Moisture Effect on Mechanical Properties of Graphene/Epoxy Nanocomposites

2016 ◽  
Vol 32 (6) ◽  
pp. 673-682 ◽  
Author(s):  
H.-K. Liu ◽  
Y.-C. Wang ◽  
T.-H. Huang

Abstract2-D graphene nanosheets (GNS) not only have superior mechanical properties, but stacking of GNS in composites is expected to inhibit moisture absorption. In this paper, moisture effect on tensile strength of graphene/epoxy nanocomposites is investigated. Two kinds of graphene reinforcements are used including graphene oxide (GO) and reduced graphene oxide (RGO) with reinforcement weight fraction WGO or WRGO in the range of 0.5 to 3.0wt%. A dispersion agent acetone is added in nanocomposites to enhance graphene dispersion. To evaluate moisture influence, those nanocomposites are soaked in two kinds of liquid including deionized water (DIW) and salt water (saline solution) for seven kinds of soaking periods of time including 24, 48, 72, 100, 400 hours, 30 days, and 60 days. After soaking test, diffusion coefficients of various composites are evaluated; besides tensile strengths of composites are measured by microforce testing machine. In order to correlate the strength with microstructure evolution, several techniques are adopted to analyze morphologies and functionalities of reinforcements and fracture surface of composites. They include Raman spectroscope, X-ray photoelectron spectroscope, and SEM. 2-D GNS are found to effectively enhance nanocomposites by moisture attack, and their corresponding reinforcing mechanisms are proposed.

2021 ◽  
Vol 55 (6) ◽  
Author(s):  
Vinu kumar Shettahalli Mantaiah ◽  
C. Sasikumar ◽  
E. Sakthivelmurugan ◽  
J. P. Rishi

In this investigation four varieties of plain derived-irregular basket-woven-flax fabric-reinforced epoxy (F-E) composites pre-treated with alkali and trimethoxymethylsilane (ATS) were prepared with a hand lay-up process by varying their weight fraction of fiber loadings (0; 25; 35; 45) w/%. A water-absorption test (salt water) as per ASTM D 570-98 was performed over the fabricated composites and studied its consequences on their static mechanical properties (such as tensile, flexural, impact and interlaminar shear strength) in accordance with the ASTM standards. The results revealed that salt-water-soaked ATS-treated F-E composites exhibited poorer mechanical properties than unsoaked ones. Moreover, this study elaborated the kinetics of water absorption and showed that the moisture-absorption rate depends on the weight fraction of fibre content. Furthermore, scanning electron microscopy (SEM) disclosed fiber splittings and severe damage at the fiber-matrix interface as experienced by soaked F-E composites.


2009 ◽  
Vol 23 (06n07) ◽  
pp. 1377-1382 ◽  
Author(s):  
SEULKI PARK ◽  
JINMYUNG CHOI ◽  
BONGGYU PARK ◽  
IKMIN PARK ◽  
YONGHO PARK ◽  
...  

Hypereutectic Al - Si alloys with fine and evenly distributed Si precipitates have superior mechanical properties In this study, hypereutectic Al - Si alloy powders which contained 15 and 20wt% Si were prepared by a gas atomization process. 1, 3 and 5wt% AlN particles were blended with the Al - Si alloy powders using turbular mixer. The mixture was consolidated by Hot Press at 550°C for 1h under 60MPa. Relative density of the sintered samples was about 98% of theoretical density. This study was investigated by two ways. One is the effect of reinforcement weight fraction and the other is the effect of Silicon contents on the mechanical properties of the composite. Microstructural characterization and phase evaluation were carried out using X-ray Diffraction, Scanning Electron Microscopy equipped with Energy Dispersive Spectrometer. The results showed that the smaller the reinforcement particle size was and the better its distribution was, the higher ultimate tensile strength and hardness were.


2018 ◽  
Vol 3 (1) ◽  
pp. 427-438
Author(s):  
Jake D. Nunemaker ◽  
Michael M. Voth ◽  
David A. Miller ◽  
Daniel D. Samborsky ◽  
Paul Murdy ◽  
...  

Abstract. Fiber-reinforced-polymer composites (FRPs) possess superior mechanical properties and formability, making them a desirable material for construction of large optimized mechanical structures, such as aircraft, wind turbines, and marine hydrokinetic (MHK) devices. However, exposure to harsh marine environments can result in moisture absorption into the microstructure of the FRPs comprising these structures and often degrading mechanical properties. Specifically, laminate static and fatigue strengths are often significantly reduced, which must be considered in design of FRP structures in marine environments. A study of fiberglass epoxy unidirectional and cross-ply laminates was conducted to investigate hygrothermal effects on the mechanical behavior of a common material system used in wind applications. Several laminates were aged in 50 ∘C distilled water until maximum saturation was reached. Unconditioned control and the saturated samples were tested in quasi-static tension with the accompaniment of acoustic emission (AE) monitoring. Cross-ply laminates experienced a 54 % reduction in strength due to moisture absorption, while unidirectional laminate strengths were reduced by 40 %. Stress–strain curves and AE activity of the samples were analyzed to identify changes in damage progression due to aging.


RSC Advances ◽  
2018 ◽  
Vol 8 (19) ◽  
pp. 10573-10581 ◽  
Author(s):  
Laiyun Wei ◽  
Xuan Fu ◽  
Mingchao Luo ◽  
Zhengtian Xie ◽  
Cheng Huang ◽  
...  

Graphene oxide (GO) and carbon nanotube (CNT) hybrid fillers were used to replace partial carbon black (CB), and GO/CNT/CB/NR composites were prepared with excellent crack growth resistance, low heat build-up and superior mechanical properties.


Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1116 ◽  
Author(s):  
Maoyuan Li ◽  
Peng Chen ◽  
Bing Zheng ◽  
Tianzhengxiong Deng ◽  
Yun Zhang ◽  
...  

Due to its superior mechanical properties, graphene (Gr) has the potential to achieve high performance polymer-based nanocomposites. Previous studies have proved that defects in the Gr sheets could greatly reduce the mechanical properties of Gr, while the Stone-Wales (SW) defect was found to enhance the interfacial mechanical strength between Gr and epoxy. However, the combined effects of defects on the overall mechanical properties of Gr/epoxy nanocomposites have not been well understood. In this paper, the effect of the SW defect on the mechanical properties of Gr/epoxy nanocomposites was systematically investigated by using molecular dynamic simulations. The simulation results showed that the SW defect would degrade the mechanical properties of nanocomposites, including the Young’s modulus and in-plane shear modulus. Surprisingly, the transverse shear modulus could be remarkably enhanced with the existence of SW. The reinforcing mechanisms were mainly due to two aspects: (1) the SW defect could increase the surface roughness of the Gr, preventing the slippage between Gr and epoxy during the transverse shea; and (2) the nanocomposite with defective Gr enables a higher interaction energy than that with perfect graphene. Additionally, the effects of temperature, the dispersion and volume fraction of Gr were also investigated.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Joo Hyung Lee ◽  
Seong Hun Kim

Abstract Incorporation of nanofillers into polyurethane (PU) is a promising technique for enhancing its thermal and mechanical properties. Silane grafting has been used as a surface treatment for the functionalization of graphene oxide (GO) with numerous reactive sites dispersed on its basal plane and edge. In this study, amine-grafted GO was prepared using silanization of GO with (3-aminopropyl)triethoxysilane. The functionalized graphene oxide (fGO) was characterized by Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy. Next, it was introduced in PU fabricated using polycaprolactone diol, castor oil, and hexamethylene diisocyanate. The fGO–PU nanocomposites were in turn characterized by FT-IR, X-ray diffraction, scanning electron microscopy, differential scanning calorimetry, thermogravimetric analysis, and a universal testing machine. The results obtained from these analyses showed changes in structural thermal properties, as well as improved thermal stability and mechanical properties because of the strong interfacial adhesion between the fGO and the PU matrix.


MRS Advances ◽  
2020 ◽  
Vol 5 (25) ◽  
pp. 1305-1312
Author(s):  
J. A. Panashe ◽  
Y. Danyuo

AbstractThis paper presents a recent study on recycling poly-ethylene-tetraphylate (PET), known as plastic waste material in Ghana, to wealth. Composites were produced by heating aggregates together with shredded PET plastic waste material, while bitumen was added to the plastic-coated aggregates. The composites produced were reinforced with 4.5 wt%, 9.0 wt%, 13.6 wt%, and 18.0 wt% PET. Mechanical properties of the fabricated composite samples were studied with a Universal testing machine for optimization. The work demonstrated that shredded PET plastic waste material acts as a strong binding agent for bitumen that can improve on the shelf life of the asphalt. From the results, 13.6 wt% concentration of PET was shown to experience the maximum compressive strength and flexural strength. Besides, water resistance was shown to increase with PET concentrations/weight fraction. From the data characterized 13.6 wt% of PET plastic gives the optimum plastic concentration that enhances the rheological properties of bitumen. The implications of the result are therefore discussed for the use of 13.6 wt% PET in road construction.


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