scholarly journals EFFECT OF WATER ABSORPTION ON THE MECHANICAL PROPERTIES \OF FLAX FIBER REINFORCED EPOXY COMPOSITES

Author(s):  
Umit Huner
2016 ◽  
Vol 47 (2) ◽  
pp. 211-232 ◽  
Author(s):  
G Rajeshkumar ◽  
V Hariharan ◽  
TP Sathishkumar ◽  
V Fiore ◽  
T Scalici

Phoenix sp. fiber-reinforced epoxy composites have been manufactured using compression molding technique. The effect of reinforcement volume content (0%, 10%, 20%, 30%, 40%, and 50%) and size (300 µm particles, 10 mm, 20 mm, and 30 mm fibers) on quasi-static and dynamic mechanical properties was investigated. Moreover, the water absorption properties of composites were analyzed at different environmental conditions (10℃, 30℃, and 60℃). For each reinforcement size, composites loaded with 40% in volume show highest tensile and flexural properties. Furthermore, composites with 300 µm particles present the best impact properties and the lowest water absorption, regardless of the environmental condition. The dynamic mechanical properties of the composites loaded with 40% in volume were analyzed by varying the reinforcement size and the load frequency (i.e., 0.5 Hz, 1 Hz, 2 Hz, 5 Hz, and 10 Hz). It was found that the glass transition temperature of short fiber-reinforced composites is higher than that of the composite loaded with particles.


2020 ◽  
Vol 54 (20) ◽  
pp. 2781-2801 ◽  
Author(s):  
Yousef Saadati ◽  
Gilbert Lebrun ◽  
Jean-Francois Chatelain ◽  
Yves Beauchamp

Using natural fibers as reinforcement in polymer matrix composites necessitates evaluating the latter under different modes of solicitation. This allows extracting its material properties for engineering design and research purposes. The main objective of the study is preparing a consistent set of material properties for unidirectional flax fiber-reinforced epoxy composite with defined composition and basic configuration. These data are prerequisites for growing researches on flax fiber-reinforced epoxy composites, especially for numerical analysis purposes using the finite element method. In this work, partially green unidirectional-flax fiber-reinforced epoxy composites are tested for physical and mechanical properties and studied for their failure modes. Tension, compression, flexion, and shear properties, as well as physical properties like density, specific heat capacity and thermal diffusivity, are evaluated according to ASTM standard test methods. Flax fibers, which are composites by themselves, come in bundles in the composites and demonstrate a complex behavior. Therefore, a fractographic analysis has been conducted to understand the macro and microscale failure mechanisms to correlate them with the material properties. The results are in good agreement with those of the literature, when available, but they mainly show the specific behavior of unidirectional-flax composites subject to different solicitation modes, especially compression and direct shear modes evaluated this way for the first time for unidirectional-flax fiber-reinforced epoxy composite. They cover most of the data required for engineering design and numerical analysis by methods like finite element method, particularly for simulating the machining process of flax fiber-reinforced epoxy composite in the ongoing works.


2020 ◽  
Vol 4 (1) ◽  
pp. 3-11 ◽  
Author(s):  
Raghu M J ◽  
Govardhan Goud

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.


2015 ◽  
Vol 35 (6) ◽  
pp. 545-550 ◽  
Author(s):  
Varun Mittal ◽  
Shishir Sinha

Abstract The present article presents a study on the mechanical and water absorption properties of bagasse fiber-reinforced epoxy composites. Bagasse fibers are subjected to chemical treatment with 1% sodium hydroxide followed by 1% acrylic acid at ambient temperature to enhance the bonding strength between the fiber-polymer, resulting in high values of the mechanical properties and a reduction in the water absorption properties of the composites. We analyzed the optimum value of fiber treatment, and it was found that 15% treated fiber loading yields enhanced the mechanical properties together with a reduction in water absorption properties.


Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1261
Author(s):  
Catarina S. P. Borges ◽  
Alireza Akhavan-Safar ◽  
Eduardo A. S. Marques ◽  
Ricardo J. C. Carbas ◽  
Christoph Ueffing ◽  
...  

Short fiber reinforced polymers are widely used in the construction of electronic housings, where they are often exposed to harsh environmental conditions. The main purpose of this work is the in-depth study and characterization of the water uptake behavior of PBT-GF30 (polybutylene terephthalate with 30% of short glass fiber)as well as its consequent effect on the mechanical properties of the material. Further analysis was conducted to determine at which temperature range PBT-GF30 starts experiencing chemical changes. The influence of testing procedures and conditions on the evaluation of these effects was analyzed, also drawing comparisons with previous studies. The water absorption behavior was studied through gravimetric tests at 35, 70, and 130 °C. Fiber-free PBT was also studied at 35 °C for comparison purposes. The effect of water and temperature on the mechanical properties was analyzed through bulk tensile tests. The material was tested for the three temperatures in the as-supplied state (without drying or aging). Afterwards, PBT-GF30 was tested at room temperature following water immersion at the three temperatures. Chemical changes in the material were also analyzed through Fourier-transform infrared spectroscopy (FTIR). It was concluded that the water diffusion behavior is Fickian and that PBT absorbs more water than PBT-GF30 but at a slightly higher rate. However, temperature was found to have a more significant influence on the rate of water diffusion of PBT-GF30 than fiber content did. Temperature has a significant influence on the mechanical properties of the material. Humidity contributes to a slight drop in stiffness and strength, not showing a clear dependence on water uptake. This decrease in mechanical properties occurs due to the relaxation of the polymeric chain promoted by water ingress. Between 80 and 85 °C, after water immersion, the FTIR profile of the material changes, which suggests chemical changes in the PBT. The water absorption was simulated through heat transfer analogy with good results. From the developed numerical simulation, the minimum plate size to maintain the water ingress unidirectional was 30 mm, which was validated experimentally.


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