The Combined Effect of Mercerisation, Silane Treatment and Acid Hydrolysis on the Mechanical Properties of Sisal Fibre/Epoxy Resin Composites

MRS Advances ◽  
2020 ◽  
Vol 5 (23-24) ◽  
pp. 1225-1233
Author(s):  
Wilson Webo ◽  
Maina Maringa ◽  
Leonard Masu

ABSTRACTThe effect of the combined chemical treatment of sisal fibres through the subsequent processes of mercerisation (alkali-treatment), then silane treatment and eventually acid hydrolysis, on sisal fibre were investigated. The effect of the treated fibres on the tensile strength and stiffness, flexural strength and stiffness, compression strength and shear strength of their composites with epoxy resin were also studied. Scanning electron microscopy studies of the surfaces of the treated and untreated fibres showed that the chemical treatment processes enhanced the removal of surface extractives and therefore increased the roughness of the surfaces of the fibres in the range of 20 % - 70 %. This avails an increased reinforcement surface area for interlocking with matrix and is, therefore, expected to enhance adhesion of the two. The treated fibre reinforced composites were observed to have higher values of tensile strength and stiffness, flexural strength and stiffness, compression strength and shear strength than the un-treated fibre reinforced composites. These higher values were attributed to better interfacial bonding due to better mechanical interlocking between the treated fibres and epoxy resin arising from the increased roughness of the treated fibres.

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Wilson Webo ◽  
Leonard Masu ◽  
Maina Maringa

The effect of the combined chemical treatment of sisal fibres through the subsequent processes of mercerisation (alkali treatment), then silane treatment and eventually acid hydrolysis, on sisal fibre was investigated. The effect of the treated fibres on the impact toughness and hardness of their composites with epoxy resin was also studied. Scanning electron microscopy of the surfaces of the treated and untreated fibres showed that the chemical treatment processes enhanced the removal of surface impurities and therefore increased the roughness of the surfaces of the fibres. This avails an increased surface area for interlocking with matrix and is, therefore, expected to enhance adhesion of the two. The treated fibre reinforced composites were observed to have higher values of impact toughness and hardness than the untreated fibre reinforced composites. These higher values were attributed to better interfacial bonding due to better mechanical interlocking between the treated fibres and epoxy resin arising from the increased roughness of the treated fibres.


Fibre reinforced composites have been an essential concern in various fields, especially in the field of aerospace owing to its high strength to weight ratio, toughness, corrosion resistant and low cost. Natural fibre reinforced composites have produced better results in mechanical properties like impact, toughness and fatigue strengths when compared to synthetic fibre reinforced composites. Recently researches have been conducted on different varieties of natural fibres for use in plastics such as jute straw, wood, rice husk, wheat, barley etc. Natural fibres have also attracted the attention of researchers due to its availability, renewability, degradability and most importantly ecofriendly. In this work an attempt is made to improve the mechanical properties of the composite and also to enhance the compatibility of the fibres with the matrix. The composite is prepared by reinforcing banana fibres into unsaturated epoxy matrix using hand layup method. Mechanical properties such as tensile strength, flexural strength and hardness strengths are carried out on the specimens made by reinforcing with 5%, 10 % and 15 %concentration of banana fibre by weight. The results showed that the composite with 15% concentration of banana fibre produced higher tensile strength of 21.43 MPa, flexural strength of 0.895 kPa and Shroud hardness of 59.3.


2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Xiaoguang Zheng ◽  
Qi Ren ◽  
Huan Xiong ◽  
Xiaoming Song

As one of the major contributors to the early failures of steel bridge deck pavements, the bonding between steel and asphalt overlay has long been a troublesome issue. In this paper, a novel composite bonding structure was introduced consisting of epoxy resin micaceous iron oxide (EMIO) primer, solvent-free epoxy resin waterproof layer, and ethylene-vinyl acetate (EVA) hot melt pellets. A series of strength tests were performed to study its mechanical properties, including pull-off strength tests, dumbbell tensile tests, lap shear tests, direct tension tests, and 45°-inclined shear tests. The results suggested that the bonding structure exhibited fair bonding strength, tensile strength, and shear strength. Anisotropic behaviour was also observed at high temperatures. For epoxy resin waterproof layer, the loss of bonding strength, tensile strength, and shear strength at 60°C was 70%, 35%, and 39%, respectively. Subsequent pavement performance-oriented tests included five-point bending tests and accelerated wheel tracking tests. The impacts of bonding on fatigue resistance and rutting propagation were studied. It was found that the proposed bonding structure could provide a durable and well-bonded interface and was thus beneficial to prolong the fatigue lives of asphalt overlay. The choice of bonding materials was found irrelevant to the ultimate rutting depth of pavements. But the bonding combination of epoxy resin waterproof and EVA pellets could delay the early-stage rutting propagation.


2021 ◽  
Vol 2021 ◽  
pp. 102-108
Author(s):  
J. Domenech-Pastor ◽  
P. Diaz-Garcia ◽  
D. Garcia

Composites are materials formed by the combination of two or more components that acquire better properties than the ones obtained by each component on its own. Composites have been widely used in the industry due to its light weight and good mechanical properties. To improve these properties several layers of reinforced material (e.g., carbon fibre) are overlapped which produce an increase in the fibre consumption. In this sense Tailored Fibre Placement (TFP) embroidery can offer good opportunity to reduce the consumption of reinforced fibre while improving the mechanical properties due to the alignment of the fibres in the effort direction. This study analyzes the performance of carbon fibre reinforced composites with Polyester resin made with TFP embroidery technology against flexural strength efforts and without using plain woven fabrics to demonstrate that the use of reinforcement fabrics in composites can be optimized by a curved alignment of the fibers. Two different structures were embroidered with TFP technology, one simulating a woven fabric with straight unidirectional alignment of fibres in horizontal and vertical direction, and a second structure made with curvilinear alignment of carbon fibers. After the study of the flexural mechanical properties an improvement of 18% was obtained in maximum flexural strength.


2011 ◽  
Vol 31 (6-7) ◽  
Author(s):  
Xiuju Zhang ◽  
Juncai Shen ◽  
Tingting Yang ◽  
Bihua Ye ◽  
Zhidan Lin ◽  
...  

Abstract In this study, waste cotton cloth (RC) was bonded with soluble starches as an adhesive, then dried, cut into particles and filled into polylactic acid (PLA) to achieve resource efficiency. The mechanical, thermal and crystallization properties of the composites were characterized. The results indicated that with the addition of RC, the tensile strength, impact strength and flexural strength of PLA composites improved. Also, the heat distortion temperatures increased slowly, indicating that RC filled into PLA can be turned back into useful items without the degradation of PLA composites. This is a good way to give direction to the resource utilization of waste clothing. The addition of RC could significantly reduce the spherulitic size of PLA.


2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Hanna M. Brodowsky ◽  
Anne Hennig

Abstract Natural fibre–reinforced composites are more sustainable than other composites with respect to the raw materials. Their properties are attractive due to high specific properties, and especially so wherever high damping is valued. As the interphase between fibre and matrix is the region of highest stresses, a strong bond between fibre and matrix is essential for any composites’ properties. The present study compares two methods of determining the interfacial shear stress in natural fibre–reinforced composites: the single fibre fragmentation test and the single fibre pullout test. The studied composites are flax fibre reinforced epoxy. For a variety of fibre–matrix interaction, the fibres are treated with a laccase enzyme and dopamine, which is known to improve the fibre–matrix shear strength. In the observed samples, single fibre fragmentation test data, i.e. of fracture mode and fragment length, scatter when compared to pullout data. In single fibre pullout tests, the local interfacial shear strength showed a 30% increase in the laccase-treated samples, compared to the control samples. The method also permitted an evaluation of the frictional stress occurring after surface failure.


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