Mechanical performances of hygrothermally conditioned CNT/epoxy composites using seawater

2017 ◽  
Vol 37 (6) ◽  
pp. 633-645 ◽  
Author(s):  
Smrutisikha Bal ◽  
Sunirmal Saha
Keyword(s):  
Water Absorption ◽  
Moisture Absorption ◽  
Epoxy Composites ◽  
Flexural Properties ◽  
Absorption Study ◽  
Pure Epoxy ◽  
Pull Out ◽  
Maximum Duration ◽  
Mechanical Performances ◽  
Better Than

Abstract Hygrothermic aging of epoxy and carbon nanotube (CNT)/epoxy composites (0.5, 0.75, and 1 wt.%) was studied for their application suitability in seawater environments. The specimens were emerged in seawater and kept at constant temperature of 30°C for a maximum duration of 180 days. The specimens were periodically weighed for water absorption study and tested for mechanical as well as thermal properties. All aged samples were showing some amount of degradation owing to their moisture-absorption rates. CNT composites absorbed less moisture than pure epoxy because of the presence of nanofillers. C0.75 was found to be hygrothermally more stable reflecting minimum reduction in flexural properties and glass transition temperature value, which was due to least moisture/water absorption. Deterioration of properties was significant in C1, though it was better than pure epoxy. Fractographic analysis by scanning electron microscopy (SEM) revealed interfacial debonding as the dominant failure mechanism, resulting in pull out of nanotubes.

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.

Influence of fiber surface treatments on physico-mechanical behaviour of jute/epoxy composites impregnated with aluminium oxide filler

2017 ◽  
Vol 51 (28) ◽  
pp. 3909-3922 ◽  
Author(s):  
Priyadarshi Tapas Ranjan Swain ◽  
Sandhyarani Biswas
Keyword(s):  
Water Absorption ◽  
Benzoyl Chloride ◽  
Moisture Absorption ◽  
Natural Fiber ◽  
Hybrid Composites ◽  
Aluminium Oxide ◽  
Fiber Surface ◽  
Epoxy Composites ◽  
Fiber Reinforced ◽  
Chemically Treated

The present paper discovers the effect of ceramic filler inclusion on physico-mechanical and water absorption behaviour of untreated and chemically treated (alkali and benzoyl chloride treated) bi-directional jute natural-fiber-reinforced epoxy composites. In practice, the major drawbacks of using natural fibers are their high degree of moisture absorption and poor dimensional stability. Currently, chemical treatments are able to induce fiber modifications that increase their resistance when utilized in composite products. Jute fibers were subjected to various chemical modifications to improve the interfacial bonding with the matrix. In this study, an analysis has been carried out to make pre-treated jute fiber (10, 20, 30 and 40 wt.%) and different filler content (5 and 10 wt.%) with epoxy-based composites. A comparative study of all the untreated jute/aluminium oxide based hybrid composites with chemically treated jute/aluminium oxide based hybrid composites was carried out. The investigational result reveals that chemically treated composites considerably improved the mechanical properties of the composite. The maximum water absorption resistance and strength properties were found with benzoyl chloride-treated fiber-reinforced composite. Lastly, the surface morphology of fractured surfaces after tensile and flexural testing is studied using scanning electron microscope.

Hybridization effect on water absorption and flexural properties of E-glass/banana fibre/epoxy composites

2021 ◽  
Author(s):  
Raghavendra Pai ◽  
L. Bangarappa ◽  
K.S. Lokesh ◽  
D. Shrinivasa Mayya ◽  
C.R. Naveen ◽  
...  
Keyword(s):  
Water Absorption ◽  
Epoxy Composites ◽  
Flexural Properties ◽  
Hybridization Effect ◽  
Banana Fibre

scholarly journals Moisture Absorption Studies of COIR and Sisal Short Fiber Reinforced Polymer Composites

2021 ◽  
Vol 9 (9) ◽  
pp. 116-127
Author(s):  
Ambareesh K V
Keyword(s):  
Water Absorption ◽  
Polymer Composites ◽  
Moisture Absorption ◽  
Natural Fiber ◽  
Sea Water ◽  
Natural Fibre ◽  
Epoxy Composites ◽  
Fiber Reinforced ◽  
Short Fibers ◽  
Reinforced Polymer

Abstract: Easy availability of natural fibre, low cost and ease of manufacturing have urged the attention of researchers towards the possibility of reinforcement of natural fiber to improve their mechanical properties and study the extent to which they satisfy the required specifications of good reinforced polymer composite for industrial and structural applications. Polymer composites made of natural fiber is susceptible for moisture. Moisture absorption in such composites mainly because of hydrophilic nature of natural fibers. Water uptake of natural fiber reinforced composites has an effect on different. Lot of researchers prepared the natural fiber reinforced composites without conducting water absorption tests; hence it is the potential area to investigate the behavior of the composites with different moisture absorption. In this research the experimental sequence and the materials are used for the study of coir and Sisal short fiber reinforced epoxy matrix composites. The coir and Sisal short fibers are made into the short fibers with 10 mm x 10 mm x 5 mm size. The Epoxy Resin-LY556(Di glycidyl ether of bi phenol) and Hardner-HYD951 (Tetra mine), the water absorption behaviors are analyzed in the coir and Sisal short fibers reinforced epoxy composites. The water absorption behaviors of the epoxy composites reinforced with the coir and sisal short fibers with 25, 30 and 35wt% were analyzed at three different water environments, such as sea water, distilled water, and tap water for 12 days at room temperature. It was observed that the composites show the high level of the water absorption percentage at sea water immersion as compared to the other water environments. Due to the water absorption, the mechanical properties of macro particle/epoxy composites were decreased at all weight percentages. Keywords: Natural fibre, Moisture absorption, Coir and sisal short fibre, Reinforced polymer composites, Water absorption behaviour Polymer matrix composite (Epoxy resin) using Coir and sisal short fibre and to study its moisture absorption behaviour

scholarly journals The Effect of Hybridisation on Mechanical Properties and Water Absorption Behaviour of Woven Jute/Ramie Reinforced Epoxy Composites

Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2964
Author(s):  
Cionita Tezara ◽  
Agung Efriyo Hadi ◽  
Januar Parlaungan Siregar ◽  
Zalinawati Muhamad ◽  
Mohammad Hazim Mohamad Hamdan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Water Absorption ◽  
Moisture Absorption ◽  
Hybrid Composites ◽  
Critical Issue ◽  
Natural Fibre ◽  
Industrial Applications ◽  
Epoxy Composites ◽  
Aqueous Environment ◽  
Stacking Sequence

Recently, the most critical issue related to the use of natural fibre-reinforced polymer composites (NFRPC) is the degradation properties of composites exposed to the environment. NFRPC’s moisture absorption behaviour has adverse effects on the composite’s mechanical properties and dimensional stability. The purpose of this study is to analyse the mechanical properties of epoxy composites reinforced by jute–ramie hybridisation. This study also analysed the effect of stacking sequence hybridisation of the jute–ramie composite on water absorption behaviour. A five-layer different type of stacking sequence of single and hybrid jute–ramie is produced with the hand lay-up method. The results obtained from this study found that the mechanical properties and water absorption behaviour of a single jute fibre are lower compared to a single ramie fibre. The hybrid of jute–ramie has been able to increase the performance of composite compared to pure jute composites. The mechanical properties of the hybrid jute–ramie composite show a reduction effect after exposure to an aqueous environment due to the breakdown of fibre matrix interfacial bonding. However, after 28 days of immersion, all types of the stacking sequence’s mechanical properties are still higher than that of pure epoxy resin. In conclusion, the appropriate sequence of stacking and selecting the material used are two factors that predominantly affect the mechanical properties and water absorption behaviour. The hybrid composites with the desired and preferable properties can be manufactured using a hand-lay-up technique and used in the various industrial applications.

scholarly journals Effect of Moisture Absorption on the Flexural Properties of Basalt/CNT/Epoxy Composites

2012 ◽  
Vol 13 (3) ◽  
pp. 187-189 ◽  
Author(s):  
Man-Tae Kim ◽  
Kyong-Yop Rhee ◽  
Hyeon-Ju Kim ◽  
Dong-Ho Jung
Keyword(s):  
Moisture Absorption ◽  
Epoxy Composites ◽  
Flexural Properties ◽  
Effect Of Moisture

Monitoring of mechanical properties of prestressed glass fiber epoxy composites over 12 months after fabrication

2021 ◽  
pp. 002199832110047
Author(s):  
Mahmoud Mohamed ◽  
Siddhartha Brahma ◽  
Haibin Ning ◽  
Selvum Pillay
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Flexural Strength ◽  
Compressive Residual Stress ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Epoxy Composites ◽  
Flexural Properties ◽  
Initial Increase ◽  
Fiber Volume

Fiber prestressing during matrix curing can significantly improve the mechanical properties of fiber-reinforced polymer composites. One primary reason behind this improvement is the generated compressive residual stress within the cured matrix, which impedes cracks initiation and propagation. However, the prestressing force might diminish progressively with time due to the creep of the compressed matrix and the relaxation of the tensioned fiber. As a result, the initial compressive residual stress and the acquired improvement in mechanical properties are prone to decline over time. Therefore, it is necessary to evaluate the mechanical properties of the prestressed composites as time proceeds. This study monitors the change in the tensile and flexural properties of unidirectional prestressed glass fiber reinforced epoxy composites over a period of 12 months after manufacturing. The composites were prepared using three different fiber volume fractions 25%, 30%, and 40%. The results of mechanical testing showed that the prestressed composites acquired an initial increase up to 29% in the tensile properties and up to 32% in the flexural properties compared to the non-prestressed counterparts. Throughout the 12 months of study, the initial increase in both tensile and flexural strength showed a progressive reduction. The loss ratio of the initial increase was observed to be inversely proportional to the fiber volume fraction. For the prestressed composites fabricated with 25%, 30%, and 40% fiber volume fraction, the initial increase in tensile and flexural strength dropped by 29%, 25%, and 17%, respectively and by 34%, 26%, and 21%, respectively at the end of the study. Approximately 50% of the total loss took place over the first month after the manufacture, while after the sixth month, the reduction in mechanical properties became insignificant. Tensile modulus started to show a very slight reduction after the fourth/sixth month, while the flexural modulus reduction was observed from the beginning. Although the prestressed composites displayed time-dependent losses, their long-term mechanical properties still outperformed the non-prestressed counterparts.

Enhancing the mechanical and water resistance performances of bamboo particle reinforced polypropylene composite through cell separation

Holzforschung ◽  
2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Dan Ren ◽  
Xuexia Zhang ◽  
Zixuan Yu ◽  
Hankun Wang ◽  
Yan Yu
Keyword(s):  
Water Absorption ◽  
Cell Separation ◽  
Water Resistance ◽  
Dynamic Mechanical Properties ◽  
Simple Method ◽  
Interface Modification ◽  
Wood Particles ◽  
Bamboo Fibers ◽  
Pp Composites ◽  
Mechanical Performances

AbstractIt is frequently observed that bamboo particle composites (BPCs) do not show higher mechanical performances than the corresponding wood particles composites (WPCs), although bulk bamboo is much stronger than wood in mechanical performances. Herein this phenomenon was demonstrated from the cell compositions in the applied bamboo particles. To address that, a simple method to physically separate bamboo fibers (BFs) and bamboo parenchyma cells (BPs) from a bamboo particle mixture was developed. Polypropylene (PP) composites with pure BFs, BPs, a mixture of BFs and BPs (BFs + BPs), wood particles (WPs) as fillers were prepared. The flexural and dynamic mechanical properties, water absorption, and thermal properties were determined. The BF/PP composites showed the best mechanical performances (MOR at 35 MPa, MOE at 2.4 GPa), followed by WP/PP, (BF + BP)/PP, and BP/PP. They also exhibited the lowest water absorption and thickness swelling. Little difference was found for the thermal decomposition properties. However, a lower activation energy of BF/PP compared with BP/PP implied an uneven dispersion of BFs and weaker interfacial interaction between BF and PP. The results suggest that the mechanical performances and water resistance of bamboo particle/polymer composites can be significantly improved through cell separation. However, interface modification should be applied if higher performances of BF/PP composites are required.

scholarly journals The Effect of Polymer Waste Addition on the Compressive Strength and Water Absorption of Geopolymer Ceramics

2021 ◽  
Vol 11 (8) ◽  
pp. 3540
Author(s):  
Numfor Linda Bih ◽  
Assia Aboubakar Mahamat ◽  
Jechonias Bidossèssi Hounkpè ◽  
Peter Azikiwe Onwualu ◽  
Emmanuel E. Boakye
Keyword(s):  
Public Health ◽  
Compressive Strength ◽  
Fracture Surface ◽  
Water Absorption ◽  
Chemical Bonding ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Polymer Waste ◽  
Pull Out

The quantity of polymer waste in our communities is increasing significantly. It is therefore necessary to consider reuse or recycling waste to avoid an increase in the risk to public health. This project is aimed at using pulverized low-density polyethylene (LDPE) waste as a source to reinforce and improve compressive strength, and to reduce the water absorption of geopolymer ceramics (GC). Clay:LDPE composition consisting of 5%, 10%, and 15% LDPE was geopolymerized with an NaOH/Na2SiO3 solution and cured at 30 °C and 50 °C. Characterization of the geopolymer samples was carried out using XRF and XRD. The microstructure was analyzed by SEM and chemical bonding by FTIR. The SEM micrographs showed LDPE particle pull-out on the geopolymer ceramics’ fracture surface. The result showed that the compressive strength increases with the addition of pulverized polymer waste compared to the controlled without LDPE addition. Water absorption decreased with an increase in LDPE addition in the geopolymer ceramics composite.

Evidence for direct water absorption by the shoot of the desiccation-tolerant plant Vellozia flavicans in the savannas of central Brazil

2005 ◽  
Vol 21 (5) ◽  
pp. 585-588 ◽  
Author(s):  
Rafael S. Oliveira ◽  
Todd E. Dawson ◽  
Stephen S. O. Burgess
Keyword(s):  
Water Absorption ◽  
Moisture Absorption ◽  
Terrestrial Plants ◽  
Desert Ecosystems ◽  
Common View ◽  
Central Brazil ◽  
Tolerant Plants ◽  
Aerial Roots ◽  
Alternative Water ◽  
Specialized Structure

Our common view on water uptake by terrestrial plants is that it occurs via absorption by roots from the soil substrate. However, it has long been known that plants exhibit alternative water-absorption strategies, particularly in drought-prone environments. Examples include many tropical epiphytic orchids which use a specialized structure called velamen radicum around their aerial roots for moisture absorption directly from the air (Capesius & Barthlott 1975), specialized trichomes in bromeliads (Andrade 2003, Benzing 1990), uptake by hydathodes into leaves of species inhabiting dry desert ecosystems of Namibia (Martin & von Willert 2000) and foliar absorption by coastal California redwoods during the summer fog season (Burgess & Dawson 2004). One of the most intriguing and yet, least-studied examples of adaptations to severe water limitation is found with desiccation-tolerant plants (also called resurrection plants). During drought periods, the water content of these plants can equilibrate with the low relative humidity of the air to the point that the plants appear dead. However, when water is supplied, these plants fully rehydrate (Alpert 2000, Bewley & Krochko 1982) and become physiologically active. Desiccation-tolerant vascular plants are rare in most ecosystems but diverse in tropical inselbergs (granitic outcrops; Porembski & Barthlott 2000). Relatively little is known about inselberg species particularly from an ecophysiological perspective (see Lüttge 1997 and Klüge & Brulfert 2000 for reviews).

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