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In this study, the researchers aimed to broaden the applications of unsaturated polyester resin (UPR) composites in the building field by incorporating surface-modified titanium dioxide (TiO2) nanoparticles and reinforced chopped glass fibers within the UPR matrix. Specifically, the composites containing 4 wt.% TiO2 nanoparticles and 30 wt.% chopped glass fiber exhibited remarkable properties of 46.1 kJ/m2 in impact strength, 90.1 MPa in flexural strength, 78.8 MPa in tensile strength, and 121.5 °C in heat deflection temperature, which improve 207.5%, 80.3%, 62.5%, and 73.6%, respectively, when compared with the blank sample. Furthermore, the results of the corrosion resistance test showed that the composites performed poorly against polar organic and alkaline solutions, presented good corrosion resistance against acidic media, and behaved relatively stable in the salt solution. [ABSTRACT FROM AUTHOR]

Today, legal regulations, along with social awareness, have made waste management a necessity. Depending on the type of waste, technological developments have enabled an increase in the number of approaches, e.g., reusing, recycling, and manufacturing of different products. In this study, low-density boards were produced using different proportions of office waste paper, wood chips, and chopped E-glass fiber. Waste paper and glass fiber formed the middle layer of the boards and wood chips comprised the surface layers. The density, water absorption, and thickness swelling properties of the boards were investigated. Among the mechanical properties, the modulus of rupture, modulus of elasticity, and internal bond strength were determined. The use of wastepaper led to a reduction in the modulus of rupture and modulus of elasticity of the boards. An increase in the glass fiber ratio contributed positively to the water absorption and thickness swelling properties, whereas it directly led to decreases in the internal bond strength, and the modulus of rupture and modulus of elasticity values. Nonetheless, the low-density boards were able to meet the minimum modulus of rupture and modulus of elasticity specified in ANSI 208.1 standards, while only one variation met the IB requirements.

Copyright of Wood Industry / Drvna Industrija is the property of Drvna Industrija and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Due to their attractive mechanical properties such as higher strength-to-weight and stiffness-to-weight ratios, instead of conventional isotropic materials, Fiber Reinforced Polymer (FRP) cylindrical shells are being increasingly used in various engineering applications such as aerospace, oil tanks, liquid storage vessels, and silos. Cylindrical shells may experience axial compression load due to primary loading conditions. For a shell with a closed roof, axial compression load is caused by the weight of the roof. In addition, many shells under other loading conditions can also induce either symmetrical or unsymmetrical axial compression loads. The buckling and failure analysis of cylindrical shells made of composite materials is a complex task when compared to the cylindrical shells made of isotropic materials. There are two main failure modes in the composite cylindrical shells subjected to axial compression load, one associated with material strength of the cylinder wall and the other with buckling of the cylinder wall. This study deals with the behavior of chopped Glass Fiber Reinforced Polymer (GFRP) cylindrical shells subjected to axial compression load with an experimental and numerical procedure. Three specimens were used with the same R/t ratio. In the laboratory, the axial compression load was applied by a vertical hydraulic jack. In order to measure the deformation of the cylindrical specimens during the loading, four Linear Voltage Differential Transformers (LVDTs) were used. The nonlinear static analysis method (Riks) using the ABAQUS/Standard software has been employed, considering the boundary and geometric imperfections. For modelling the cylindrical specimens shells, the four-node quadrilateral element (S4R) was used. The critical load and failure mode were determined using Hashin's failure criteria. The effects of the L/R ratio on these shells are examined. Results indicate that the failure mode of these specimens was material failure because of high thickness-to-radius ratio. In addition the stiffness of the cylindrical shell specimens decreases with increasing the height. The comparison between the experimental results and Finite Element Analysis (EFA) exhibited acceptable adaptation.

In this study, the researchers aimed to broaden the applications of unsaturated polyester resin (UPR) composites in the building field by incorporating surface-modified titanium dioxide (TiO2) nanoparticles and reinforced chopped glass fibers within the UPR matrix. Specifically, the composites containing 4 wt.% TiO2 nanoparticles and 30 wt.% chopped glass fiber exhibited remarkable properties of 46.1 kJ/m2 in impact strength, 90.1 MPa in flexural strength, 78.8 MPa in tensile strength, and 121.5 °C in heat deflection temperature, which improve 207.5%, 80.3%, 62.5%, and 73.6%, respectively, when compared with the blank sample. Furthermore, the results of the corrosion resistance test showed that the composites performed poorly against polar organic and alkaline solutions, presented good corrosion resistance against acidic media, and behaved relatively stable in the salt solution.

Rubber-based conductive composites are widely used in sensors, wearable electronic devices and electromagnetic fields. In this work, by using the two-roll milling and hot-pressing process, chopped glass fiber (CGF) and graphene (Gr) as additives, and acrtlinitrile-brtadiene rubber (NBR) as the matrix, a series of anisotropic flexible rubber-based composites were prepared. Using this preparation method, both CGF and Gr additives were directly arranged in the material. When the content of CGF was 1 wt.%, the tensile strength in both the T and W directions of the material reached 27 MPa and 28 MPa, respectively. When the content of CGF was fixed at 1 wt.% and Gr was 1.5 wt.% and the elongation at break in both directions reached 328% and 347%. By focusing on the comparison of the dielectric differences in the T and W directions in the X band, it was found that the directional arrangement of the additives led to differences in the dielectric properties. [ABSTRACT FROM AUTHOR]

The paper presents a novel kind of carbon foam composites reinforced by chopped glass fibers. Microstructure, mechanical properties and thermal insulation of the composites have been investigated by scanning electron microscopy, universal testing machine and laser thermal constant analyzer, respectively. Results showed that carbon foam composites had a spherical and closed-cell structure; chopped glass fibers were uniformly distributed in the carbon matrix along different directions. The mechanical properties exhibited optimum with the 7% glass fiber additives, 11.27 MPa of shear strength, higher than that of pure carbon foams by as much as 111%. Compressive and shear fracture were both characterized by gradient brittleness. Many tiny open-pores existed in carbon foams with a certain amount of glass fiber additives, giving rise to the higher thermal conductivity. Nevertheless, carbon foam composites possessed good thermal insulation, 0.311 W·m−1·K−1 at room temperature, and 1.04 W·m−1·K−1 in 800 °C at the most. [ABSTRACT FROM AUTHOR]

Copyright of China Plastics / Zhongguo Suliao is the property of Journal Office of CHINA PLASTICS and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

• To investigate chopped glass fiber (CGF) reinforced polymer concretes (CGFRPCs) • To evaluate the effect of excessive fiber reinforcement. • To obtain the detailed information about the CGFRPCs by using scanning electron microscope. • To investigate the mechanical properties of the CGFRPCs. Polymer concretes (PCs) have evolved with the growing need for special concretes in the construction sector such as swimming pools, sewer structures, drainage channels, reinforcement injection, and other structures that contain liquids or corrosive chemicals. Recently, these concretes have been prioritized and their importance is growing. In this study, chopped glass fiber (CGF) reinforced polymer concretes (CGFRPCs) are emphasized and the effect of excessive fiber reinforcement on the mechanical properties of concrete is investigated. In this regard, six different mixtures; M1 (Pure PC), M2 (0.15 % CGFs), M3 (0.20 % CGFs), M4 (0.25 % CGFs), M5 (0.50 % CGFs), M6 (1.0 % CGFs); were prepared by considering 0, 0.6, 0.8, 1, 2 and 4 reinforcing indexes (RIs) with a constant aspect ratio (6/0.015 = 400), respectively. Then, the initial setting time, final setting time, peak temperature and flow tests are performed on the fresh concrete samples. The density, flexural strength and compressive strength at 7, 14, 21 and 28 days are determined on the prism and cube samples as the hardened concrete tests. Besides, scanning electron microscope (SEM) examinations are performed to obtain detailed information about the behavior of the concretes. The experimental studies and SEM evaluations show that excessive fiber reinforcement negatively affects both fresh concrete properties and hardened concrete properties because of fiber agglomeration, thixotropy, fiber pull-out, fiber breakage, dislodged aggregate, interface and matrix cracks. In addition, it is observed that the problems observed in the CFRPCs increase as the RI increases. [ABSTRACT FROM AUTHOR]

This paper aims to presents the investigations made on the effect of impact response of chopped glass fiber–epoxy nanocomposite laminates subjected to low velocity impact using instrumented falling weight impact tests. The laminates were prepared using six layers of chopped strand mat with density of 610 gsm with epoxy resin and nanoclay content varied from 1, 3, and 5 wt%, by hand lay-up method. The nanoclay was dispersed into the epoxy by high shear mixing process in order to obtained uniform distribution of individual nanoclay. Laminates were impacted at constant mass with different impact energies. During these low velocity impact tests, the maximum load, absorbed energy, and deflection at peak load were recorded. It was observed that by dispersion of nanoclay as reinforcement, there was significant improvement in load carrying capacity and energy absorption. When a small amount of nanoclay (1 wt%) was added into the epoxy, the maximum load was enhanced by 20%. The presence of stiffer nanoclay significantly reduced the surface cracks propagation and controlled delamination area. Scanning electron microscopy was performed to characterize the damage progression. [ABSTRACT FROM PUBLISHER]

Abstract: Polyurethane (PU) adhesive is widely used for bonding the secondary barrier of cryogenic containment systems (CCS) of liquefied natural gas (LNG) ships due to its ductility at room temperature, although it can become brittle at the cryogenic temperature below its glass transition temperature. To evaluate the reliability of PU adhesive at the cryogenic temperature of −150°C, the fracture toughness of double-cantilever-beam (DCB) adhesive joints composed of stainless steel and aluminum adherends was measured. Because the fracture toughness of the PU adhesive was found to be very low at the cryogenic temperature, the adhesive was reinforced with chopped glass fibers. The fracture toughness with respect to the length and volume fraction of the chopped glass fibers was then measured. Based on the experimental results, an optimal reinforcement method is suggested for the reliable application of PU adhesive at cryogenic temperatures. [Copyright &y& Elsevier]

Abstract: Liquefied natural gas (LNG) is mainly carried by membrane type LNG ships, whose cargo containment system is composed of dual tightness barriers and two insulation boards. The insulation board should have not only cryogenic reliability against thermal load, but also high thermal insulation performance for safe and efficient transportation of LNG. Although polyurethane foam (PUF) has been widely used for the insulation board due to its low production cost and relatively good thermal and mechanical properties, the cryogenic reliability of PUF is a remaining concern in marine fields due to its brittleness at cryogenic temperatures. In this work, the PUF was reinforced with chopped E-glass fiber because of its good dispersion and distribution characteristics. The compression, tension and the fracture toughness test were conducted with respect to the amount of the chopped E-glass fiber both at the room (25°C) and cryogenic (−150°C) temperatures. From the experimental results, it was found that the chopped E-glass fiber reinforcement increased the fracture toughness of the PUF much, especially at the cryogenic temperature. Therefore, the PUF reinforced with chopped glass fibers will improve much the reliability of the LNG cryogenic containment system during the voyage of LNG ships. [Copyright &y& Elsevier]