scholarly journals Effect of Water Absorption on Mechanical Properties of Calotropis Procera Fiber Reinforced Polymer Composites

2020 ◽  
Vol 4 (1) ◽  
pp. 3-11 ◽  
Author(s):  
Raghu M J ◽  
Govardhan Goud
Keyword(s):  
Mechanical Properties ◽  
Water Absorption ◽  
Polymer Composites ◽  
Mechanical Testing ◽  
Epoxy Polymer ◽  
Calotropis Procera ◽  
Fiber Reinforced ◽  
Effect Of Water ◽  
Reinforced Polymer ◽  
Fiber Reinforced Polymer Composites

The present work investigates the effect of water absorption on mechanical properties of calotropis procera fiber reinforced epoxy polymer composites. The calotropis procera fiber chemical and mechanical testing was done to evaluate chemical composition and strength of the fiber. The composites are fabricated by reinforcing calotropis procera fiber in epoxy matrix by varying the fiber wt. % by traditional hand layup method. The water absorption of calotropis procera reinforced epoxy polymer composites at room temperature was found to increase with increasing fiber loading. The mechanical testing results of moisture exposed composites indicated decreased strength which may be due to degraded bonding between fiber and matrix.

Water Sorption of Vegetable Fiber Reinforced Polymer Composites

2016 ◽  
Vol 369 ◽  
pp. 17-23 ◽  
Author(s):  
L.H. de Carvalho ◽  
A.G. Barbosa de Lima ◽  
E.L. Canedo ◽  
A.F.C. Bezerra ◽  
W.S. Cavalcanti ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Water Absorption ◽  
Polymer Composites ◽  
Water Sorption ◽  
Glass Fibers ◽  
Fiber Reinforced Polymer ◽  
Synthetic Fibers ◽  
Reinforced Polymer ◽  
Fiber Reinforced Polymer Composites ◽  
Vegetable Fiber

Despite the ever-growing worldwide interest in the use of lignocellulosic fibers as reinforcement in either thermoset or thermoplastic matrices, the use of these fibers to replace synthetic ones, is limited. The reasons for these limitations are associated with the vegetable fiber’s heterogeneity, lower compatibility to most polymers, inferior durability, flammability, poorer mechanical properties and higher moisture absorption when compared with synthetic fibers. Nevertheless, despite these drawbacks, vegetable fiber reinforced polymer composites are lighter in weight, more sustainable and can be used for non-structural products. Strategies to minimize these drawbacks include fiber and or matrix modification, the use of compatibilizers, fiber drying and the concomitant use of vegetable and synthetic fibers, for the production of hybrid composites, the latter being an unquestionable way to increment overall mechanical and thermal properties of these hybrid systems. Here we present data on the water sorption of polymer composites having thermoset and thermoplastic matrices as a function of vegetable fiber identity, content and hybridization with glass fibers. Our data indicates that, regardless if the matrix is a thermoset of a thermoplastic, water absorption tends to be relatively independent of vegetable fiber identity and to be significantly dependent of its content. Fiber drying prior to composite manufacturing and hybridization with glass fibers leads to lower overall water absorption and higher mechanical properties.

Effect of fiber prestressing on mechanical properties of glass fiber epoxy composites manufactured by vacuum-assisted resin transfer molding

2019 ◽  
Vol 39 (1-2) ◽  
pp. 21-30
Author(s):  
Mahmoud Mohamed ◽  
Mohamed M Selim ◽  
Haibin Ning ◽  
Selvum Pillay
Keyword(s):  
Mechanical Properties ◽  
Polymer Composites ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Fiber Volume ◽  
Fiber Waviness ◽  
Reinforced Polymer ◽  
Fiber Reinforced Polymer Composites

The mechanical properties of fiber-reinforced polymer composites depend on several aspects such as the characteristics of constituents, fiber volume fraction, and manufacturing techniques. Fiber prestressing is considered a very attractive manufacturing technique that can be used to produce fiber-reinforced polymer composites with high mechanical properties. This technique has the potential to eliminate or reduce some manufacturing problems like fiber waviness. In the present study, a new approach was used to prepare prestressed fiber-reinforced polymer composites. Unidirectional E-glass fiber-stitched mats were impregnated with epoxy matrix through vacuum-assisted resin transfer molding process. Once the infusion was done, a pre-calculated tensile force was applied to the fiber mats through a hydraulic tensile machine. The impregnated fiber mats were left under tension and vacuum during curing of the epoxy matrix (24 h). Five prestressed samples were prepared by using five different prestressing levels 20, 40, 60, 80, and 100 MPa. In addition, non-prestressed (control) sample was prepared for the purpose of comparison. The influence of fiber prestressing on fiber waviness, fiber volume fraction, and void content was investigated. Flexural, tensile, and compression tests were performed to observe the effect of fiber prestressing on the mechanical properties. The results have shown the success of this new approach in producing prestressed fiber-reinforced polymer composites with high mechanical properties comparing to non-prestressed composites. The microstructure analysis has shown dramatical reduction in fiber waviness for the prestressed samples over control sample. All prestressed samples have shown higher fiber volume fraction and lower void content comparing to the control sample. Also the results have shown as the prestressing level increases, fiber volume fraction increase and void content decreases. Prestressing levels of 40 and 60 MPa were found to be the best candidates, they have led to an increase in tensile strength, compressive strength, and flexural strength by 24.2%, 72.5%, 28% and 28.6%, 100.4%, 26.1%, respectively, comparing to the non-prestressed sample. Ease of implementation and promising results of this new approach would attract the attention toward it. Automotive industry is one potential nominee to apply this approach during manufacturing of fiber-reinforced polymer leaf spring.

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