Properties of Epoxy Composites with Halloysite Nanotubes Subjected to Tensile Testing

2021 ◽  
pp. 73-83
Author(s):  
Evgeniya Tkach ◽  
Maxim Bichaev
2020 ◽  
Vol 54 (20) ◽  
pp. 2761-2779 ◽  
Author(s):  
Hasan Ulus ◽  
Halil Burak Kaybal ◽  
Volkan Eskizeybek ◽  
Ahmet Avcı

Seawater aging-dominated delamination failure is a critical design parameter for marine composites. Modification of matrix with nanosized reinforcements of fiber-reinforced polymer composites comes forward as an effective way to improve the delamination resistance of marine composites. In this study, we aimed to investigate experimentally the effect of halloysite nanotube nanoreinforcements on the fracture performance of artificial seawater aged basalt–epoxy composites. For this, we introduced various amounts of halloysite nanotubes into the epoxy and the halloysite nanotube–epoxy mixtures were used to impregnate to basalt fabrics via vacuum-assisted resin transfer molding, subsequently. Fracture performances of the halloysite nanotubes modified epoxy and basalt/epoxy composite laminated were evaluated separately. Single edge notched tensile tests were conducted on halloysite nanotube modified epoxy nanocomposites and the average stress intensity factor (KIC) was increased from 1.65 to 2.36 MPa.m1/2 (by 43%) with the incorporation of 2 wt % halloysite nanotubes. The interlaminar shear strength and Mode-I interlaminar fracture toughness (GIC) of basalt–epoxy hybrid composites were enhanced from 36.1 to 42.9 MPa and from 1.22 to 1.44 kJ/m2, respectively. Moreover, the hybrid composites exhibited improved seawater aging performance by almost 52% and 34% in interlaminar shear strength and GIC values compared to the neat basalt-epoxy composites after conditioning in seawater for six months, respectively. We proposed a model to represent fracture behavior of the seawater aged hybrid composite based on scanning electron microscopy and infrared spectroscopy analyses.


Author(s):  
Wyatt Leininger ◽  
Xinnan Wang ◽  
X. W. Tangpong ◽  
Marshall McNea

In this study, the mechanical properties of multi-walled carbon nanotube (MWCNT) reinforced epoxy composites were characterized using an in-house designed micro/nano tensile load stage in conjunction with an atomic force microscope (AFM). The surface of the nanocomposite was scanned by the AFM during intermittent tensile testing. Micro/nano deformation was observed, and the reinforcing mechanisms were discussed in conjunction with architecture and elastic modulus. Results show that the MWCNT reinforced nanocomposite has an increased elastic modulus. The Halpin-Tsai and Hui-Shia models were compared to the experimental results, and the Halpin-Tsai was found to correlate when only the load bearing outer layer of the MWCNTs were considered. Additionally, it is concluded that the combination of the load stage and AFM is capable of capturing insitu deformation progress for small strain increments.


2017 ◽  
Vol 264 ◽  
pp. 58-61
Author(s):  
Ervina Junaidi ◽  
Mariatti Jaafar ◽  
Sinin Hamdan

In this study, three various types of fillers; pristine multi-walled carbon nanotube (MWCNT), hydroxyl functionalized multi-walled carbon nanotube (MWCNT-OH) and carboxyl functionalized multi-walled carbon nanotube (MWCNT-COOH) were used to prepare epoxy (EP) composites via ultrasonication and casting techniques. The effect of pristine MWCNT and functionalized MWCNT (MWCNT-OH and MWCNT-COOH) and fillers loading (0-1.0 vol%) on tensile properties of EP composites were investigated and compared. To identify the effectiveness of functional groups on the EP composites, the MWCNT, MWCNT-OH and MWCNT-COOH were compared through tensile testing. The addition of pristine MWCNT decreased the material’s tensile strength and modulus, while the addition of MWCNT-OH decreased the material’s tensile strength. However, among the EP composites, the 0.4 vol% MWCNT-COOH/EP composite exhibited a 12.80% increase in tensile strength (44 MPa). The tensile modulus of 0.4 vol% MWCNT-OH/EP and MWCNT-COOH/EP composites were found to be significantly higher compared to unfilled epoxy which were approximately 15.60% (2376 MPa) and 18.54% (2436 MPa) respectively. In conclusion, the MWCNT-COOH/EP composite showed slight improvement in both the tensile strength and modulus. The effect of functionalized MWCNT was supported by morphological analysis, which demonstrated an improvement in MWCNT-COOH dispersion with slightly fine agglomerates particles at 0.4 vol%.


2015 ◽  
Vol 1095 ◽  
pp. 3-7
Author(s):  
Veronika Mušutova ◽  
Petr Tej ◽  
Jiří Kolísko ◽  
Miroslav Černý

This paper is concerned with the evaluation of the parameters of plain weave textile from Kevlar 49 fibers. They were determined following the basic parameters of the textiles e.g. crimp length, crimp amplitude, thickness of the woven fabric, dimensions of the cross-sectional tow (tow width, tow height) and crimp angle. The number of fibers in the warp and tow strands was also determined.The work is also concerned with the analysis of microcracks in the material, that is, microcracks that appeared after the tensile test. Microscopic observation of cracks occurred on the test specimen strip according to DIN EN ISO 14129 for tensile testing. Strips of the material were cut, the metallurgical methods used being kept perpendicular to the thickness of the test specimen. Microcracks occurred in the individual planes located in the chosen reference axis. Microcracks were detected in the entire width of the specimen. The types of microcracks were determined by the length and traits of the microcracks.


2013 ◽  
Vol 22 (7) ◽  
pp. 501-510 ◽  
Author(s):  
Junheng Zhang ◽  
Daohong Zhang ◽  
Aiqing Zhang ◽  
Zhixin Jia ◽  
Demin Jia

In this research, four different concentrations of halloysite nanotubes and carbon nanotubes (0wt%, 0.2 wt%, 0.5 wt% and 1 wt%) were produced using solution casting method. Both fillers were dispersed using bath sonicator for 10 minutes. Flexural properties, surface roughness and microhardness were studied. The highest flexural modulus and flexural strength were observed in the 0.2 wt% HNTs-epoxy composites, where the maximum values were 36.6% and 82% respectively. The maximum surface roughness was recorded in the case of 0.2 wt% HNTs-epoxy composites. The highest microhardness value was found in the 0.5 wt% HNTs-epoxy composites where the microhardness improved by 80%. The results suggest, HNTs were easily dispersed in epoxy matrix than CNTs, at shorter processing time. From the SEM images, it can be observed that, HNTs significantly changed the microstructure of the nanocomposites, as there were many straight and elevated crack lines, this can be associated with the toughening mechanism offered by the filler. CNTs on the other hand, had influenced on the micro cracks and showed semi-parabolic pattern. However, the flexural properties of CNTs are slightly lower than HNTs because CNTs have strong van der Waals force and as a result very difficult to disperse by simple sonication. HNTs can be utilised as an alternative to CNTs, since the dispersion state is better even though at minimum sonication time.


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