scholarly journals Effect of Water Absorption on Flexural Properties of Kenaf/Glass Fibres Reinforced Unsaturated Polyester Hybrid Composites Rod

2022 ◽  
Vol 30 (1) ◽  
pp. 397-412
Author(s):  
Bassam Hamid Alaseel ◽  
Mohamed Ansari Mohamed Nainar ◽  
Noor Afeefah Nordin ◽  
Zainudin Yahya ◽  
Mohd Nazim Abdul Rahim

This study investigates the effect of water absorption on the flexural strength of kenaf/ glass/unsaturated polyester (UPE) hybrid composite solid round rods used for insulating material applications. Three volume fractions of kenaf/glass fibre 20:80 (KGPE20), 30:70 (KGPE30), and 40:60 (KGPE40) with three different fibre arrangement profiles of kenaf fibres were fabricated by using the pultrusion technique and were aimed at studying the effect of kenaf fibres arrangement profile and its content in hybrid composites. The fibre/ resin volume fraction was maintained constant at 60:40. The dispersion morphologies of tested specimens were observed using the scanning electron microscope (SEM). The findings were compared with pure glass fibre-reinforced UPE (control) composite. The water absorption results showed a clear indication of how it influenced the flexural strength of the hybrid and non-hybrid composites. The least affected sample was observed in the 30KGPE composite type, wherein the kenaf fibre was concentrated at the centre of a cross-section of the composite rod. The water absorption reduced the flexural strength by 7%, 40%, 24%, and 38% of glass/UPE (control), 20KGPE, 30KGPE, and 40KGPE composites, respectively. In randomly distributed composite types, the water absorption is directly proportional to the volume fraction of kenaf fibre. At the same time, flexural properties were inversely proportional to the volume fraction of kenaf fibres. Although the influence of water absorption on flexural strength is low, the flexural strength of pultruded hybrid composites was more influenced by the arrangement of kenaf fibre in each composite type than its fibre loading.

Kenaf fibres have acquired enormous attention in recent years, owing to their economic viability and environmental acceptability. Kenaf (natural) fibres have been started to replace the glass fibre (synthetic) in mechanical, electrical applications and have been utilized in several applications of industrial engineering. The current study deals with water absorption of kenaf/glass fibre reinforced unsaturated polyester composite materials used in high voltage polymeric insulator rods. The kenaf/glass hybrid composites were based on 20%, 30% and 40%(by volume) of kenaf fibers replacement glass fibres with modified 60 vol.% unsaturated polyester resins. The composites were immersedin distilled water at room temperature, and composites resistance to water absorption in terms of the rate of water absorption was determined.A considerable difference in the properties of water absorption of the hybrid composite was found demonstrating that the water absorption effect on the characteristics of insulator rods depends on the arrangement and volume fraction of kenaf fibre of the composite used. Based on the results obtained, a slight effect of water absorption on pure glass fibre composite (control) was observed. The addition of kenaf fibre on glass fibre composite rod increased the water absorption of the composite. It was shown that glass fibres surrounding kena ffibre reduced water absorption. Despite the fact that 40 vol.% of kenaf fibre composite had the highest natural fibre content, it showed the lowest water absorption because of its arrangement on all composite diameters, and also because of being surrounded by glass fibres. All of the materials reached equilibrium and ceased to absorb water after 300 hours


2017 ◽  
Vol 888 ◽  
pp. 228-233 ◽  
Author(s):  
Nurshairatun Amira Rozali ◽  
Mohamad Bashree Abu Bakar ◽  
Mohamad Najmi Masri ◽  
Muhammad Azwadi Sulaiman ◽  
Mazlan Mohamed ◽  
...  

Hybrid kenaf/glass fibre mat reinforced unsaturated polyester (UPE) composites have been prepared by using simple hand lay up moulding technique. The composites with various formulations were characterized by flexural test while water absorption behaviour were investigated with immersion in distilled water at room temperature. The result shows that the hybrid composites with kenaf fibre mat at the innermost layers (glass fibre mat at the outer layers) has given the highest flexural strength and modulus. On the other hand, water absorption study shows that, the hybrid composites with glass fibre mat at the innermost layers (kenaf fibre mat at the outer layers) showed the highest water uptake and thickness swelling. Further investigations on morphological properties were also done to correlate the mechanical properties of the hybrid kenaf/glass fibre mat reinforced UPE composites.


2011 ◽  
Vol 46 (1) ◽  
pp. 51-61 ◽  
Author(s):  
Mohd Hafiz Zamri ◽  
Hazizan Md Akil ◽  
Azhar Abu Bakar ◽  
Zainal Arifin Mohd Ishak ◽  
Leong Wei Cheng

Author(s):  
EKHLAS A. OSMAN ◽  
ANATOLI VAKHGUELT ◽  
IGOR SBARSKI ◽  
SAAD A. MUTASHER

Effects of water absorption on the flexural properties of kenaf-unsaturated polyester composites and kenaf/recycled jute-unsaturated polyester composites were investigated. In the hybrid composites, the total fiber content was fixed to 20 wt%. In this 20 wt%, the addition of jute fiber varied from 0 to 75%, with increment of 25%. The result demonstrates the water absorption and the thickness swelling increased with increase in immersion time. Effects of water absorption on flexural properties of kenaf fiber composites can be reduced significantly with incorporation of recycled jute in composites formulation. The process of absorption of water was found to approach Fickian diffusion behavior for both kenaf composites and hybrid composites.


Author(s):  
MK Gupta ◽  
Vipul Deep

In this work, the effect of water absorption and stacking sequences on the mechanical properties (i.e. impact, tensile and flexural) of hybrid sisal/glass polyester composites has been studied. Each composite laminate is prepared by the hand lay-up technique followed by static compression using about 20 wt% of fibre content. Different stacking sequences are obtained by changing the position and number of glass layers keeping a total of eight plies in each composite. Water absorption behaviour is investigated by soaking the composite specimens in the distilled water until saturation and its characteristics such as sorption, diffusion and permeability coefficient are measured. The obtained results suggested that the mechanical and water resistance properties of sisal composites are considerably enhanced by the incorporation of glass fibre. There is 23%, 29% and 46% improvement in tensile strength, flexural strength and impact strength respectively in hybrid composites than that of sisal composite. However, the effect of water absorption showed a significant reduction in the mechanical performance of all the composites. Morphological analysis by scanning electron microscope has been also performed to support the statement as weakening of fibre–matrix interfacial bonding by water absorption.


2020 ◽  
Vol 867 ◽  
pp. 68-74
Author(s):  
Sugiman Sugiman ◽  
Atin Martino ◽  
Paryanto Dwi Setyawan ◽  
Buan Anshari

The paper presents the effect of CaCO3 content on the tensile, flexural and water absorption properties of bamboo fiber/polystyrene-modified unsaturated polyester composites. Two volume fractions of bamboo fibers had been used with the CaCO3 content varied from 2.5 to 10 (wt%). The tensile and flexural properties were used to characterize the composites. In addition, the water absorption and its effect of the flexural properties had also been conducted. The results showed that at the bamboo content of 30%, adding CaCO3 up to 10wt% tended to decrease the tensile strength and elastic modulus of bamboo fiber/modified unsaturated polyester composites up to 27% and 4%, respectively; however, at the bamboo content of 20%, its effect was not significant for both the tensile strength and the elastic modulus. Adding CaCO3 seemed not to have a significant effect for both the flexural strength and modulus. Having exposed in distilled water, CaCO3 did not significantly affect the water uptakes and the flexural properties of bamboo fiber/modified unsaturated polyester composites; however, the flexural strength and modulus significantly decreased in the ranges of 24 - 45% and 36 - 43%, respectively, compared to those in dry condition.


2019 ◽  
Vol 61 (4) ◽  
pp. 369-375
Author(s):  
Sivalingam Prabhakaran ◽  
Vijayan Krishnaraj ◽  
Mouleeswaran Senthilkumar ◽  
Redouane Zitoune ◽  
Krishna Shankar

2021 ◽  
pp. 002199832110047
Author(s):  
Mahmoud Mohamed ◽  
Siddhartha Brahma ◽  
Haibin Ning ◽  
Selvum Pillay

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.


2011 ◽  
Vol 8 (2) ◽  
pp. 551-560
Author(s):  
Baghdad Science Journal

In this study, composite materials were prepared using unsaturated polyester resin as binder with two types of fillers (sawdust and chopped reeds). The molding method is used to prepare sheets of UPE / sawdust composite and UPE / chopped reeds composite. The mechanical properties were studied including flexural strength and Young's modulus for the samples at normal conditions (N.C). The Commercial wood, UPE and its composite samples were immersed in water for about 30 days to find the weight gain (Mt%) of water for the samples, also to find the effect of water on their flexural strength and Young's modulus. The results showed that the samples of UPE / chopped reeds composite gained highest values of flexural strength (24.5 MPa) and Young's modulus (5.1 GPa) as compared with other composites at (N.C). The results showed that the wet samples of sawdust composite have lowest values of weight gain (Mt %) of water (0.043%) as compared with other composites after immersion. Also it’s showed a slight decrease in values of Young's modulus for all the samples after immersion as compared with the samples at (N.C). Finally it’s showed a slight decrease in values of flexural strength for all the samples except for the composite material formed from UPE / chopped reeds which showed an increase in the value of flexural strength after immersion, where the wet samples of UPE / chopped reeds composite gained (29 MPa) as compared with the samples at (N.C).


Sign in / Sign up

Export Citation Format

Share Document