Long term hydrothermal effect on the mechanical and thermo-mechanical properties of carbon nanofiber doped epoxy composites

2018 ◽  
Vol 38 (3) ◽  
pp. 251-261 ◽  
Author(s):  
Sunirmal Saha ◽  
Smrutisikha Bal
Keyword(s):  
Water Absorption ◽  
Epoxy Polymer ◽  
Carbon Nanofiber ◽  
Flexural Modulus ◽  
Epoxy Composites ◽  
After Effects ◽  
Micro Cracks ◽  
Influence Of Water ◽  
Carbon Nanofibre ◽  
Experimental Findings

AbstractThe influence of water absorption on the mechanical and thermo-mechanical behaviour of carbon nanofibre (CNF) doped epoxy composites was investigated. When immersed in seawater for a long interval of 6 months, all the composite specimens endured saturation whilst weight change of composites was periodically monitored after removal of travelling specimens from a water-beaker. The equilibrium water content and the diffusion coefficient of all composites were evaluated with the help of Fick’s law of diffusion. The results demonstrated a general reduction in flexural modulus and strength, hardness, storage modulus and glass transition temperature (Tg) for seawater exposed specimens due to absorption of seawater as compared to their unexposed specimens. After-effects of water absorption such as plasticisation, swelling of epoxy polymer, interfacial damages and micro-cracks, were marked as the main reasons behind the deterioration of properties. However, among all, the least degradation in properties was observed in the nanocomposite with 0.75 wt.% CNFs loading. Such trivial degradation in properties is due to formation of strong interface of CNFs with the epoxy polymer. The experimental findings were further confirmed by the microstructures of fractured specimens using field emission scanning electron microscopy.

scholarly journals Flexural Properties of Halloysite Nanotubes (HNTS) and Carbon Nanotubes (CNTS) Toughened Epoxy Composites

2020 ◽  
Vol 9 (4) ◽  
pp. 1670-1675
Keyword(s):  
Carbon Nanotubes ◽  
Surface Roughness ◽  
Flexural Modulus ◽  
Halloysite Nanotubes ◽  
Epoxy Composites ◽  
Flexural Properties ◽  
Sem Images ◽  
Micro Cracks ◽  
Dispersion State ◽  
Solution Casting Method

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.

Influence of Water Absorption on The Selected Properties of Hemp Hurds Composites

2015 ◽  
Vol 10 (1) ◽  
pp. 123-132
Author(s):  
Lucia Kidalova ◽  
Nadezda Stevulova ◽  
Eva Terpakova
Keyword(s):  
Water Absorption ◽  
Influence Of Water

scholarly journals Enhanced flexural properties of aramid fiber/epoxy composites by graphene oxide

2019 ◽  
Vol 8 (1) ◽  
pp. 484-492 ◽  
Author(s):  
Yinqiu Wu ◽  
Bolin Tang ◽  
Kun Liu ◽  
Xiaoling Zeng ◽  
Jingjing Lu ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Flexural Strength ◽  
Interfacial Shear Strength ◽  
Flexural Modulus ◽  
Weight Fraction ◽  
Interfacial Shear ◽  
Aramid Fiber ◽  
Epoxy Composites ◽  
Flexural Properties ◽  
Pure Epoxy

Abstract The reinforcing effect of graphene oxide (GO) in enhancing the flexural strength and flexural modulus of aramid fiber (AF)/epoxy composites were investigated with GO-AFs at a weight fraction of 0.1-0.7%. The flexural strength and flexural modulus of the composite reached 87.16 MPa and 1054.7 MPa, respectively, which were about 21.19% and 40.86% higher than those of the pure epoxy resin, respectively. In addition, the flexural properties and interfacial shear strength (IFSS) of composite reinforced by GO-AFs were much higher than the composites reinforced by AFs due to GO improved the interfacial bonding between the reinforcement material and matrix.

scholarly journals Mechanical and Morphological Properties of Bio-Phenolic/Epoxy Polymer Blends

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 773
Author(s):  
Ahmad Safwan Ismail ◽  
Mohammad Jawaid ◽  
Norul Hisham Hamid ◽  
Ridwan Yahaya ◽  
Azman Hassan
Keyword(s):  
Mechanical Properties ◽  
Phase Separation ◽  
Polymer Blends ◽  
Epoxy Polymer ◽  
Flexural Modulus ◽  
Polymeric Materials ◽  
Morphological Properties ◽  
Comparison Results ◽  
Unique Material ◽  
Different Types

Polymer blends is a well-established and suitable method to produced new polymeric materials as compared to synthesis of a new polymer. The combination of two different types of polymers will produce a new and unique material, which has the attribute of both polymers. The aim of this work is to analyze mechanical and morphological properties of bio-phenolic/epoxy polymer blends to find the best formulation for future study. Bio-phenolic/epoxy polymer blends were fabricated using the hand lay-up method at different loading of bio-phenolic (5 wt%, 10 wt%, 15 wt%, 20 wt%, and 25 wt%) in the epoxy matrix whereas neat bio-phenolic and epoxy samples were also fabricated for comparison. Results indicated that mechanical properties were improved for bio-phenolic/epoxy polymer blends compared to neat epoxy and phenolic. In addition, there is no sign of phase separation in polymer blends. The highest tensile, flexural, and impact strength was shown by P-20(biophenolic-20 wt% and Epoxy-80 wt%) whereas P-25 (biophenolic-25 wt% and Epoxy-75 wt%) has the highest tensile and flexural modulus. Based on the finding, it is concluded that P-20 shows better overall mechanical properties among the polymer blends. Based on this finding, the bio-phenolic/epoxy blend with 20 wt% will be used for further study on flax-reinforced bio-phenolic/epoxy polymer blends.

An Experimental Study of Dropped Ply Region in Composite

2006 ◽  
Vol 326-328 ◽  
pp. 1769-1772
Author(s):  
Chun Wang Zhao ◽  
Yong Ming Xing
Keyword(s):  
Experimental Study ◽  
Stress Concentration ◽  
Failure Mechanisms ◽  
Experimental Results ◽  
Epoxy Composites ◽  
Moire Interferometry ◽  
Concentration Region ◽  
Micro Cracks ◽  
Stress Concentration Region ◽  
Mechanical Study

A micro mechanical study of Carbon/Epoxy composites with internally dropped plies has been made using micro-moiré interferometry. The experimental results show that there is a stress concentration region before the dropped ply. Micro cracks were initiated and propagated in this region. Two failure mechanisms in the dropped ply region were observed.

The direct architecture of carbon fiber-carbon nanofiber hierarchical reinforcements for superior interfacial properties of CF/epoxy composites

2018 ◽  
Vol 30 (3) ◽  
pp. 620-630 ◽  
Author(s):  
Hao Zheng ◽  
Quanjiang Li ◽  
Chaoyong Yu ◽  
Xue Zhu ◽  
Pinting Guo ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Carbon Nanofiber ◽  
Interfacial Properties ◽  
Epoxy Composites

scholarly journals Effect of Gravel-sand Ratio on Physico-mechanical, Thermal and Macrostructural Properties of Micro Epoxy Polymer Concrete based on a Mixture of Alluvial-dune Sand

2020 ◽  
Vol 14 (1) ◽  
pp. 247-261
Author(s):  
Zineb Kerrida ◽  
Hichem Berkak ◽  
Zoubir Makhloufi ◽  
Madani Bederina ◽  
Ahmida Ferhat
Keyword(s):  
Thermal Conductivity ◽  
Water Absorption ◽  
Epoxy Resin ◽  
Epoxy Polymer ◽  
Polymer Concrete ◽  
Dune Sand ◽  
Optimal Values ◽  
Compressive And Flexural Strengths ◽  
Mechanical Performances ◽  
Crushed Limestone

Introduction: In the Polymer Concrete (PC) composites, aggregates are the most important constituent, which considerably affect their performance. The purpose of this experimental study is to examine the effect of Gravel-to-Sand (G/S) ratio on the physico-mechanical, thermal and microstructural properties of epoxy micro-polymer concrete made up of local aggregates. Materials & Methods: The Micro Epoxy Polymer Concrete (MEPC) studied consists of epoxy resin as a binder and a mixture of two types of sands (alluvial (0/0.63 mm) and dune (0/4 mm) sands), as well as crushed limestone gravel (3/8 mm). Six compositions were prepared with two epoxy resin contents (10% and 14% of the total weight of mixture) and three G/S ratios (0.25, 0.50 and 0.75). The studied properties are density, water absorption, compressive and flexural strengths, thermal conductivity, thermal diffusivity, specific heat and macrostructure. Results & Discussion: The obtained results show that the G/S ratio, as well as the epoxy resin content, has a significant influence on the properties of MEPC. In addition, 14% epoxy resin and the G/S ratio of 0.75 can be considered as optimal values, which lead to very interesting physico-mechanical performances (denser and less porous material, more resistant with almost similar thermal conductivity). Moreover, the density, the water absorption and the optical microscopic observation confirm that mixes containing 14% epoxy are more impermeable, compact and homogeneous than those containing 10% epoxy. Conclusion: Finally, it should be noted that the incorporation of aggregates being relatively coarse decreases the grains’ specific surface and reduces the porosity of the granular mix, which enable the epoxy product to completely cover the surface of mineral grains. A perfect covering of aggregate grains with a bender improves the adhesion between the aggregates and the polymer matrix.

scholarly journals Ketahanan Papan Partikel Terhadap Suhu Tinggi, Serapan Air dan Perilaku Patah

2019 ◽  
Vol 2 (3) ◽  
pp. 230
Author(s):  
Dian Sestining Ayu ◽  
Edi Kurniadi
Keyword(s):  
Physical Properties ◽  
Water Absorption ◽  
Particle Density ◽  
Flexural Modulus ◽  
Wood Powder ◽  
Wood Floor ◽  
Structural Purpose ◽  
Density Values ◽  
Shell Particles ◽  
Coconut Shells

Wood is widely used for structural and non-structural purposes. In non-structural purpose, wood is used, among others, as furniture, parquet (wood floor), partitions and so on. In line with the decreasing availability of wood, the price of wood is becoming increasingly expensive. In certain uses, substitute materials such as particle boards have been started to use. Particle boards are generally composed of certain wood powder wastes. This study aimed to look for alternative materials for building particle boards from coconut shells. The particle boards to be tested were composed of coconut shells with the addition of certain wood powder which is added with certain percentage. Particle boards were printed with a certain size, given certain pressure and tested for their physical properties. The physical properties of the particle boards tested included particle density, water absorption, dry flexural modulus, and dry bending fracture modulus. The results showed that the best mixture composition capable of producing density values, water absorption, fracture modulus and optimum modulus of elasticity were found in the proportion of mixtures of 70-90% coconut shell particles and 30-10% wood particles.

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