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Glass fiber/polymer composites are widely utilized in many structural applications because of their high specific strength and stiffness-to-weight ratios. In this study, woven glass fiber/epoxy was hybridized with short glass fibers of different lengths (2, 4, 6, 2+4, 2+6, and 4+6 mm) and contents (3, 6, 9, and 12 wt%) to produce hybrid woven SGF/epoxy composites. Variations in the thickness, fiber volume fraction, density, and void content of the prepared composites were determined. Mechanical tests such as tensile and Charpy impact tests were conducted. Compared to the woven fabric composites without short glass fibers (control samples), the tensile strength increased by approximately 13% at an optimum weight fraction of 3 wt% using short glass fiber lengths of 4 mm. Meanwhile, the incorporation of short glass fibers into the woven glass composites decreased the tensile modulus for all lengths. The maximum enhancement in the impact strength (approximately 14%) was achieved by the hybrid composite samples reinforced with 4 mm of short glass fibers at 3 wt%. This hybrid composite offers 18% and 20% improvements in the specific tensile and impact strengths, respectively. In summary, filling the woven fabric composites with specified short fiber contents and lengths can increase their mechanical performance when resin-rich regions are reinforced with short fibers without forming relatively thick interleaves between the woven fabric plies

Abstract Background In dentistry, glass-ionomer cements (GICs) are extensively used for a range of applications. The unique properties of GIC include fluoride ion release and recharge, chemical bonding to the tooth’s hard tissues, biocompatibility, a thermal expansion coefficient like that of enamel and dentin, and acceptable aesthetics. Their high solubility and poor mechanical qualities are among their limitations. E-glass fibers are generally utilized to reinforce the polymer matrix and are identified by their higher silica content. Objectives The purpose of the study was to assess the impact of adding (10 wt% and 20 wt%) silane-treated E-glass fibers to traditional GIC on its mechanical properties (compressive strength, flexural strength, and surface hardness) and solubility. Methods The characterization of the E-glass fiber fillers was achieved by XRF, SEM, and PSD. The specimens were prepared by adding the E-glass fiber fillers to the traditional GIC at 10% and 20% by weight, forming two innovative groups, and compared with the unmodified GIC (control group). The physical properties (film thickness and initial setting time) were examined to confirm operability after mixing. The evaluation of the reinforced GIC was performed by assessing the compressive strength, flexural strength, hardness, and solubility (n = 10 specimens per test). A one-way ANOVA and Tukey tests were performed for statistical analysis (p ≤ 0.05). Results The traditional GIC showed the least compressive strength, flexural strength, hardness, and highest solubility. While the GIC reinforced with 20 wt% E-glass fibers showed the highest compressive strength, flexural strength, hardness, and least solubility. Meanwhile, GIC reinforced with 10 wt% showed intermediate results (P ≤ 0.05). Conclusion Using 20 wt% E-glass fiber as a filler with the traditional GIC provides a strengthening effect and reduced solubility.

Highlights Environmental hazards caused by the ever‐increasing end‐of‐life (EoL) glass fiber reinforced polymer (GFRPs) composite waste is of major concern for the sustainable development of the industry. Compared to land filling or incineration, pyrolysis is one of the most promising environmentally friendly methods of disposal of EoL GFRPs. Pyrolysis not only results in recovery of clean glass fibers but other valuable products, such as oils. However, long processing time at elevated temperature leads to aggravation of already existed surface flaws along with the structural changes. Therefore, thermal conditioning of glass fibers results in severe deterioration of the strength in recovered fibers and hence limiting the use of recovered fibers to low end‐products. In this study, a new strategy was adopted where instead of complete cleaning of the fibers at pyrolysis stage, the fibers were partially oxidized and the complete removal of char from the surface of glass was done during hot alkaline etching. This strategy was opted to enhance the quality of the required fibers while reducing the processing time. The results showed ~200% increase in strength of fibers after the combined treatment of pyrolysis and post etching compared to the just pyrolyzed samples with etching time of just 1 min. End‐of‐life panels of GFRPs were pyrolyzed under inert environment of Argon. Residual char was partially removed through post oxidation under flowing air. Hot alkaline etching resulted in complete removal of char and surface defects. Partial oxidation and short etching cycles resulted in improved strength of recovered glass fibers. [ABSTRACT FROM AUTHOR]

This study experimentally investigates the influence of metal chips and glass fibers on the mode I fracture toughness, energy absorption, and tensile strength of polymer concretes (PCs) manufactured by waste aggregates. A substantial portion of the materials employed in manufacturing and enhancing the tested polymer concrete are sourced from waste material. To achieve this, semi-circular bend (SCB) samples were fabricated, both with and without a central crack, to analyze the strength and fracture behavior of the composite specimens. The specimens incorporated varying weight percentages comprising 50 wt% coarse mineral aggregate, 25 wt% fine mineral aggregate, and 25 wt% epoxy resin. Metal chips and glass fibers were introduced at 2, 4, and 8 wt% of the PC material to enhance its mechanical response. Subsequently, the specimens underwent 3-point bending tests to obtain tensile strength, mode I fracture toughness, and energy absorption up to failure. The findings revealed that adding 4% brass chips along with 4% glass fibers significantly enhanced energy absorption (by a factor of 3.8). However, using 4% glass fibers alone improved it even more (by a factor of 10.5). According to the results, glass fibers have a greater impact than brass chips. Introducing 8% glass fibers enhanced the fracture energy by 92%. However, in unfilled samples, aggregate fracture and separation hindered crack propagation, and filled samples presented added barriers, resulting in multiple-site cracking. [ABSTRACT FROM AUTHOR]

The observation of fibers in salvadora persica roots inspired us to consider the idea of using them as reinforcement to create an innovative composite. The current work focuses on the volumetric mass density, extraction, molding, and mechanical testing of composites and hybrid composites made from salvadora persica roots and glass fibers reinforced with two types of polyester matrix, chosen due their characteristics suitable for use in different orientations. Various extraction and combination methods have been used to identify an optimal approach for obtaining fibers from salvadora persica roots, considering its chemical composition (hemicellulose, pectin, and lignin). In this investigation, the hand lay-up method was used to mold specimens with different geometries. The composite and hybrid composite were combined with a polyester matrix and subjected to various mechanical tests namely; tensile, impact resistance, and water absorption. The results indicate that reinforcing polyester resins with SP fibers, whether long or short, enhances the overall mechanical properties of the composite. Additionally, improved adhesion between salvadora persica roots fibers and resin was observed.

Bismuth (Bi)‐doped glass fibers are being developed into next‐generation broadband amplifiers and tunable lasers. Yet, the well‐developed Bi‐doped fiber devices only realize silica‐based optical fibers prepared by the modified chemical vapor deposition method, which faces challenges such as low doping concentration, high cost, intricate device structure, and high preparation difficulty. Here, a novel highly Bi‐doped multicomponent phosphate glass was developed. The high ion solubility of this phosphate glass facilitates achieving a Bi doping concentration of 8 mol%. The introduction of aluminum nitride (a new reducing agent) can create a local reducing environment, further increasing the concentration of low‐valence near‐infrared (NIR) active Bi ions. Furthermore, the resulting enhanced highly Bi‐doped multicomponent phosphate glass with efficient 900–1600 nm NIR emission can be drawn into corresponding optical fibers by a rod‐in‐tube method. Broadband NIR amplified spontaneous emission with a 3 dB bandwidth of 275 nm was achieved in this new fiber. As far as we know, this is the first successful preparation of Bi‐doped multicomponent phosphate glass fiber. Our results indicate that this fiber will be a powerful alternative to Bi‐doped silica‐based fibers for the preparation of related Bi‐doped fiber devices. [ABSTRACT FROM AUTHOR]

Interlayer hybrid foldcore sandwich structures have been introduced in this study. Both facesheets and foldcores were hybridized in the same ply sequence with two layers of plain woven carbon (C) and two layers of satin woven glass (G) fiber prepregs (Carbon-to-Glass ratio 1:1). Foldcore sandwich structures with six-ply combinations were designed including two symmetric layups (GCCG and CGGC) and four asymmetric layups (CGCG, GCGC, CCGG, and GGCC). The static compression and low-velocity impact performance of foldcore sandwich structures of different ply sequences were investigated. A user-defined material subroutine (VUMAT) was employed to characterize the damage evolution of composite materials based on selected failure criteria. The findings revealed that hybridization was effective in enhancing its energy absorption value of pure carbon fiber foldcore sandwich structures in terms of static compression performance. The damage degree of the interlayer hybrid foldcore sandwich structures increased gradually with the increasing impact energy. Moreover, the damage of facesheet was mainly caused by fiber tensile, matrix tensile damage and delamination, and damage of foldcore was mainly delamination. GCGC sandwich panel with asymmetrical cross-ply sequence has the optimal load bearing capacity, and CGGC sandwich panel with symmetrical layup has a strong energy absorption capacity under high-energy impact load. The foldcore sandwich structure showed smaller peak load, longer crushing distance, and more energy absorption value under larger oblique impact angle. The simulation and experimental results show good agreement in peak force, maximum energy absorption, and damage mode. [ABSTRACT FROM AUTHOR]

The 3D printing of continuous-fiber composites is currently relevant to engineers and researchers. This study aims to characterize and predict the mechanical properties of Onyx/glass fiber specimens printed using 3D printing. The work assesses the impact of glass fiber printing parameters on the mechanical behavior of printed parts and proposes analytical and numerical methods to predict mechanical properties. A physicochemical analysis was conducted on 3D printed continuous glass fibers. The study also investigated the impact of fiber printing parameters on composite parts. The results indicate that the 3D-printed glass fibers consist of nylon, continuous glass fibers, and voids (porosity), which range from 58% to 63%, 31% to 38%, and 5% to 8%, respectively. Mechanical characterizations indicate that printing fiber layers in blocks results in superior mechanical properties compared to printing alternating layers of glass fibers and Onyx. Additionally, the concentric mode of fiber printing can be challenging if the 'start rotation' parameter is not adjusted correctly. Premature specimen breakage occurred when fiber printing began within their useful length, resulting in a deformation at break that was approximately 34% less, depending on the starting position. The proposed analytical and numerical prediction methods had prediction errors of approximately 7% to 12% and 5% to 7%, respectively. Engineers can use these prediction approaches during the dimensioning phase of 3D printed composite parts. [ABSTRACT FROM AUTHOR]

Objective: To evaluate fracture resistance and failure type of coronally rehabilitated primary incisors with EverX Flow or Grandio Core post and core with or without fiber post. Materials and Methods: Forty-eight extracted maxillary primary incisors were root canal treated and obturated with Metapex. The coronal 4-mm of Metapex was removed to create 3-mm intracanal post space. Next, coronal enamel and radicular dentin surfaces were acid-etched, and a bonding agent was applied and light-cured. Based on intracanal post and 2-mm height core buildup materials, specimens were divided equally (n = 12) into 4 groups as follow; Group I (EverX Flow), Group II (Grandio Core), Group III (Fiber post, and EverX Flow), and Group IV(Fiber post and Grandio Core). The coronal restorations were finalized to 4-mm height using G-aenial Anterior composite and specimens were tested for fracture resistance. Force required to induce fracture was recorded and failure type was examined. Results: Fracture resistance of Fiber post and EverX Flow group was statistically significant high than other tested groups. However, fracture resistance of EverX Flow group showed non-statistically significant difference from that of Fiber post and Grandio Core group. Regarding failure type, no specimen presented root fracture, and all failures were favorable and repairable. Conclusion: EverX flow post and core with or without fiber post enhanced fracture resistance of restored primary incisors compared to Grandio Core alone. Clinical relevance: EverX flow post and core system with or without fiber post could be a promising restorative option for severely destructed primary incisors.

The work analyzes the fracture topography of composite specimens subjected to three-point bending - static and impact. Scanning electron microscopy was used for this purpose. The tests were performed for two different materials - polypropylene and polyamide PA6, each reinforced with unidirectional glass fibers. In one case, the fibers were distributed evenly, and in the other, there were areas more and less reinforced with fibers. It was observed that in all cases the tension and compression parts could be clearly distinguished. However, for different materials and with different methods of destruction, different failure mechanisms were observed, noted based on the analysis of the fracture topography. It was observed that regardless of the loading method and material, in the tensile part there were visibly protruding fibers, and in the compressed part it was the matrix, not the fibers, that was destroyed. In the case of statically loaded samples, damage occurred at the macrostructural level, and in the case of dynamically loaded samples, at the microstructural level. Additionally, samples with uneven fiber distribution were more susceptible to delamination.

In this research, the effect of adding aluminum oxide nanoparticles on the flexural strength of glass/phenolic composites that were exposed to water environment was experimentally investigated. To make glass/phenolic composites, IL‐800 phenolic resin, H002 hardener, T400 bidirectional glass fibers and Al2O3 nanoparticles were used. Four‐layer composite plates were made by hand layup method. Beam‐shaped samples were extracted from the plates with the help of laser cutting method. Rectangular composite beams made of glass/phenolic and Al2O3/glass/phenolic were subjected to three‐point flexural test. The moisture absorption test was continued until the amount of water absorption reached a constant level. Bending test was performed on the samples before and after immersion in water. Based on the results, the average flexural strength of the samples after water absorption shows a decrease of about 15%. This parameter is equal to 118.96 MPa for glass/phenolic composite samples immersed in water, and by adding 0.25 wt% of Al2O3 nanoparticles into the matrix material of glass/phenolic composite samples, the flexural strength reaches 142.54 MPa, which shows an increase of 19.82% compared to samples without nanoparticles. Furthermore, the amount of flexural modulus decreases after water absorption, and the addition of nanoparticles in the base material can compensate this reduction. Scanning electron microscopy images illustrate that the addition of Al2O3 nanoparticles into the phenolic resin can enhance the strength of matrix material and improve the adhesion of glass fibers to the resin. Highlights: Addition of nano Al2O3 reduces water absorption of glass/phenolic composites.Nano Al2O3 improves composite flexural strength after water absorption.Addition of nano Al2O3 increases the adhesion between the layers of the specimens. [ABSTRACT FROM AUTHOR]

Elium® Acrylic/Glass Fiber thermoplastic laminate composites are liable to develop irreversible local defects under quasi‐static loading. To reinforce the damaged material, repair is a cost‐effective mechanical alternative. The present study investigates the tensile behavior of an Elium® glass‐fiber‐based acrylic laminate composite panel, repaired by vacuum bonding with Elium® repair resin and double overlap of external patches (DP). The results obtained for all repaired laminate composites E190/GF_D(10, 20, 30)R with diameters 10, 20, and 30 mm showed an improvement in the mechanical properties of the repaired panels, compared with the drilled and pristine samples. Average load recovery rates were significant for E190/GF_D10R (7.9%, 3.55%, 13%) E190/GF_D20R (23%, 18%, 3.32%), E190/GF_D30R (7.2%, 9.36%, 32.37%) at strain rates of 0.001, 0.01, and 0.05 s−1 respectively. Finite element (FE) models for the virgin, drilled, and repaired composite, performed by coupling the Hashin criteria with the cohesive zone model (CZM), provided a relevant prediction of intra‐ and interlaminar failures of these woven laminated composites. Highlights: The effect of vacuum bonding repair with Elium E351 EOT resin was studied.Symmetrical repair of acrylic laminate drilled by fiberglass patches.Tensile strength of the repaired laminates was investigated.Intra‐ and interlaminar damage was predicted by finite elements modeling. [ABSTRACT FROM AUTHOR]

A cost-effective solution to the problems that the automotive industry is facing nowadays regarding regulations on emissions and fuel efficiency is to achieve weight reduction of automobile parts. Glass fiber-reinforced polymers are regularly used to manufacture various components, and some parts may also contain thermoplastic elastomers for toughness improvement. This work aimed to investigate the effect of styrene-(ethylene-co-butylene)-styrene triblock copolymer (E) and treated fly ash (C) on the morphological, thermal, and mechanical properties of long glass fiber (G)-reinforced polypropylene (PP). Results showed that the composites obtained through melt processing methods presented similar thermal stability and improved (nano)mechanical properties compared to 25–30 wt.% G-reinforced PP composites (PP-25G/PP-30G). Specifically, the impact strength and surface hardness were greatly improved. The addition of 20 wt.% E led to a 25–39% increase in impact strength and surface elasticity, while the addition of 6.5 wt.% C led to a 16% increase in surface hardness. The composite based on 25 wt.% G, 6.5 wt.% C, and 20 wt.% E presented the best-balanced properties (8–17% increase in impact strength, 38–41% increase in axial strain, and 35% increase in surface hardness) compared with PP-30G/PP-25G. Structural and morphological analysis confirmed the presence of a strong interaction between the components that make the composites. Based on these results, the PP–G–E–C composites could be presented as a viable material for automotive applications. [ABSTRACT FROM AUTHOR]

Advanced oxidation processes (AOPs) are eco-friendly, and promising technology for treating dye containing wastewater. This study focuses on investigating the removal of methyl orange (MO), an azo dye, from a synthetic wastewater through the use of hydrodynamic cavitation (HC), both independently and in combination with hydrogen peroxide (H2O2), as an external oxidant, as well as photocatalysis (PC) employing catalyst coated on glass fibers tissue (GFT). The examination of various operating parameters, including the pressure drop and the concentration of H2O2, was systematically conducted to optimize the degradation of MO. A per-pass degradation model was used to interpret and describe the experimental data. The data revealed that exclusive employment of HC using a vortex-based cavitation device at 1.5 bar pressure drop, resulted in a degradation exceeding 96 % after 100 passes, equivalent to 230 min of treatment (cavitation yield of 3.6 mg/kJ for HC), with a COD mineralization surpassing 12 %. The presence of a small amount of H2O2 (0.01 %) significantly reduced the degradation time from 230 min to 36 min (16 passes), achieving a degradation of 99.8 % (cavitation yield of 6.77 mg/kJ for HC) with COD mineralization rate twice as much as HC alone, indicating a synergistic effect of 4.8. The degradation time was further reduced to 21 min by combining HC with PC using TiO2-coated glass fibers and H2O2, (cavitation yield of 11.83 mg/kJ for HC), resulting in an impressive synergistic effect of 9.2 and COD mineralization twice as high as the HC/H2O2 system. The results demonstrate that HC based hybrid AOPs can be very effective for treating and mineralizing azo dyes in water.

Expanded polystyrene (EPS) polymers are widely used in insulation and packaging applications. If their waste hasn't been managed well and due to their long degradation time, they will cause severe environmental problems for human beings, plants, and animals. Therefore, recycling could be one of the acceptable solutions to overcome such problems in addition to reinforcing them to recover the decay in properties resulting from recycling. In this work two types of EPS have been recycled at different temperatures from 140 to 260°C, and then reinforced by E-glass fibers in mat form and as random short fibers with varied composition from 5 to 25 wt%. The samples have been prepared by homemade thermal press and the tensile properties such as strength, modulus, and ductility have been investigated showing an obvious enhancement of these properties upon an increase in temperature to certain level and with fiber content and length exceeding their critical lengths. Furthermore, interfacial adhesion has been studied by estimating the strength and modulus efficiency factors. The results show that the E-glass fibers could improve the strength with more than 300%. [ABSTRACT FROM AUTHOR]

Abstract Background Zinc-oxide eugenol (ZOE) cements are among the most used temporary materials in dentistry. Although ZOE has advantages over other temporary fillers, its mechanical strength is weaker, so researchers are working to improve it. E-glass fibers have emerged as promising reinforcing fibers in recent years due to their strong mechanical behavior, adequate bonding, and acceptable aesthetics. Objectives To evaluate and compare the compressive strength, surface microhardness, and solubility of the ZOE and those reinforced with 10 wt.% E-glass fibers. Methods A total of 60 ZEO specimens were prepared; 30 specimens were reinforced with 10 wt.% E-glass fibers, considered modified ZOE. The characterization of the E-glass fibers was performed by XRF, SEM, and PSD. The compressive strength, surface microhardness, and solubility were evaluated. Independent sample t-tests were used to statistically assess the data and compare mean values (P ≤ 0.05). Results The results revealed that the modified ZOE showed a significantly higher mean value of compressive strength and surface microhardness while having a significantly lower mean value of solubility compared to unmodified ZOE (P ≤ 0.05). Conclusion The modified ZOE with 10 wt.% E-glass fibers had the opportunity to be used as permanent filling materials.

This study experimentally investigates the influence of metal chips and glass fibers on the mode I fracture toughness, energy absorption, and tensile strength of polymer concretes (PCs) manufactured by waste aggregates. A substantial portion of the materials employed in manufacturing and enhancing the tested polymer concrete are sourced from waste material. To achieve this, semi-circular bend (SCB) samples were fabricated, both with and without a central crack, to analyze the strength and fracture behavior of the composite specimens. The specimens incorporated varying weight percentages comprising 50 wt% coarse mineral aggregate, 25 wt% fine mineral aggregate, and 25 wt% epoxy resin. Metal chips and glass fibers were introduced at 2, 4, and 8 wt% of the PC material to enhance its mechanical response. Subsequently, the specimens underwent 3-point bending tests to obtain tensile strength, mode I fracture toughness, and energy absorption up to failure. The findings revealed that adding 4% brass chips along with 4% glass fibers significantly enhanced energy absorption (by a factor of 3.8). However, using 4% glass fibers alone improved it even more (by a factor of 10.5). According to the results, glass fibers have a greater impact than brass chips. Introducing 8% glass fibers enhanced the fracture energy by 92%. However, in unfilled samples, aggregate fracture and separation hindered crack propagation, and filled samples presented added barriers, resulting in multiple-site cracking.

This study investigates the effect of super absorbent polymers (SAPs) and glass fiber (GF) additions on the properties of lightweight concrete. The SAPs act as a pore-forming agent, with the addition of various GF contents (0.1–1.0% by weight of dry ingredients). The results indicate that the use of SAPs at 7% by weight of OPC produces a product with similar properties to conventional lightweight concretes which meet the ASTM C332–17 standard. The addition of GF to the mixture tends to reduce the dry density and compressive strength, but increases the porosity and flexural strength. The results indicate that the use of SAPs at 7% by weight of OPC produces a product with similar properties to conventional lightweight concretes which meet the ASTM C332–17 standard. The 28-day compressive strengths decreased from 7.04 ± 0.07 for control sample to 4.59 ± 0.11 MPa, while the flexural strengths increased from 3.89 ± 0.04 for control sample to 6.72 ± 0.06 MPa. High-porosity lightweight concrete prepared from SAPs and GF shows reduced thermal conductivity and an increased sorption rate. The initial rate of water absorption gradually increases from 2.48 × 10−1 mm/sec0.5 in the sample without GF up to 5.45 × 10−1 mm/sec0.5 in the sample containing 1.0 wt.% GF. Comparison with the literature indicates that the use of SAPs as pore-forming agents in conjunction with GF has the potential to produce fiber-reinforced lightweight concrete with improved properties.

Hemihydrate phosphogypsum (HPG), obtained as a cementitious material from the dewatering of phosphogypsum, can be widely used in the preparation of construction materials owing to its low cost and environmental friendliness. However, current reports on HPG mainly focus on hydration behavior, mechanical properties, and durability, and there are few studies focusing on the enhancement of HPG toughness. In this work, glass fibers (GF) and fly ash (FA), as composite reinforcement, were mixed with HPG during its preparation to obtain eco-friendly, high-toughness gypsum. The workability, mechanical, microstructural, financial and environmental properties of the HPG-based composites with different GF volume dosages (0, 0.5, 1.0, and 1.5 vol%) and FA weight percentages (0, 10, 20, and 30 wt%) were comparatively investigated. The results show that the addition of an appropriate amount of FA can improve the interface transition zone between GF and the matrix and effectively increase the flexural strength and toughness of the composites. For the optimal mixture containing 1.5 vol% GF and 20 wt% FA, the flexural strength and toughness were 50.7% and 82.2% higher, respectively, than those of the mixture without FA and 99.2% and 675.3% higher, respectively, than those of the control sample (without GF and FA). Cost-benefit and environmental impact analyses also indicated that this composite was the most economical and environmentally friendly. Thus, this work provides an effective approach to achieve the high-value utilization of two major industrial by-products.

This paper introduces a sustainable sewage rehabilitation solution, utilizing repurposed glass fibers for enhanced chemical resilience and environmental conservation. The approach involves dividing a unitary pipe into segments, assembled during commissioning, aiming to reduce installation and transportation costs, particularly in less accessible areas. Each pipe segment comprises a multi-layered glass fiber composite sandwich, joined by an adhesive reinforced with recycled glass fibers. The glass fiber-reinforced plastic (GFRP) pipe features a core of blended sand impregnated with resin, an outer layer for impact resistance, and an inner layer to prevent corrosion. Chemical resilience is assessed through a 10,000 h strain corrosion study exposing both unitary and two-piece circular GFRP pipes to sulfuric acid in a deflected condition. An apparent hoop tensile test evaluates mechanical integrity before and after exposure. The experimental results reveal that the two-piece pipe with a tongue and groove joint (TGJ) with recycled glass fiber adhesive exhibits superior long-term bending stress and failure strain % compared to unitary pipes. This enhancement is attributed to the TGJ’s improved load-bearing capability and chemical resistance. The failure strain % of the two-piece pipe (1.697%) is higher compared to the unitary pipe (1.2613%). The long-term bending stress of the two-piece pipe obtained is 119.94 MPa whereas the unitary pipe reaches 93.48 MPa at the 50-year mark. The cost analysis supports the adoption of the two-piece pipe over unitary pipes due to a 40% reduction in carbon emissions and transportation cost. The novelty lies in the utilization of multi-piece pipes with enhanced chemical resilience, achieved through the incorporation of milled fiberglass reinforcements in the TGJ. Strain corrosion tests take a long time to perform; hence, an accelerated test is needed to improve the current recommended testing standard.

The work analyzes the fracture topography of composite specimens subjected to three-point bending - static and impact. Scanning electron microscopy was used for this purpose. The tests were performed for two different materials, namely polypropylene and polyamide PA6, each reinforced with unidirectional glass fibers. In one case, the fibers were distributed evenly, and in the other, there were areas more and less reinforced with fibers. It was observed that in all cases the tension and compression parts could be clearly distinguished. However, for different materials and with different methods of destruction, varying failure mechanisms were observed, noted based on the analysis of the fracture topography. It was observed that regardless of the loading method and material, in the tensile part there were visibly protruding fibers, and in the compressed part it was the matrix, rather than the fibers, that was destroyed. In the case of statically loaded samples, damage occurred at the macrostructural level, and in the case of dynamically loaded samples, at the microstructural level. Additionally, the samples with uneven fiber distribution were more susceptible to delamination. [ABSTRACT FROM AUTHOR]

This research investigates the influence of kevlar and glass fiber reinforcements on the mechanical and thermal properties of epoxy/vinyl ester (hybrid resin) composite. The hybrid resin was synthesized by achieving an interpenetrating network between epoxy and vinyl ester. The composites were characterized using tensile, flexural, impact, and thermo‐gravimetric analysis (TGA). Scanning electron microscopy was employed to analyze surface morphology whereas Fourier‐Transformation Infrared Spectroscopy (FT‐IR) was used to investigate the possible interaction between the constituents of the composites. The findings have shown a notable improvement in the mechanical properties after the hybridization of the resin. For reference, the tensile strength of glass/hybrid resin and kevlar/hybrid resin composites were observed to increase by 8.33% and 23.65%, as compared to glass/epoxy and kevlar epoxy composites respectively, whereas, the bending strength of these composites was improved by 8.36% and 30.61%, respectively. TGA also showed an enhanced thermal stability of the hybrid resin‐based composites. Such improvements are noticed due to multi‐resin incorporation (the oxirane group of epoxy reacts with the hydroxyl group of vinyl ester), confirmed by the FTIR, TGA, and morphological analysis. This study signifies that the proposed hybrid composites are better in terms of strength and modulus relative to conventional metallic materials. Highlights: The paper presents the development of novel hybrid resin, reinforced with synthetic fibers.Hybrid resin is imparted positively and is highly favorable in improving the mechanical properties of composites.The tensile strength of novel composites is increased by 8.33% and 23.65% relative to their base specimens, and a similar trend is observed in flexural and impact analysis.Fractured analysis showed that composite laminates deteriorated more intensely due to cohesive matrix fracture; adhesion failure was not observed at all, as evidenced by the emergence of micro‐cracks in resin.Developed novel composites exhibited maximum thermal stability; residual char in glass/epoxy/vinyl‐ester composite attained 17.81% higher, whereas kevlar/epoxy/vinyl‐ester achieved 3.56% relative to glass/epoxy and kevlar/epoxy base samples. [ABSTRACT FROM AUTHOR]