhibit better water resistance than some conventional natural fiber/polymer composites due to good hydrophobicity of the benzoxazine matrix. From the mechanical tests, the tensile performance of both neat benzoxazine and the composites degraded seriously after prolonged immersion in water. However, neat benzoxazine and the composites maintained relatively higher residual flexural properties (residual mechanical properties refer to the ratio of strength and modulus of the saturated samples to that of the nonaged samples) after 20 days of water immersion. The effect of water molecules on the fracture surface morphologies of the composites was studied using a scanning electron microscope (SEM). The SEM images showed that the interfacial bonding between fibers and the matrix degraded seriously due to the attack of water.

Recycled bamboo fiber-reinforced chemically functionalized ethylene propylene rubber (R-BMBF/CF-EPR) composites have been developed by extrusion and injection molding by Palsule process without any fiber treatment and without compatibilizer. Scanning electron microscopy (SEM) shows good R-BMBF/CF-EPR interfacial adhesion in the composites, and Fourier transform infrared (FTIR) confirms that esterification and the hydrogen bonding between functional groups of CF-EPR and of R-BMBF impart this interfacial adhesion. Mechanical, dynamic mechanical, and thermal properties and the effect of water absorption on tensile properties of the composites have been evaluated. Tensile properties of the 15/85, 25/75, and 35/65 R-BMBF/CF-EPR composites are higher than those of CF-EPR and increase with increasing R-BMBF in the composites. Storage modulus and loss modulus of the composites increase with increasing fiber contents in them but decrease with increasing temperature. Water-absorbed wet composites show thickness swelling and reduced tensile properties relative to the respective dry composites but higher tensile properties than the dry CF-EPR. Thermal stability and degradation of the composites is also reported.

Epoxy resin and their particulate composites are widely used in different industries, as aeronautical, automotive, microelectronics and coatings. The water absorption can deteriorate the properties on these materials when they are used in service. Many factors influence in water absorption process, as the quantity of hydroxyls groups, the glass transition temperature of the resin or the presence of a dispersed second phase. Thus, the objective of this work is to determine the dielectric behavior of BaTiO3–epoxy composites in different humid environments (controlled moisture of 80, 50 and 30%) and at room temperature. Results of pure resin samples show that dielectric permittivity increases with the percentage of absorbed water and that this increase is greater for the samples exposed to more humid environments. Interestingly, the addition of ceramic particles not only increases the composite dielectric properties but also reduces the water absorption in all the cases.

This study investigates the biosynthesis of microbial cellulose–electrospun nano-fibrous membrane hybrid nano-fabric via the use of a modified bioreactor. Microbial cellulose is known for its high liquid absorbency and hygienic nature. Electrospun nano-fibrous membranes, on the other hand, exhibit excessive surface hydrophobicity in typical conditions. As such, this research intends to improve the hydrophilic property of electrospun membranes through in situ self-assembly of microbial cellulose nano-fibrils on membrane’s surface. Scanning electron microscopy showed successful growth of microbial cellulose nano-fibrils on the surface and within the structure of electrospun membranes which could possibly contribute toward improved tensile properties. Some functional properties of hybrid nano-fabric, including water absorbency, drying time, and amount of vertical wicking, were determined and compared with pure electrospun membrane samples. Results showed that water absorbency, wicking ability, and drying time increased, as a result of microbial cellulose reinforcement. The average increase in water absorption capability and water-holding time was 72.8 and 32.65%, respectively, whereas wicking ability increased up to 16.5%. In conclusion, the results demonstrate that microbial cellulose contribution has importance for hybrid nano-fabric in terms of key material characteristics that are appropriate for wound dressing and related applications.

This study investigates the effect of the constituents and temperature of a coagulation bath on the morphology and water absorption behavior of a skin–core filament, which has potential application in the field of controlled drug release, based on biomedical polyurethane (BPU) and native silk fibroin microparticles (NSFPs). BPU solution and BPU/NSFP blend solution were extruded from the cortex and core channel of a coaxial double injector into a coagulation bath with different constituents and at different temperatures to form filaments. Scanning electron microscopy analysis of the skin–core filament prepared by wet-spinning revealed that the addition of ethanol decreased the exchange speed between the solvent and non-solvent and led to the formation of micropores on the surface. Meanwhile, the interface between the cortex and core became pronounced and the water absorption capability of the filament decreased with increasing ethanol concentration in the coagulation bath. The high temperature of the coagulation bath also improved the exchange speed between the solvent and non-solvent; however, its effect on the morphology of the filament was weak. Thus, a skin–core filament with different morphologies and water absorption behaviors was fabricated by controlling the constituents and temperature of the coagulation bath during the wet-spinning process. This skin–core filament has potential applications in controlled drug release.

The present work aims to study the moisture uptake and thickness swelling behaviour and its effect on tensile and flexural properties of Luffa cylindrica epoxy composite. Characterizations of the l...

The present work deals with the effect of various treatments on the mechanical properties and water absorption of wheat straw (WS)-reinforced polystyrene (PS) composites. Four different surface treatments of the filler, that is, alkali treatment of WS by 20% sodium hydroxide (NaOH) solution, maleic anhydride (MA) treatment of WS by 2% MA solution, WS treatment with 1% silane (ATS) and WS treatment with 20% NaOH and 1% silane, with 5–25% filler loading were carried out. There is an enhancement in tensile modulus, impact strength and water absorption and a decrease in tensile strength of WS fiber-filled PS composite with an enhancement in fiber loading when it is treated with 20% NaOH, 2% MA, and 1% silane. There is an enhancement in tensile strength, tensile modulus, Izod impact strength, and water absorption value when the WS fiber is treated with 20% NaOH and 1% silane, with an enhancement in fiber loading. Treatment with 20% NaOH and 1% silane exhibits better results as compared to the rest of the surface treatments.

The effects of wheat flour substitution by sweet potato powder on rheological parameters of wheat dough and physical parameters of cookies and crackers were analyzed. Wheat flour was substituted with sweet potato powder at level 2.5%, 5%, 7.5%, and 10%. Sweet potato powder was characterized by high water holding capacity (9.00 g/g) and swelling capacity (8.16 cm3/g). The addition of sweet potato powder significantly changed the rheological properties of wheat dough (water absorption and mixing tolerance index were increased, dough stability was reduced, and dough development time was prolonged). It was also found that volumes of cookies and crackers were decreased, and spread ratios were increased with the addition of sweet potato powder. Lightness of baked products decreased and yellowness increased with the addition of sweet potato powder. Incorporation of sweet potato powder significantly decreased the hardness of cookies and crackers. Sensory evaluation showed that the most acceptable cookies and crackers were the ones obtained after the addition of sweet potato powder at level 2.5% and 7.5%, respectively.

The objective of this work is to access the possibility of reinforcement of a new and almost inexpensive natural fiber in epoxy composites. In this study, epoxy-based composites reinforced with African teff straw ( Eragrostis tef) have been fabricated using simple hand layup technique with different fiber loadings varying from 5% to 25%. The fiber surface is treated with 5% alkali, 10% alkali, silane, and acetic anhydride to improve the interaction between fiber and matrix. The mechanical, morphological, water absorption, and thermal characteristics of both the untreated and the treated composites have been studied to analyze the properties and effect of surface treatment on prepared composites. Water diffusion mechanism has also been studied. The effect of various treatment methodologies has been compared to obtain superior quality composites; 15% fiber loading and silane treatment have improved the tensile strength and flexural strength by 40% and 25%, respectively, while 5% alkali-treated composites increased tensile strength by 12% as compared to neat epoxy resin.

In this work, the effect of water absorption and stacking sequences on the mechanical properties (i.e. impact, tensile and flexural) of hybrid sisal/glass polyester composites has been studied. Each composite laminate is prepared by the hand lay-up technique followed by static compression using about 20 wt% of fibre content. Different stacking sequences are obtained by changing the position and number of glass layers keeping a total of eight plies in each composite. Water absorption behaviour is investigated by soaking the composite specimens in the distilled water until saturation and its characteristics such as sorption, diffusion and permeability coefficient are measured. The obtained results suggested that the mechanical and water resistance properties of sisal composites are considerably enhanced by the incorporation of glass fibre. There is 23%, 29% and 46% improvement in tensile strength, flexural strength and impact strength respectively in hybrid composites than that of sisal composite. However, the effect of water absorption showed a significant reduction in the mechanical performance of all the composites. Morphological analysis by scanning electron microscope has been also performed to support the statement as weakening of fibre–matrix interfacial bonding by water absorption.

The abrasive wear performance of glass–polyamide fibers/epoxy composites was experimentally studied using a pin-on-disc wear tester at different applied normal loads. Specimens were fabricated in inter-ply configuration using the hand layup technique. Specimens were subjected to distilled water and sea water immersion at room temperature for 200 days. The effects of the reinforcement hybridization, stacking sequence, and relative fiber amounts on the wear behavior of dry and wet specimens were discussed. Temperature rise at the specimen pin–disc interface has been measured. The morphologies of the worn surfaces were investigated with scanning electron microscopy (SEM). Results showed that distilled water and sea water uptake of glass/epoxy composite is 2.5 and 2 times those of polyamide/epoxy counterparts. Correction factor decreases the diffusion coefficient by about 24% and 26% for, respectively, polyamide/epoxy and glass/epoxy composites. Hybridizing glass fiber composite with polyamide fiber could reduce the specimen’s weight loss during wear test for dry and wet specimens. Water uptake induces a significant decrease in wear resistance of the studied composites. Stacking sequence has a slight effect on wear resistance, while relative fiber amounts have a noticeable effect. The maximum temperature at the specimen pin–disc interface (21.5°C) was noticed for glass/epoxy composite under applied load of 10 N. As the applied load and the sliding time increase, the wear resistance of the composites decreases but the temperature at the specimen pin–disc interface increases. SEM observations show debonding, cracks, fiber fracture, and debris formation.

Rubberwood flour (RWF) was treated by alkaline, silane, and alkaline–silane, and consequently, reinforced recycled polypropylene (rPP) composites. The wood–plastic composites (WPCs) were prepared with 40 wt% RWF content using a twin-screw extruder, followed by compression molding. Silane treatment was applied at various concentrations and treatment times to evaluate the effect of treatment conditions on water absorption, mechanical properties, thermal properties, and morphological characterization of WPCs. The results indicated that alkaline–silane treatment of RWF exhibits higher properties in comparison to silane or alkaline only. In addition, silane concentrations significantly affected water absorption, mechanical strength, and hardness, while treatment times remained relatively unaffected by these properties. The best water resistance, mechanical strength, and hardness of WPCs were achieved by alkaline–silane treatment with 5% silane concentration for 2 h, which improved the interfacial adhesion of RWF and rPP as well as increased the crystallinity in the WPCs.

This paper represents the first effort aimed to study the interdependence of mercerization, moisture absorption and mechanical properties of sustainable Phoenix sp. fibre-reinforced epoxy composites fabricated by compression moulding technique. The investigation was carried out by varying the fibre length (10, 20 and 30 mm), fibre volume fraction (10%, 20%, 30%, 40% and 50%), concentration of sodium hydroxide for fibre treatment (5%, 10% and 15%) and immersion temperature (10℃, 30℃ and 60℃). The fibre–matrix interface and failure mechanism was studied by using scanning electron microscopy. The results revealed that the moisture absorption rate increased with the increase in fibre length, fibre volume fraction and immersion temperature result in loss of tensile and flexural properties. The moisture absorbed samples shows 15% and 7% drop in tensile and flexural strength, respectively. However, this loss was less in mercerized fibre-reinforced composites.

The main objective of the present paper is to study the water absorption of jute–glass–carbon-reinforced epoxy composites and its subsequent effect on the in-plane shear performance of these composites. The effects of the reinforcement hybridization, stacking sequence and relative fabric amounts on the shear behavior of dry and wet conditioned composite specimens are reported and discussed. Composites have been fabricated in inter-ply configuration using the hand lay-up process. The prepared specimens have been subjected to distilled water and sea water immersion at room temperature for 60 days. Results indicated that water uptake of jute-reinforced composite and its hybrids with glass and/or carbon follows Fickian-like behavior. Water uptake induces a significant decrease in the in-plane shear strength. Hybridizing jute fabric with glass and/or carbon fabrics improves the in-plane shear properties of both dry and wet specimens. The stacking sequence and relative fabric amounts have a noticeable effect on the studied shear properties. Also, the hybrid composite with jute as facings and glass as core, JGJ, offers the most balanced set of properties on a cost-effective basis compared to the other studied hybrids.

This research covers the preparation of poly(lactic acid) (PLA)/sugarcane leaves fibre (SLF) biofilms via a solvent-casting method. The results showed that the tensile strength and Young’s modulus of PLA/SLF biofilms increased with the increasing of SLF content. Nevertheless, the elongation at break showed an opposite trend as compared to tensile strength and Young’s modulus of biofilms. Moreover, water absorption properties of PLA/SLF biofilms increased with the increasing of SLF content. In contrast, the tensile strength and Young’s modulus of biofilms were enhanced after bleaching treatment with hydrogen peroxide on SLF, but the elongation at break and water absorption properties of bleached biofilms were reduced due to the improvement of filler–matrix adhesion in biofilms. The tensile and water properties were further discussed using B-factor and Fick’s law, respectively. Furthermore, the functional groups of unbleached and bleached SLF were characterized by Fourier transform infrared analysis.

The present study reveals the characterization of hybrid wood composites. The effect of hybridization of sal wood on the mechanical, thermal, and water absorption properties of mango wood reinforced epoxy polymer composite was studied. The wood composites were prepared by hand lay-up technique by maintaining a constant 33 wt% of total wood flour content with varying weight ratios. Mechanical properties such as tensile, flexural, and impact were investigated as per the ASTM standards. In addition, dynamic mechanical properties in terms of glass transition temperature [Formula: see text], storage modulus [Formula: see text], and damping (tanδ) were also studied. The degradation of wood composites with respect to temperature was analyzed by thermogravimetric analysis. Water absorption properties were carried out in terms of percentage of water absorption at saturation stage, and sorption, diffusion, and permeability coefficient. The results suggested that mechanical, thermal, and water resistance properties were significantly enhanced due to hybridization. Moreover, the best mechanical performance among all composites was seen for hybrid wood composite with equal proportion of mango and sal woods. The present prepared composites can be proposed for use in various industries such as automobile, building and construction, marine, packaging, and aerospace.

The hygroscopic nature of wood limits the use of wood thermoplastic composites (WTC) in outdoor industrial and domestic applications. To reduce this tendency, red balau saw dust was heat treated at 180 and 200°C for 1 h and compounded with Low Density Poly(ethylene) (LDPE) into 20 and 37 wt% and then molded into test specimens by injection molding. Samples were immersed in distilled water at room temperature for 4 months. Heat-treated wood composites showed remarkable water resistance relative to untreated ones. Wood composites made from wood treated at 180 and 200°C exhibited almost similar water absorption pattern. Reduced water absorption of heat-treated wood composites relative to untreated ones indicates that heat treatment has resulted in a degree of modification of the wood. Most of the composites displayed the Fickian mode of water absorption with n values close to 0.5. Also, the diffusion coefficient reduced with wood content in untreated wood composites due to interaction of water with the polar groups in wood through hydrogen bonding. Untreated wood composites exhibited poorer mechanical properties with water immersion as a result of degradation due to moisture. The mechanical properties of the heat-treated wood composites were not adversely affected with water absorption. Therefore, heat treatment can reduce the proneness to water absorption in WTCs and alleviate the detrimental effects on mechanical properties.

This paper addresses the effects of different stacking sequences and seawater on the buckling behavior of hybrid composite plates. For the buckling tests, 12-layered hybrid composite plates were produced using different combinations of carbon, E-glass and aramid fibers, with an epoxy resin system as the matrix (Araldite LY1564/Aradur 3486). The hybrid composite plates were designed at the symmetric orientation angles of [(0/90)3]s, [(30/−60)3]s, [(45/−45)3]s and an anti-symmetric orientation angle of [(0/90)3]2. The hybrid composite samples were divided into groups and were subjected to buckling tests after being kept in different settings for varying periods of time (room temperature for 90 days, Black Sea water for 90 days, Mediterranean Sea water for 90 days, Mediterranean Sea water for 150 days). In light of the data obtained from the tests, the buckling behaviors of the layered hybrid composite plates were examined. The highest critical buckling load occurred in the carbon/aramid/glass (CAG) hybrid samples with the stacking sequence of [(0/90)3]s, whereas the lowest critical buckling load occurred in the carbon/aramid/glass (CAG45) hybrid samples with the stacking sequence of [(45/−45)3]s. It was observed that the critical buckling loads of the samples immersed in seawater decreased when compared to the critical buckling loads of the samples kept at room temperature. It was also found that the critical buckling loads of the hybrid samples immersed in the Mediterranean Sea water, which has high salinity, were lower than the critical buckling loads of the hybrid samples immersed in the Black Sea water, which has lower salinity.

This study deals with the investigation of the mechanical and water absorption properties of jute fibre reinforced epoxy composites prepared by using hand layup method. The effects of fibre length (10, 20, 30 and 40 mm), fibre weight fraction (0%, 5%, 10%, 15%, 20% and 25%), concentration of NaOH treatment (5% and 10%) and nano-clay addition (1, 3, 5 and 7 wt%) on the aforementioned properties were determined. Morphological characterisation was performed for the tensile and flexural fractured surface of the specimens to study their microstructural failures. The results revealed that the composites reinforced with 5% of NaOH-treated fibre and 5 wt% of nano-clay exhibited higher tensile, flexural and impact strengths of 103.05 MPa, 162.8 MPa and 0.358 kJ/mm2 respectively, and lower water absorption rate. Moreover, the optimum fibre length and fibre weight fraction were found to be 30 mm and 20% respectively for better overall properties. These composites can be used for light and medium load applications.

Surface sensitive Fourier transform-infrared attenuated total reflectance (ATR) accessories using different crystals as well as incident beam angles were examined for the characterization of cotton fabric scouring. The extra sharp antisymmetric and symmetric C-H stretching peaks due to long chain alkyls at 2918 and 2849 cm−1 were observed in greige cotton fabrics with a tendency to be more profound with the ATR cell with bigger incident angles and a higher refractive index, due to less depth of penetration. Water absorption data and gas chromatography-mass spectrometry analyses indicated that these peaks were mostly caused by secondary added paraffin wax of higher linear alkanes (C22 to C30) and cotton wax of C16 and C18 fatty acids in free form. Absence of these peaks alone did not result in sufficient water absorption. No observation of carboxylate (COO−) peak at 1600 cm−1 together ensured a successful scouring. Presence of this weak peak can be further confirmed by the reversible shift between 1600 cm−1 and 1750 cm−1 of protonated carboxylic acids (COOH) under non-destructive and quick HCl or NH3 vapor exposures on cotton samples.

Wheat cultivars were treated by four different treatments and their flours were obtained after milling. The quality of the obtained wheat flours was determined using various quality parameters and it was observed that premilling treatments significantly affect the gluten content, wet and dry gluten yield, gluten index, and water absorption capacity of gluten, respectively. Acid-treated wheat flours of all the four wheat varieties (C-306, Raj-3765, PBW-343, and KW-11) showed lower gluten content and quality, whereas conditioning and yeast treatment improve gluten quality as well as its content. Flours obtained after premilling treatments were also utilized for noodle preparation and their sensory and quality parameters were also determined. Also, it was observed that yeast treatment and conditioning improved the noodle quality, whereas acid treatment deteriorates the noodle quality in comparison to tempering. The cultivar PBW-343 produced the best quality noodle among four wheat cultivars. In different milling treatments acid-treated flours of all cultivars showed lowest sensory and quality characteristics, while yeast treatment showed highest.

Tools abrasive wear due to sand particles has caused severe damage during oil and gas exploitation. The friction and wear behaviors of single quartz sand particle against N80 casing steel were investigated to estimate the particle transport resistance and particle abrasive wear behavior using a homemade tribometer in wellbore sand cleanout. Various measurements were conducted to research the impact factor of particle under different water processing condition, dry, short immersion, wet, influences of load and slide velocity. Experimental results indicated that particle-casing friction resistance is mainly formed due to plowing and adhesion effect. Casing transfer and plowing removal are two main damage forms. Particle real contact area increases noticeably after water absorption, which decreases the hertz contact stress and finally produces less plowing depth of casing steel and causes less damage. With load increasing, friction resistance and wear increase with addition of plowing depth. A simple particle-casing friction model was established considering the experimental contact behavior.

In the present work, a novel physical treatment (PLA coating) of sisal fibres and its influence on the water absorption, static and dynamic mechanical properties of its composites has been presented. The treated sisal fibres were used consisted of alkali treatment and PLA coating to fabricate its polyester-based composites by hand lay-up technique keeping constant fibres content as 20 wt.% . Water absorption analysis was carried out in terms of water uptake (%), and sorption, diffusion and permeability coefficient. In addition, static properties were examined in terms of tensile, flexural and impact test, and dynamic mechanical analysis was performed in terms of storage modulus [Formula: see text], loss modulus [Formula: see text], damping [Formula: see text] and glass transition temperature [Formula: see text]. It was reported that the PLA-coated sisal composites showed the best performance in water absorption, mechanical and dynamic mechanical properties than pure sisal and alkali-treated sisal composites. There were 33%, 49%, 48%, and 27% improvement in water resistance, tensile strength, flexural strength and impact strength, respectively, of PLA-coated sisal composites as compared to that of pure sisal composite.

The effect of water aging on the impact performance of glass (G)–polypropylene (P)-reinforced epoxy composites was investigated. Specimens were fabricated using the hand layup process with constant overall fiber volume fraction. Specimens were immersed in distilled water and seawater at room temperature, until reaching their water content saturation point. The dry and water-immersed specimens were subjected to edge-wise and flat-wise impact tests. Fractured surfaces were examined using scanning electron microscopy, SEM. The results showed that the impact performance of G-reinforced epoxy composite has been enhanced through hybridizing it with P-fiber but water uptake has been increased. Water uptake reduces the impact strength of all tested specimens. Composites exposed to seawater absorb less water than those exposed to distilled water. The water absorption percentage and impact performance can be effectively controlled by changing the hybrid configuration, plies stacking sequence and P/G fiber ratio.

This article studies the hygrothermal behavior of E-glass fiber-reinforced polyester composites containing filler additives. Three different cases of a material exposed to water are investigated at two various temperatures: 45℃ and 65℃. First, both lateral sides are exposed to water at the same temperature (symmetric absorption). Second, one side is exposed to water at a certain temperature and the other side is exposed to ambient air (dissymmetric absorption I). Third, both lateral sides are exposed to water at varied temperatures (dissymmetric absorption II). The kinetics of water absorption follows the Fick’s second law. The water concentration is higher on the surface of the material and it decreases continuously toward the core of the model. The increase in the temperature and the higher level of additives raise the absorbed moisture and the diffusion coefficient. The software “Abaqus” is used to simulate the water diffusion through the material. The comparison between the experimental and numerical results shows that the model can predict the hygrothermal behavior of the polyester/glass fiber in symmetric and dissymmetric absorption.

This study investigated the influence of pregelatinized high-amylose maize starch and chilling treatment on the physical and textural properties of canned rice noodles thermally processed in a retort. Rice noodles were prepared from rice flour partially substituted with pregelatinized high-amylose maize starch (Hylon VII™) in the ratios 0, 5, 10, and 15% (wt/wt). High-amylose maize starch improved the texture and brightness of fresh (not retorted) noodles. Chilling treatment led to significant (P ≤ 0.05) improvement in the texture of fresh noodles at all levels of substitution with high-amylose starch. The highest hardness was recorded at 15% amylose level in chilled nonretorted noodles. Retort processing induced a major loss of quality through water absorption, retort cooking loss, decreased noodle hardness, and lightness. However, the results showed that amylose and chilling treatment positively reduced the impact of retorting. For each level of amylose substitution, a low retort cooking loss and increased noodle hardness were associated with a chilling treatment. For both chilled and nonchilled noodles, retort cooking loss and hardness increased with increasing levels of amylose substitution.

This work deals with the investigation of mechanical properties and water absorption behavior of Calotropis Gigantea fiber reinforced epoxy composites prepared by using compression molding technique. The experiments were carried out by varying fiber length (10, 20, and 30 mm) and volume fraction (0, 5, 10, 15, 20, 25, and 30%). In addition to this, the water absorption behavior was analyzed at different climatic temperatures of 10℃, 40℃, and 70℃. The composites reinforced with 25% in volume of Calotropis Gigantea fiber showed better tensile, flexural, and impact properties. The hardness value and water absorption rate are higher for composites reinforced with 30% in volume of 30-mm Calotropis Gigantea fibers. Moreover, by increasing the bath temperature, the water absorption rate associated to this class of composite increases.

The lifespan and economic viability of tidal energy devices are constrained, in part, by the complex degradation of the tidal turbine blade materials due to prolonged immersion in a hostile sub-sea environment. Seawater penetration is a significant degradation mechanism in composite materials. This work aims to investigate the influence of microstructure and hydrostatic pressure on water absorption in four polymer composites which are candidate materials for use in tidal energy devices. These materials are: a glass fibre powder epoxy, a carbon fibre powder epoxy, glass fibre Ampreg epoxy and a chopped fibre glass fibre Polyether Ether Ketone. X-ray computed tomography is used to characterise the voids, resin-rich areas and other manufacturing defects present in each material. These defects are known to significantly alter the rate of moisture diffusion, as well as the total uptake of water at saturation. The samples are then exposed to accelerated water aging and hydrostatic pressurisation in order to simulate a range of expected sub-sea operating conditions. The material micro-structure, the matrix material and pressurisation level are shown to strongly influence both the moisture absorption rate and total water uptake. Significant volumetric changes are also noted for all samples, both during and after aging. X-ray computed tomography scans of specimens also provide a unique insight into the role of voids in storing water once a material has reached saturation. The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This research was partly funded by Science Foundation Ireland (SFI) through the Marine and Renewable Energy Ireland (MaREI) research centre (Grant no. 12/RC/2302), the Irish Research Council (IRC) through the employment-based postgraduate scheme and by MARINCOMP – Novel Composite Materials and Processes for Marine Renewable Energy (EU FP7 – People, Industry Academia Partnerships and Pathways (IAPP), reference: 612531). The last author would like to acknowledge the support of Science Foundation Ireland through the Career Development Award programme (Grant No. 13/CDA/2200). peer-reviewed

Chemical modification of fiber surfaces can increase wettability of composites reinforced by vegetal fibers and, consequently, the dispersion of the fiber in the matrix and mechanical properties can be improved. Although there are some studies about agents for chemical modifications of vegetal fiber surfaces, there are few data and discussion about the usage of lignin. In the present work, chemical modifications of sugarcane bagasse and sisal fibers using lignin (previously hydroxymethylated) were carried out under different reaction times (15, 30, and 60 min). The composition (holocellulose, hemicelluloses, cellulose, and lignin contents) of the treated and untreated fibers was evaluated. Phenolic composites were prepared using unmodified and modified fibers via compression molding process under temperature. Izod impact, water absorption tests, and scanning electron microscopy were performed to evaluate composite properties. The resin and lignin were characterized by size exclusion chromatography. Results showed that there was a tendency of reducing water absorption for composites prepared from modified fibers. Impact strengths of composites reinforced with sugarcane bagasse with modified fibers were similar to the ones with unmodified fibers (around 20 J/m). However, impact strengths for composites reinforced with modified sisal fibers (around 104 J/m for 15 min of reaction time) were higher than the ones with unmodified fibers (around 95 J/m). Therefore, the usage of lignin as a modifier agent of vegetal fiber surfaces to increase fiber–matrix adhesion for phenolic composites is a strategic alternative for improving products through simple, eco-friendly, and low-cost procedures.

The aim of this work is to model the water absorption mechanism of the polypropylene/date palm fibers composite materials after their exposure at different immersion conditions. For short immersion period, a model combining the Fick’s law and the time temperature stress principle has been proposed to describe the water absorption mechanism. However, it has been noted that, after a saturation time, the water diffusion mechanism leads to a physical degradation and a mass loss into the composite material, especially under high temperatures and long times of water immersion. Microscopic observations have revealed a decrease of the interfacial adhesion between the fibers and the matrix and fiber degradations. A general new model describing the evolution of the water uptake mechanism and the degradation phenomenon has been also proposed in the present work. A good agreement between the theoretical and experimental data has been obtained.

In this work, we have investigated the impact of micro-silica (SiO2), micro-alumina-tri-hydrate (ATH), and mixture of micro/nano-sized particles (ATH + SiO2) on electrical, tracking and erosion, and water absorption characteristics of silicone rubber (SiR)-based novel composites. SiR-blends with varying concentrations by weight percent (wt%) of ATH and SiO2 were prepared by simple blending in a two-roll mixing mill. Tracking/erosion and water absorption resistance properties of SiR-blends were analyzed using the inclined plane test and water immersion tests, respectively, according to ASTM standards. Dielectric strength, volume and surface resistivity, tracking/erosion resistance, and water penetration resistance properties of SiR composites were determined and discussed. SiR composites with ATH showed enhanced dielectric strength, volume and surface resistivity, erosion resistance, and initial tracking voltage compared to SiO2-filled composites. Further, the ATH and SiO2 co-filled specimens showed better water immersion resistance compared to samples only filled with ATH or SiO2. We presume characterization results presented in this work will help researchers to optimize the performance of SiR for outdoor high-voltage insulation applications.

The temperature sensitivity of underlying water absorption bands can lead to baseline artifacts or apparent spectral band shifts in near infrared spectra and can negatively impact multivariate calibration models used in quantitative analyses. To address this issue, efforts can be made to suppress the temperature-induced spectral variation or knowledge of the temperature can be used to adjust the calibration. To facilitate the latter approach, we explored the ability to estimate the aqueous temperature of the sample directly from the combination region of the near infrared spectrum. This temperature modeling strategy addresses applications in which it is difficult to obtain an accurate sample temperature with a conventional measurement probe. Temperature models were developed by use of partial least-squares regression combined with the discrete wavelet transform. Models were constructed from the 5000 to 4000 cm−1 region of near infrared spectra for pH 7.4 buffer solutions over the temperature range of 20.0–40.5℃. The long-term predictive ability of the models was assessed by use of 13 sets of prediction spectra collected over the course of 13 months, yielding values of the root mean square error of prediction ranging from 0.19 to 0.36℃. In addition, laboratory-prepared solutions of glucose, mixture solutions of glucose, lactate, urea in buffer, and bovine plasma were used to assess the predictive ability of the temperature models in increasingly complex matrixes. The effects of pH and buffer molarity were also studied. While increasing the complexity of the spectral background resulted in increases in root mean square error of prediction (0.33–1.01℃), retuning the models to incorporate the modified spectral backgrounds lowered the resulting root mean square error of prediction values to the range of 0.3℃. This work demonstrates the practical utility of spectral-based temperature measurements that employ the absorbance of the water baseline rather than the peak absorbance.

In this study, the fatigue behavior of recycled polypropylene reinforced with short glass fiber with different weight fractions (5 wt%, 10 wt%, 20 wt%, and 30 wt%) was compared to pure polypropylene under dry and wet conditions. The specimens were manufactured using injection molding process. The results show that addition of short glass fiber to recycled polypropylene resulted in increasing water uptake compared to pure polypropylene. However, flexural fatigue strength of recycled polypropylene reinforced with short glass fiber with 10 wt%, 20 wt%, and 30 wt% exhibits higher relative fatigue strength than pure polypropylene under dry and wet conditions. Fatigue strength increases with the increase in fiber contents increased in recycled polypropylene matrix.