scholarly journals Temperature Dependent Strain/Damage Monitoring of Glass/Epoxy Composites with Graphene as a Piezoresistive Interphase

Fibers ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 17 ◽  
Author(s):  
Haroon Mahmood ◽  
Andrea Dorigato ◽  
Alessandro Pegoretti
Keyword(s):  
Graphene Oxide ◽  
Composite Laminates ◽  
Mechanical Performance ◽  
Loss Modulus ◽  
Glass Fibers ◽  
Negative Temperature ◽  
Deposition Process ◽  
Fiber Reinforced Polymer Composites ◽  
Damage Monitoring ◽  
Interlaminar Shear

Graphene as an interphase not only improves the mechanical performance of fiber reinforced polymer composites but also induces functional properties like electrical conductivity, thus providing the possibility of strain monitoring in real time. At this aim, graphene oxide (GO) was electrophoretically deposited at different applied potentials on glass fibers to create a uniform coating and was subsequently chemically reduced to obtain a conductive layer of reduced graphene oxide (rGO). After the optimization of the deposition process, composite laminates were prepared by hand lay-up with an epoxy resin, followed by curing in vacuum bag. The deposited rGO interphase improved the dynamic moduli (storage and loss modulus), the flexural strength (+23%), and interlaminar shear strength (ILSS) (+29%) of the composites. Moreover, laminates reinforced with rGO-coated glass fibers showed an electrical resistivity in the order of ~101 Ω·m, with a negative temperature coefficient. The piezoresistivity of the composites was monitored under flexural loading under isothermal conditions, and strain/damage monitoring was evaluated at different temperatures through the change of the electrical resistance with the applied strain.

scholarly journals Graphene Deposition on Glass Fibers by Triboelectrification

2021 ◽  
Vol 11 (7) ◽  
pp. 3123
Author(s):  
Haroon Mahmood ◽  
Laura Simonini ◽  
Andrea Dorigato ◽  
Alessandro Pegoretti
Keyword(s):  
Graphene Oxide ◽  
Interfacial Shear Strength ◽  
Glass Fibers ◽  
Deposition Process ◽  
Solution Concentration ◽  
Dip Coating ◽  
Slight Improvement ◽  
Reduced Graphene ◽  
Fiber Matrix ◽  
Positively Charged

In this work, a novel nanomaterial deposition technique involving the triboelectrification (TE) of glass fibers (GF) to create attractive charges on their surface was investigated. Through TE, continuous GF were positively charged thus, attracting negatively charged graphene oxide (GO) nanoparticles dispersed in a solution. The electrical charges on the glass fibers surface increased with the intensity of the TE process. The deposited GO coating was then chemically treated to obtain reduced graphene oxide (rGO) on the surface of GFs. The amount of coating obtained increased with the GO solution concentration used during the deposition process, as revealed by FESEM analysis. However, the same increment could not be noticed as a function of the intensity of the process. Both uncoated and coated GF were used to obtain single fiber microcomposites by using a bicomponent epoxy matrix. The fiber/matrix interfacial shear strength was evaluated through micro debonding tests, which revealed an increment of fiber/matrix adhesion up to 45% for rGO coated GF in comparison to the uncoated ones. A slight improvement in the electrical conductivity of rGO coated fibers through TE compared to conventional dip coating was also observed in terms of volumetric resistivity by a four-point probe setup.

Experimental study on the effect of stitch arrangement on mechanical performance of GFRP laminates manufactured on a basis of stitched preforms

2011 ◽  
Vol 46 (9) ◽  
pp. 1067-1078 ◽  
Author(s):  
Mateusz Koziol
Keyword(s):  
Shear Strength ◽  
Composite Laminates ◽  
Mechanical Performance ◽  
Flexural Modulus ◽  
Interlaminar Shear Strength ◽  
Direction Parallel ◽  
Stitch Density ◽  
Stitch Length ◽  
Interlaminar Shear ◽  
Flexural Tests

This article presents the results of interlaminar shear and flexural tests of stitched polyester glass fiber laminates in dependence on stitch density and main geometric stitching parameters: stitch length and stitch spacing. Purpose of the study is to work out guidelines and indications for manufacturers of composite laminates who use or who plan to use stitching technique. It was found that stitching significantly improves interlaminar shear strength which increases with stitch density. However, stitching causes deterioration of in-plane flexural properties – the deterioration progresses when stitch density increases. Obtained results indicate that it is better to achieve increase in stitch density (resulting in improvement of interlaminar shear strength) by reduction of stitch length than by reduction of stitch spacing. Stitched laminate shows higher flexural strength and flexural modulus when bent into direction parallel to the stitch lines than when bent into the transverse direction. The results obtained within the study and their approximation constants may be a base for a new theoretical model simulating behavior of stitched laminate during static bending and enabling prediction of its mechanical performance.

A Comparison of Mechanical and Electrical Properties in Hierarchical Composites Prepared using Electrophoretic or Chemical Vapor Deposition of Carbon Nanotubes

MRS Advances ◽  
2016 ◽  
Vol 1 (12) ◽  
pp. 785-790 ◽  
Author(s):  
Andrew N. Rider ◽  
Qi An ◽  
Narelle Brack ◽  
Erik T. Thostenson
Keyword(s):  
Chemical Vapor Deposition ◽  
Epoxy Resin ◽  
Vapor Deposition ◽  
Composite Laminates ◽  
Mechanical Performance ◽  
Iron Catalyst ◽  
Glass Fibers ◽  
Fiber Surface ◽  
Chemical Vapor ◽  
Hierarchical Composites

ABSTRACTTwo approaches have been employed in the preparation of hierarchical composite laminates with a carbon nanotube (CNT) phase. Glass fibers were coated with CNTs using electrophoretic deposition (EPD) prior to infusion with epoxy resin. The CNTs were functionalized using an ultrasonicated-ozone process followed by reaction with polyethyleneimine (PEI) to enhance CNT to fiber and matrix adhesion. Chemical vapor deposition (CVD) was also used to grow CNTs onto quartz fibers, prior to infusion with an epoxy resin modified with a thermoplastic nanophase. The mechanical performance of the two CNT laminates types were similar, however, the fracture surfaces indicated distinct differences. The EPD laminates showed fracture in the CNT-rich interphase region, whereas, the CVD laminates showed that strength was limited by adhesion failure at the CNT-fiber interface. The electrical conductivity of CVD laminates was 100 times higher than EPD laminates. For the EPD laminates the PEI functionalization increases the CNT-CNT distance resulting in reduced conductivity, while the high CNT packing density and residual iron catalyst on the fiber surface in the CVD laminates creates conducting pathways resulting in higher conductivities.

scholarly journals Silk as a Natural Reinforcement: Processing and Properties of Silk/Epoxy Composite Laminates

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2135 ◽  
Author(s):  
Youssef Hamidi ◽  
M. Yalcinkaya ◽  
Gorkem Guloglu ◽  
Maya Pishvar ◽  
Mehrad Amirkhosravi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Composite Laminates ◽  
Moisture Absorption ◽  
Glass Fibers ◽  
Natural Fibers ◽  
External Pressure ◽  
Silk Fabric ◽  
Interlaminar Shear ◽  
Breaking Energy

With growing environmental awareness, natural fibers have recently received significant interest as reinforcement in polymer composites. Among natural fibers, silk can potentially be a natural alternative to glass fibers, as it possesses comparable specific mechanical properties. In order to investigate the processability and properties of silk reinforced composites, vacuum assisted resin transfer molding (VARTM) was used to manufacture composite laminates reinforced with woven silk preforms. Specific mechanical properties of silk/epoxy laminates were found to be anisotropic and comparable to those of glass/epoxy. Silk composites even exhibited a 23% improvement of specific flexural strength along the principal weave direction over the glass/epoxy laminate. Applying 300 kPa external pressure after resin infusion was found to improve the silk/epoxy interface, leading to a discernible increase in breaking energy and interlaminar shear strength. Moreover, the effect of fabric moisture on the laminate properties was investigated. Unlike glass mats, silk fabric was found to be prone to moisture absorption from the environment. Moisture presence in silk fabric prior to laminate fabrication yielded slower fill times and reduced mechanical properties. On average, 10% fabric moisture induced a 25% and 20% reduction in specific flexural strength and modulus, respectively.

Investigation on cryogenic interlaminar shear properties of carbon fabric/epoxy composites improved by graphene oxide-coated glass fibers

2020 ◽  
Vol 22 ◽  
pp. 100510
Author(s):  
Chen-Yang Dang ◽  
Kun Liu ◽  
Meng-Xuan Fan ◽  
Song-Qing Zhu ◽  
Shuang-Hui Zhao ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Glass Fibers ◽  
Epoxy Composites ◽  
Carbon Fabric ◽  
Shear Properties ◽  
Coated Glass ◽  
Interlaminar Shear

scholarly journals Investigation of Graphene Derivatives on Electrical Properties of Alkali Activated Slag Composites

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4374
Author(s):  
Wu-Jian Long ◽  
Xuanhan Zhang ◽  
Biqin Dong ◽  
Yuan Fang ◽  
Tao-Hua Ye ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Electrical Properties ◽  
Mechanical Performance ◽  
Structural Defects ◽  
Alkali Activated Slag ◽  
Mechanical And Electrical Properties ◽  
Reduced Graphene ◽  
Graphene Derivatives ◽  
Activated Slag ◽  
Alkali Activated

Reduced graphene oxide (rGO) has been widely used to modify the mechanical performance of alkali activated slag composites (AASC); however, the mechanism is still unclear and the electrical properties of rGO reinforced AASC are unknown. Here, the rheological, mechanical, and electrical properties of the AASC containing rGO nanosheets (0, 0.1, 0.2, and 0.3 wt.%) are investigated. Results showed that rGO nanosheets addition can significantly improve the yield stress, plastic viscosity, thixotropy, and compressive strength of the AASC. The addition of 0.3 wt.% rGO nanosheets increased the stress, viscosity, thixotropy, and strength by 186.77 times, 3.68 times, 15.15 times, and 21.02%, respectively. As for electrical properties, the impedance of the AASC increased when the rGO content was less than 0.2 wt.% but decreased with the increasing dosage. In contrast, the dielectric constant and electrical conductivity of the AASC containing rGO nanosheets decreased and then increased, which can be attributed to the abundant interlayer water and the increasing structural defects as the storage sites for charge carriers, respectively. In addition, the effect of graphene oxide (GO) on the AASC is also studied and the results indicated that the agglomeration of GO nanosheets largely inhibited the application of it in the AASC, even with a small dosage.

scholarly journals Cement-Based Materials Containing Graphene Oxide and Polyvinyl Alcohol Fiber: Mechanical Properties, Durability, and Microstructure

Nanomaterials ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 638 ◽  
Author(s):  
Wenguang Jiang ◽  
Xiangguo Li ◽  
Yang Lv ◽  
Mingkai Zhou ◽  
Zhuolin Liu ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Flexural Strength ◽  
Polyvinyl Alcohol ◽  
Mechanical Strength ◽  
Mechanical Performance ◽  
Control Sample ◽  
Corrosion Condition ◽  
Cement Based Materials ◽  
Strength And Durability ◽  
Pva Fiber

The influence of graphene oxide (GO) and polyvinyl alcohol (PVA) fiber on the mechanical performance, durability, and microstructure of cement-based materials was investigated in this study. The results revealed that compared with a control sample, the mechanical strength and durability of cement-based materials were significantly improved by adding PVA fiber and GO. The compressive and flexural strength at 28 d were increased by 30.2% and 39.3%, respectively. The chloride migration coefficient at 28 d was reduced from 7.3 × 10−12 m2/s to 4.3 × 10−12 m2/s. Under a sulfate corrosion condition for 135 d, the compressive and flexural strength still showed a 13.9% and 12.3% gain, respectively. Furthermore, from the Mercury Intrusion Porosimetry (MIP) test, with the incorporation of GO, the cumulative porosity decreased from more than 0.13 cm3/g to about 0.03 cm3/g, and the proportion of large capillary pores reduced from around 80% to 30% and that of medium capillary pores increased from approximately 20% to 50%. Scanning electron microscope (SEM) images showed a significant amount of hydration products adhering to the surface of PVA fiber in the GO and PVA fiber modified sample. The addition of GO coupling with PVA fiber in cement-based materials could promote hydration of cement, refine the microstructure, and significantly improve mechanical strength and durability.

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