Improved Interlaminar Shear Behaviour of a New Hybrid Kevlar/Cocos Nucifera Sheath Composites with Graphene Nanoplatelets Modified Epoxy Matrix

This research investigated the effect of adding different wt.% (0, 0.25, 0.50, and 0.75) of GNP (graphene nanoplatelets) to improve the mechanical and moisture resistant properties of Kevlar (K)/cocos nucifera sheath (CS)/epoxy hybrid composites. The laminates were fabricated with different K/CS weight ratios such as 100/0 (S1), 75/25 (S2), 50/50 (S3), 25/75 (S4), and 0/100 (S5). The results revealed that the addition of GNP improved the tensile, flexural, and impact properties of laminated composites. However, the optimal wt.% of GNP varies with different laminates. A moisture diffusion analysis showed that the laminates with a 0.25 wt.% of GNP content efficiently hindered water uptake by closing all the unoccupied pores inside the laminate. Morphological investigations (SEM and FE-SEM (Field Emission Scanning Electron Microscope)) proved that the addition of GNP improved the interfacial adhesion and dispersion. Structural (XRD and FTIR) analyses reveals that at 0.25 wt.% of GNP, all the hybrid composites showed a better crystallinity index and the functional groups presents in the GNP can form strong interactions with the fibers and matrix. A statistical analysis was performed using One-way ANOVA, and it corroborates that the mechanical properties of different laminates showed a statistically significant difference. Hence, these GNP-modified epoxy hybrid composites can be efficiently utilized in load-bearing structures.

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The Mechanical Properties of Organic Modified Epoxy Resin

The Annals of “Dunarea de Jos” University of Galati. Fascicle IX, Metallurgy and Materials Science ◽

10.35219/mms.2020.3.02 ◽

2020 ◽

Vol 43 (3) ◽

pp. 10-14

Author(s):

Georgel MIHU ◽

Claudia Veronica UNGUREANU ◽

Vasile BRIA ◽

Marina BUNEA ◽

Rodica CHIHAI PEȚU ◽

...

Keyword(s):

Mechanical Properties ◽

Composite Materials ◽

Epoxy Resin ◽

Epoxy Matrix ◽

Epoxy Resins ◽

Mechanical Tests ◽

Organic Modification ◽

Three Point Bending ◽

Modified Epoxy

Epoxy resins have been presenting a lot of scientific and technical interests and organic modified epoxy resins have recently receiving a great deal of attention. For obtaining the composite materials with good mechanical proprieties, a large variety of organic modification agents were used. For this study gluten and gelatin had been used as modifying agents thinking that their dispersion inside the polymer could increase the polymer biocompatibility. Equal amounts of the proteins were milled together and the obtained compound was used to form 1 to 5% weight ratios organic agents modified epoxy materials. To highlight the effect of these proteins in epoxy matrix mechanical tests as three-point bending and compression were performed.

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Directional Interlaminar Shear Strength (ILSS) of nano-modified epoxy/unidirectional glass fibre composite

AIMS Materials Science ◽

10.3934/matersci.2018.4.603 ◽

2018 ◽

Vol 5 (4) ◽

pp. 603-613

Author(s):

M. Rajanish ◽

◽

N. V. Nanjundaradhya ◽

Ramesh S. Sharma ◽

H. K. Shivananda ◽

...

Keyword(s):

Shear Strength ◽

Glass Fibre ◽

Fibre Composite ◽

Interlaminar Shear Strength ◽

Unidirectional Glass ◽

Interlaminar Shear ◽

Modified Epoxy ◽

Glass Fibre Composite

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Experimental studies on interlaminar shear strength and dynamic mechanical analysis of luffa fiber epoxy composites with nano PbO addition

Journal of Industrial Textiles ◽

10.1177/15280837211052317 ◽

2021 ◽

pp. 152808372110523

Author(s):

Kumaresan Gladys Ashok ◽

Kalaichelvan Kani

Keyword(s):

Shear Strength ◽

Dynamic Mechanical Analysis ◽

Epoxy Matrix ◽

Weight Percent ◽

Mechanical Analysis ◽

Interlaminar Shear Strength ◽

Epoxy Composites ◽

Dynamic Mechanical ◽

Interlaminar Shear ◽

Composite Samples

In the present study, the significance of nanofiller lead oxide (PbO) on the dynamic mechanical analysis (DMA) and interlaminar shear strength (ILSS) performance of luffa fiber–reinforced epoxy composites was investigated. The epoxy matrix was altered with nanofiller PbO of different weight percent through a mechanical stirring process. The PbO-added luffa fiber epoxy composites were made through hand layup preceded by the compression molding method. The prepared composite samples were investigated for ILSS and DMA. The test results lead to the inference that the 1.25 wt% PbO nanofiller–added composite samples attained 25%, 17%, and 55% of higher loss modulus, storage modulus, and ILSS, respectively, as compared with the other prepared samples. The morphological investigation was conducted on the fractured surface of the interlaminar tested samples. The micrographic images show the bonding nature of the luffa fiber with the epoxy matrix, fiber breakage, and fiber pullouts. The characterization studies such as FTIR, XRD, and EDX were conducted on the fabricated composite samples. The XRD studies show that the rise in weight percent of the nanofiller PbO enhances the crystallinity of the composite samples. Moreover, the composite sample prepared with 1.25 wt% nanofiller PbO can be used to prepare low-cost roofing materials for sustainable housing projects.

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PPG-Terminated Tetra-Carbamates as the Toughening Additive for Bis-A Epoxy Resin

Polymers ◽

10.3390/polym11091522 ◽

2019 ◽

Vol 11 (9) ◽

pp. 1522

Author(s):

Ming Zhang ◽

Mingqing Chen ◽

Zhongbin Ni

Keyword(s):

Epoxy Resin ◽

Epoxy Matrix ◽

Microphase Separation ◽

Intramolecular Interactions ◽

Hexamethylene Diisocyanate ◽

Separation Mechanism ◽

Toughening Mechanism ◽

The Impact ◽

Modified Epoxy ◽

Epoxy Systems

We synthesized PPG-terminated tetra-carbamates as a new toughening additive for epoxy thermosets through facile addition reaction of hexamethylene diisocyanate (HDI) with poly(tetra-methylene glycols) (PTMG) and poly(propylene glycols) (PPG). The effects of prepared tetra-carbamates on the rheological behavior of neat epoxy resin were studied along with the various cured properties of their modified epoxy systems. Four carbamate groups (–NHCOO–) endow the prepared additives not only with good intramolecular interactions, but also with optimal intermolecular interactions with epoxy polymers. This results in the suitable miscibility of the additives with the epoxy matrix for the formation of the typical biphasic structure of microparticles dispersed in the epoxy matrix via polymerization-induced microphase separation. The impact strength and critical stress concentration factor (KIC) of cured modified epoxy systems with the additives are significantly higher than those of unmodified epoxy systems, without sacrificing the processability (Tg) and flexural strength. The toughening mechanism is understood as a synergism combination among the phase separation mechanism, the in situ homogeneous toughening mechanism, and the particle cavitation mechanism.

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Halloysite nanotube reinforcement endows ameliorated fracture resistance of seawater aged basalt/epoxy composites

Journal of Composite Materials ◽

10.1177/0021998320902821 ◽

2020 ◽

Vol 54 (20) ◽

pp. 2761-2779 ◽

Cited By ~ 4

Author(s):

Hasan Ulus ◽

Halil Burak Kaybal ◽

Volkan Eskizeybek ◽

Ahmet Avcı

Keyword(s):

Shear Strength ◽

Hybrid Composites ◽

Tensile Tests ◽

Halloysite Nanotubes ◽

Interlaminar Shear Strength ◽

Epoxy Composites ◽

Halloysite Nanotube ◽

Fiber Reinforced Polymer Composites ◽

Interlaminar Shear ◽

Modified Epoxy

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.

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