Frictional characteristics of glass fiber reinforced polymer (GFRP) composites are of technological interests for reducing wear in circumstances where they are applied. Graphene oxide (GO) is one 2D ...nanomaterial with an excellent lubricating effect. However, no work has been reported yet on the effects of GO coating on the frictional characteristics of GFRP composites. In this work, GO was grafted on GFs by a surface treatment method via silane coupling agent. Uncoated and coated unidirectional GF reinforced epoxy composites were prepared using a hot press process. The frictional characteristics of GF reinforced composites were investigated in two directions parallel and perpendicular to fiber direction by the pin-on-disk method under the pressure of 5–30 N at the disk rotating speed of 50–200 rpm. The results showed that the frictional stability was greatly improved by grafting GO on GFs. The friction coefficient of GO-coated glass fiber reinforced polymer (GO-coated GFRP) composite was generally lower than that of the GFRP composite under a low pressure of 5 N and showed the lowest average friction coefficient of about 0.10 at the rotating speed of 100 rpm in the direction parallel to the fiber alignment. For the raw glass fiber reinforced composite, the friction coefficient is high under low pressures at low rotation speeds while this tendency is inverse for the GO-coated GFRP composite. In addition, the anisotropy of the friction characteristics is not obvious under low pressures but becomes obvious at high pressures for both GFRP and GO-coated GFRP composites.
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The composite materials are replacing the traditional materials, because of its superior properties such as high tensile strength, low thermal expansion, high strength to weight ratio. The ...developments of new materials are on the anvil and are growing day by day. Natural fiber composites such as sisal and jute polymer composites became more attractive due to their high specific strength, lightweight and biodegradability. Mixing of natural fiber with Glass-Fiber Reinforced Polymers (GFRPs) are finding increased applications. In this study, sisal–jute–glass fiber reinforced polyester composites is developed and their mechanical properties such as tensile strength, flexural strength and impact strength are evaluated. The interfacial properties, internal cracks and internal structure of the fractured surfaces are evaluated by using Scanning Electron Microscope (SEM). The results indicated that the incorporation of sisal–jute fiber with GFRP can improve the properties and used as a alternate material for glass fiber reinforced polymer composites.
In this study, a preliminary finding is carried out to obtain the optimum E‐glass fiber content in polypropylene (PP) plastic products using loadings of 5, 10, 20, 30, and 40 wt%. The formulation ...with the optimum loading of 10 wt% glass fiber was reprocessed 10 times via extrusion and compression molding techniques to simulate actual recycling and impacts on service life properties such as mechanical, toughness, chemical, thermal, composition, and morphology. In the result, mechanical properties were lost after each reprocessing without effect on the chemical properties and elemental compositions. The thermal studies showed a decrease in degradation temperatures with the onset degradation temperature (TOnset) for the one‐time reprocessed PP recorded at 336.93°C with a maximum rate of weight loss (TMax) at 427.68°C which further reduced to 259.90°C (TMax of 388.47°C) after 10 extrusion run showing one‐step decomposition patterns. This work provides that glass fiber‐reinforced plastics should not be reprocessed beyond 3 times except when refreshed with the addition of virgin PP to make up for the lost property. This will be very useful for manufacturers who want to simultaneously save costs (retain profit margin) and maintain the environment.
Illustration of the recycling process for glass fiber and Isotactic polypropylene composites for ten reprocessing cycles and the study of their mechanical, thermal, and morphological properties.
Glass fiber‐reinforced epoxy resin composite materials are widely used in various fields because of their excellent properties, especially in the stringent performance requirements of wind turbine ...blades manufacture for wind power generation. However, the irreversible cross‐linking network of the epoxy resin makes it difficult to recycle. In recent years, the management of large amounts of decommissioned wind turbine blade waste has become spotlight. This study used self‐developed solid‐state shear milling technology to effectively remove the epoxy resin from the glass fiber surface while preserving its high aspect ratio, ensuring its mechanical reinforcement potential. Furthermore, this process also significantly reduced epoxy resin particle size. Subsequently, composites with filler contents up to 50 wt.% were formulated with polypropylene. In the optimized composition, the material exhibited a remarkable 37.1% increase in tensile strength, 147.3% increase in modulus, and 63.8% increase in flexural strength, 165.5% in modulus, respectively. In this research, we conducted a comprehensive exploration into the effects of modifier structure and powder content on different properties of composites, contributing to a deeper understanding of these key factors.
Resource utilization of wind turbine blades.
Three-dimensional nondestructive location of defects, such as delaminations, in glass fiber-reinforced polymer (GFRP) laminates remains a challenge. Terahertz techniques have shown promise, but their ...success relies on advanced signal-processing techniques applied to the raw data. The current work presents an advance in the quantitative three-dimensional nondestructive location of delaminations in GFRP laminates. Namely, terahertz time-of-flight tomography, together with adaptive sparse deconvolution based on a two-step iterative shrinkage-thresholding algorithm, as well as the Canny edge-detection operator, are employed in nondestructive measurement of layer thicknesses and to extract the edges of delaminations in GFRP laminates. Compared with the commonly used frequency wavelet-domain deconvolution method or previous implementations of sparse deconvolution, the adaptive sparse deconvolution approach provides a clearer and rapid stratigraphic reconstruction of GFRP laminates while yielding accurate thickness information for each resin layer and low sensitivity to noise. In addition, the proposed edge-detection algorithm presents better performance in estimating the transverse size of delaminations, compared to the common −6 dB drop approach. Finally, our experiments verify the effectiveness of the proposed signal and image processing approaches for three-dimensional localization of delamination defects in GFRP laminates and the quantitative characterization of layer thickness.
This study's aim was to research the ultimate loads and failure modes of single‐bolted pultruded glass‐fiber‐reinforced polymer (PGFRP) connections reinforced by glass fiber sheets (GFSs) under ...pin‐bearing conditions. In total, 144 specimens with various geometric parameters of GFRP bolted connections with different ratio values of the end distance of PGFRP plate to bolt diameter (e/d) and various ratio values of width of PGFRP plate to bolt diameter (w/d) were considered, and their results are here discussed (e/d = 2,3,4 and w/d = 2,3,4,5). Three types of GFSs (0°/90° GFSs, ±45°GFSs, and chopped strand mat GFSs) were molded by the vacuum‐assisted resin transfer molding (VaRTM) method and used to strengthen the connections. The results show that all three types of GFSs had good effects on the increase in the ultimate load of the connections. In addition, the strengthening effects were decreased with the increase in the e/d ratio of the connections for all types of GFSs. Moreover, theoretical equations were suggested to forecast the ultimate loads and failure modes of pin‐bearing single GFS‐strengthened PGFRP connections with high accuracy (less than 12% deviation).
An experimental study was conducted to investigate anisotropy effects on tensile properties of two short glass fiber reinforced thermoplastics. Tensile tests were performed in various mold flow ...directions and with two thicknesses. A shell–core morphology resulting from orientation distribution of fibers influenced the degree of anisotropy. Tensile strength and elastic modulus nonlinearly decreased with specimen angle and Tsai–Hill criterion was found to correlate variation of these properties with the fiber orientation. Variation of tensile toughness with fiber orientation and strain rate was evaluated and mechanisms of failure were identified based on fracture surface microscopic analysis and crack propagation paths. Fiber length, diameter, and orientation distribution mathematical models were also used along with analytical approaches to predict tensile strength and elastic modulus form tensile properties of constituent materials. Laminate analogy and modified Tsai–Hill criteria provided satisfactory predictions of elastic modulus and tensile strength, respectively.
•Moisture uptake of FRPs (except BFRP) followed: NC > SWSSNC > DW > HPC > SWSSHPC.•The presence of NaCl in simulated concrete led to a less FRPs moisture uptake.•Simulated high performance concrete ...solution leads to less degradation of FRP.•Greater basalt fiber degradation in SWSSC might due to the reaction of Al, Fe, and Mg with alkali and Cl− ions.•CFRP exhibited the best durability in SWSSC, followed by GFRP and then BFRP.
This paper presents an experimental investigation on the degradation of carbon/glass/basalt fiber reinforced polymer (i.e., CFRP/BFRP/GFRP) exposed to simulated seawater sea sand concrete environments (SWSSC) at 25, 40 and 60 °C for 6 months. The presence of NaCl in simulated concrete environment was found beneficial for the moisture uptake of CFRP and GFRP. The greater fiber degradation of BFRP was attributed to its high aluminium, iron and magnesium contents on fibers. Further, FRPs showed greater degradation resistance in high performance concrete solutions that have a lower alkaline content. Thus, CFRP exhibited the best durability to simulated SWSSC environments, followed by GFRP and BFRP.
Polymers tend to have low surface free energy, a significant cause of adhesion properties with other substances. Plasma treatment is an optimal method to improve surface properties. This work used a ...recycled glass fiber‐polymer coating, and another based on Nylon 6,6. The surface modification of both layers was carried out with an atmospheric plasma treatment at different times. Chemical analysis of the plasma treated and the untreated surface were analyzed by infrared spectroscopy and X‐ray diffraction. Atomic force microscopy (AFM) investigated the morphology and topography surface. The plasma treatment results improve wettability and surface free energy. The contact angle decreases for Nylon 6,6 from 68° to 0° and for glass fiber‐polymer from 56° to 18°. However, the wettability remains over time in Nylon 6,6 layer, and the composite material reverts in 15 days. The high surface free energy after plasma treatment was mainly due to an increase in the polar component by inserting polar groups. The % crystallinity increases with plasma treatment due to the loss of the amorphous part of the polymer by plasma etching. AFM analysis shows an improvement in the roughness surface after treatment. These results greatly interest in enhancing adhesion with other substrates.
Abstract
Utilizing fibre-reinforced concrete is still a difficulty for present engineers. Generally, it is acknowledged that the mechanical, cracking and fracture qualities of fibre-reinforced ...concrete are much better than those of conventional concrete. The addition of fibres to the concrete matrix mitigates its fragility. Typically, short fibres are utilised in concrete to prevent cracks caused by drying and autogenous shrinkage. Currently, there is a substantial increase in the use of short alkali-resistant glass fibres. This experiment was conducted to examine the influence of glass fibre reinforcement on the compressive and flexural behaviour of concrete. This research investigates the characteristics of glass fibres reinforced concrete (GFRC) after 7 and 28 days of curing, such that GFRC may be employed in construction. Concrete containing short alkali-resistant glass fibres of 36 mm in length and 1% volume fraction (VF) was developed for this purpose. The testing findings revealed that the average compressive strength of GFRC after 28 days of curing was 72.06 MPa. The flexural properties of GFRC are determined, and the 7-day and 28-day average bending strengths of GFRC concrete samples are 6.46 MPa and 7.94 MPa, respectively, indicating that GFRC responds well under loading conditions.
