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This study fabricates multiscale glass fiber/epoxy composites by incorporating graphene nanoparticles (GNPs) and zinc oxide nanoparticles (ZnO NPs) to investigate the influences of NPs on the mechanical properties of composites. The composites are manufactured using the compression molding technique with different GNP contents (i.e., 0, 0.5, 1, and 1.5 wt.%), whereas the contents of glass fibers and ZnO NPs remained the same at 40 and 4 wt.%, respectively. Their mechanical properties, chemical compositions, and fracture morphologies are then evaluated. It is found that the mechanical properties of composites improve significantly at a lower content (i.e., 0.5 wt.%) of GNPs and tend to decrease at higher contents (i.e., 1 and 1.5 wt.%). The composite is composed of 0.5 wt.% GNPs exhibit maximum tensile modulus and strength of 6.74 GPa and 230.25 MPa, and flexural modulus and strength of 16.43 GPa and 831.79 MPa, respectively, impact strength of 47.25 kJ m−2, and maximum hardness (97.96 Shore D), among all nanocomposites. Moreover, fracture morphologies reveal that composite failure is predominately caused by fiber breakage, fiber‐matrix debonding, voids, and GNP agglomeration. The outcomes of this study provide some insights to promote the application of manufactured multiscale composites in the aerospace, automotive, and marine industries. [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]

Composites with excellent flame retardant and mechanical properties are in high demand in the aerospace and various industrial fields. Glass fiber (GF) reinforced polyimide (PI) composites (GFRPCs) were fabricated using a simple ball milling and hot pressing technique. The effect of GF content on the thermal stability, mechanical and flame retardant properties of composites has been systematically studied. The Rockwell hardness of GFRPCs increase with increasing GF content, while the compressive strength, impact strength and flexural strength initially show an increase followed by a decrease due to the excellent dispersibility of the fillers and the strong interfacial interaction between the one‐dimensional GF and PI matrix. Thermogravimetric analysis results show that the addition of GF with very low thermal conductivity and excellent temperature resistance can effectively improve the thermal stability of PI. Adding GF into PI can obviously improve the limiting oxygen index value. Moreover, as the GF content increased, the time to ignition of the composites prolonged while total heat release decreased. These findings suggest a viable solution for enhancing both the flame retardance and mechanical properties of PI‐based composites. Highlights: GFRPCs with high GF content fabricated via ball milling‐hot pressing method.Silane modified GF obviously improves the thermal stability of PI matrix.GFRPCs‐28 exhibits superior mechanical properties.An increases in time to ignition (TTI) and mass residual rate (MRR) of the GFRPCs was observed on adding GF. [ABSTRACT FROM AUTHOR]

The natural and synthetic fibers are combined in a single composite to achieve a balance between the desired strength and cost considerations. In this study, the vacuum resin transfer moulding process was used to prepare an epoxy‐based composite. The composite consisted of grewia optiva as the natural fiber and glass fiber as the synthetic fiber, both with a fixed weightage of 10 %. Dolomite was used as a filler with varying content (0 %, 5 %, 10 %, and 15 weight %). The physical, mechanical, erosion wear and morphological behavior of the epoxy‐based composite were investigated. The inclusion of dolomite filler significantly increased the composite hardness and impact strength but reduced its tensile and flexural strength. At a dolomite filler content of 10 weight %, the erosive wear was reduced, while it increased at higher dolomite filler contents. The composite was examined using the L16 array, and the minimum wear rate was observed at an impingement angle of 30°, a velocity of 10 m/s, and an erodent size of 150 μm. Morphological studies were conducted to explore the possible mechanism for the variation in erosive wear at different dolomite contents in the hybrid composites. [ABSTRACT FROM AUTHOR]

Polyamide (PA) is the mostwidely used type of semi‐crystalline polymer among engineering plastics, with its low density and high mechanical properties. But the high moisture absorption of PA6 limits its use in some areas. Blending and the addition of reinforcement can decrease the moisture absorption value of PA6. In this research, the PA6/PA610 blends and glass fiber (GF) reinforced PA6/PA610 composites were fabricated, and the features of these blends‐composites were examined. The blends and composites were produced by using extrusion and injection molding methods and characterized by water absorption (WA) test, tensile test, scanning electron microscopy (SEM), dynamic mechanical analysis (DMA), thermogravimetric analysis, and differential scanning calorimetry (DSC). The loading rates of GF were used as 10–20‐ 30–40 wt%. According to the tensile test consequences, the highest increase in the tensile strength for the composites was observed at 30% GF ratio. DMA results demonstrated an increase in loss modulus and storage with the increasing fiber amount. It is observed that the WA value of neat PA6 was diminished by blending with PA610 and adding an increasing amount of GF. [ABSTRACT FROM AUTHOR]

Due to environmental issues and high cost of synthetic fibers, natural or cellulosic fibers have emerged as a promising reinforcement for polymer composites. The hybridization of natural fiber with synthetic fiber is a useful technique to improve the mechanical properties instead of using the natural fibers alone. This research aims to evaluate the influence of glass fiber hybridization on the mechanical properties of continuous, unidirectional, alkali (NaOH)‐treated kenaf‐epoxy composites. At first, the effect of treatment of various concentrations (3, 5, 7, and 9% w/v) of NaOH on the structure of single kenaf fiber was characterized using XRD, SEM, FTIR, and tensile testing. At the optimum 5% alkali concentration the tensile strength, modulus, and %elongation of the kenaf fibers were enhanced by 81%, 114%, and 42%, respectively. The effect of hybridization of 5% NaOH treated kenaf along with glass fiber on the improvement in tensile, flexural, and impact properties for hand laid kenaf‐glass‐epoxy hybrid composite laminates was established. The overall matrix to fiber weight ratio of five different layup sequence laminates was maintained constant at 70:30. It can be concluded from the obtained results that the 15% glass and 15% kenaf fiber hybridized composites exhibited the maximum increment in tensile strength and modulus (68.5% and 19.5%, respectively) in comparison to the unhybridized composites. Further, the flexural strength and modulus were also improved by 21% and 67%, respectively, and the impact strength by 153%. The SEM fractography proved that alkali treatment of fibers improved the fiber‐matrix interfacial bonding whereas fiber breakage, fiber pull‐out and debonding were established as the main fracture mechanisms of hybrid composites. The findings of the present investigation on kenaf‐glass hybrid composites corroborate that they are suitable for secondary structural applications in construction and automobile sectors. [ABSTRACT FROM AUTHOR]

Steel fiber is the most common metal fiber used due to its cost‐effectiveness, high performance, and availability despite its heavyweight. This study is an attempt to evaluate the mechanical properties of steel/glass fiber and steel/basalt fiber‐reinforced epoxy composites. The symmetric hybrid laminates were produced by replacing the innermost 1, 2, 3, and 4 layers of steel fiber (200 mesh size) with basalt and glass fiber layers. The specimens were subjected to tensile, flexural, and Charpy impact tests in accordance with relevant ASTM standards. Moreover, fracture surfaces were analyzed, and the micrographs were obtained using a scanning electron microscope. The results showed that a high improvement in tensile strength was achieved with BS1–E (1 layer steel mesh–8 layers basalt) and GS1–E (1 layer steel mesh–8 layers glass) hybrid composites, with an increase of 528% and 233%, respectively, compared to steel fiber reinforced epoxy composites. Similarly, BS1–E and GS1–E hybrid composites showed the highest flexural strength increase of 82.2% and 66.8%, respectively, compared to steel fiber reinforced epoxy composites. Consequently, the potential to hybridize steel fiber with glass fiber and basalt fiber could create new materials with unique physical structures and synergistic effects on mechanical properties. [ABSTRACT FROM AUTHOR]

The amount of composite waste from decommissioned wind turbine blades grows rapidly and recycling solutions should be generated to overcome this environmental challenge. This research aims to further develop a recycling method to recover components of dismantled turbine blades by reusing them as reinforcement for new composites. Recycled short glass fibers from shredded blade composites are incorporated into polylactic acid (PLA) to fabricate a composite (15 wt% fiber) that could be used for 3D filament fabrication. To improve the mechanical properties of the composite, a coupling agent was employed to refine the interactions between PLA and recycled glass fibers at the interface of the two components and enhance the adhesion. Due to the inherent brittleness of PLA, which is aggravated with the addition of recycled glass fibers, a toughening agent involving chain‐end modification was incorporated into the composite to improve the toughness of the system. The concurrent outcome of the coupling agent and the toughener on the morphology, mechanical properties and thermal behavior of the composite was evaluated. The incorporation of 1,2,3,4‐butane tetracarboxylic acid and silane‐treating of the recycled fibers improved the strength by 30% and elongation at break and impact strength of the composite 3 and 2 times, respectively. [ABSTRACT FROM AUTHOR]

Using star‐branched polyamide 6 (SPA6) with hexafunctional cyclotriphosphazene core as a matrix resin and glass fiber (GF) as a reinforcing material, star‐branched polyamide 6/glass fiber (SPA6/GF) composites with different GF content were prepared by melt‐compounding method. The star‐branched structure of SPA6 and GF content have great effects on the properties of SPA6/GF composites. Compared with linear polyamide 6 (LPA6), SPA6 with star‐branched structure has low viscosity, high melt flowability and good impregnation and adhesion to GF, which endow SPA6/GF composites outstanding processability, good surface qualities and excellent mechanical properties even when the content of GF reaches 60 wt%. The use of SPA6 resin with star‐branched structure fundamentally solves the industry problem of traditional LPA6 resin in high‐filled modification. Such high‐performance SPA6/GF composites will provide great promise for large‐scale applications. [ABSTRACT FROM AUTHOR]

In the selection of materials for deep‐sea equipment, light weight and high strength are the most important criteria or requirements. In this paper, hollow glass microspheres (HGMS), expanded polystyrene (EPS), epoxy resin (EP) and curing agent were mixed to prepare hollow glass microspheres reinforced epoxy foam balls (HGMS‐EHS) by the rolling ball method. Glass fiber (GF) reinforced epoxy syntactic foam (GF‐ESF) was prepared by mixing HGMS‐EHS, HGMS, EP, GF, and curing agent using compression moulding method. By analyzing the mechanical properties and microscopic morphology of GF‐ESF, the results show that the addition of GF does enhance the compressive strength of epoxy syntactic foam. GF‐ESF has a density of 496 kg/m3, and its compressive strength is 30.48 MPa. By increasing the number of layers of HGMS‐EHS, the diameter of EPS, the density of HGMS and reducing the stacking volume of HGMS‐EHS, the density of ESF increased significantly thus subsequently increase the compressive strength. Therefore, the compressive strength and density should be considered comprehensively and find the best balance point in the process of preparing ESF. This paper could provide some suggestions for the preparation of deep‐sea epoxy composites. [ABSTRACT FROM AUTHOR]

Hybrid composites have become the focal point of research communities due to the balance in mechanical and ecological properties of such materials. Hybridization is an efficient technique to strengthen and enhance the performance of composite materials. In this research study, hybrid composites were prepared by embedding pineapple leaf and glass fibers in polypropylene polymers via the hot press molding compression technique. Mechanical tests were carried out to determine the tensile, flexural and Charpy impact properties of pineapple leaf/glass fiber‐reinforced hybrid composite laminates. Additionally, water absorption test was also conducted to investigate the influence of hybridization on the moisture uptake of hybrid composites. In accordance with the findings obtained, the hybridization of pineapple leaf with glass fibers was found to improve the mechanical properties and moisture uptake sensitivity of the composite laminates. The [G/P/G] composite laminates are especially promising, having comparable mechanical strengths to those of non‐hybrid [G/G/G] composite laminates. Meanwhile, the water absorption and diffusion coefficient of [G/P/G] composite laminates were 66.64% and 40.71% lower than non‐hybrid [P/P/P] composite laminates. Based on the findings obtained, it is anticipated that the hybridization of pineapple leaf and glass fibers endows the composite laminates with lightweight characteristic, remarkable mechanical properties and low moisture uptake sensitivity while improving the environmental friendliness of the materials. Therefore, hybrid composites have indeed attested a very high potential to be used in transportation sectors. [ABSTRACT FROM AUTHOR]

Hexaphenoxycyclotriphosphazene (HPCTP), modified with phenoxy groups based on hexachlorocyclotriphosphazene (HCCP), has been proved that have excellent thermal stability. In this article, HPCTP and glass fiber (GF) were added into the rigid polyurethane foam (RPUF) to improve the flame‐retardant and mechanical properties of RPUF. The mechanical properties of composite were measured by compressive strength test. The micrographs were observed by scanning electron microscopy. Furthermore, the flame‐retardant and thermal properties were investigated by limiting oxygen index, cone calorimeter test, and thermogravimetric analysis. The results showed that the addition of HPCTP and GF would improve the mechanical and flame‐retardant properties of RPUF. [ABSTRACT FROM AUTHOR]

Isotactic polypropylene (iPP) composite with two-scale reinforcement structure, i.e. nanoscale shish-kebab structure and micron-scale glass fiber (GF) with orientation, was fabricated by an oscillatory shear injection molding (OSIM) technology. The oscillatory shear flow provided by the OSIM gave rise to a high fraction of shish-kebab structures in the iPP composite, characterized by X-ray scattering technique. On the other hand, the oscillatory shear flow oriented GFs in the iPP composite, which was revealed by scanning electron microscopy measurement. The iPP composite with this two-scale reinforcement structure exhibited simultaneously remarkably enhanced tensile strength and impact strength. Fracture mechanism of this iPP composite was also proposed. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

doi: 10.1111/j.1741-2358.2010.00410.x Evaluation of the flexural strength and elastic modulus of resins used for temporary restorations reinforced with particulate glass fibre Objective: The flexural strength and the elastic modulus of acrylic resins, Dencor, Duralay and Trim Plus II, were evaluated with and without the addition of silanised glass fibre. Materials and methods: To evaluate the flexural strength and elastic modulus, 60 test specimens were fabricated with the addition of 10% ground silanised glass fibres for the experimental group, and 60 without the incorporation of fibres, for the control group, with 20 test specimens being made of each commercial brand of resin (Dencor, Duralay and Trim Plus II) for the control group and experimental group. After the test specimens had been completed, the flexural strength and elastic modulus tests were performed in a universal testing device, using the three-point bending test. For the specimens without fibres the One-Way Analysis of Variance and the complementary Tukey test were used, and for those with fibres it was not normal, so that the non-parametric Mann-Whitney test was applied. Results: For the flexural strength test, there was no statistical difference ( p > 0.05) between each commercial brand of resin without fibres [Duralay 84.32(±8.54), Trim plus 85.39(±6.74), Dencor 96.70(±6.52)] and with fibres (Duralay 87.18, Trim plus 88.33, Dencor 98.10). However, for the elastic modulus, there was statistical difference ( p > 0.01) between each commercial brand of resin without fibres [Duralay 2380.64 (±168.60), Trim plus 2740.37(±311.74), Dencor 2595.42(±261.22)] and with fibres (Duralay 3750.42, Trim plus 3188.80, Dencor 3400.75). Conclusion: The result showed that the incorporation of fibre did not interfere in the flexural strength values, but it increased the values for the elastic modulus. [ABSTRACT FROM AUTHOR]