Effect of Silane Treatments on Mechanical Performance of Kenaf Fibre Reinforced Polymer Composites: A Review

Author(s):  
Mohd Nurazzi Norizan ◽  
Aisyah Humaira Alias ◽  
F.A. Sabaruddin ◽  
M.R.M. Asyraf ◽  
S.S. Shazleen ◽  
...  

Abstract Natural cellulosic fibres, such as kenaf, can be used in polymeric composites in place of synthetic fibres. The rapid depletion of synthetic resources such as petroleum and growing awareness of global environmental problems associated with synthetic products contribute to the acceptance of natural fibres as reinforcing material in polymer composite structures. In Africa and Asia, kenaf is considered a major crop used for various cordage products such as rope, twine, and burlap and in construction, it is used for thermal insulation of walls, floors, and roofs and soundproofing solutions. In the furniture and automotive industry, it is used to manufacture medium-density fibreboard (MDF) and other composite materials for structural applications. Kenaf is primarily composed of cellulose (approximately 40 to 80%), which accounts for its superior mechanical performance. Kenaf fibres are chemically treated before mixing with the polymer matrix to improve their fibre interaction and composite performance. The alkaline treatment with sodium hydroxide (NaOH) solution is the most frequently used chemical treatment, followed by a silane treatment. Numerous chemical concentrations of NaOH and silane solutions are investigated and several combined treatments such as alkaline-silane. The present review discusses the effect of silane treatments on the surface of kenaf fibre on the fabrication of polymer composites and their mechanical properties.

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Francis Dantas ◽  
Kevin Couling ◽  
Gregory J. Gibbons

Abstract The aim of this study was to identify the effect of material type (matrix and reinforcement) and process parameters, on the mechanical properties of 3D Printed long-fibre reinforced polymer composites manufactured using a commercial 3D Printer (Mark Two). The effect of matrix material (Onyx or polyamide), reinforcement type (Carbon, Kevlar®, and HSHT glass), volume of reinforcement, and reinforcement lay-up orientation on both Ultimate Tensile Strength (UTS) and Flexural Modulus were investigated. For Onyx, carbon fibre reinforcement offered the largest increase in both UTS and Flexural Modulus over unreinforced material (1228 ± 19% and 1114 ± 6% respectively). Kevlar® and HSHT also provided improvements but these were less significant. Similarly, for Nylon, the UTS and Flexural Modulus were increased by 1431 ± 56% and 1924 ± 5% by the addition of carbon fibre reinforcement. Statistical analysis indicated that changing the number of layers of reinforcement had the largest impact on both UTS and Flexural Strength, and all parameters were statistically significant.


Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2188
Author(s):  
Andrew N. Dickson ◽  
Hisham M. Abourayana ◽  
Denis P. Dowling

Three-dimensional (3D) printing has been successfully applied for the fabrication of polymer components ranging from prototypes to final products. An issue, however, is that the resulting 3D printed parts exhibit inferior mechanical performance to parts fabricated using conventional polymer processing technologies, such as compression moulding. The addition of fibres and other materials into the polymer matrix to form a composite can yield a significant enhancement in the structural strength of printed polymer parts. This review focuses on the enhanced mechanical performance obtained through the printing of fibre-reinforced polymer composites, using the fused filament fabrication (FFF) 3D printing technique. The uses of both short and continuous fibre-reinforced polymer composites are reviewed. Finally, examples of some applications of FFF printed polymer composites using robotic processes are highlighted.


2009 ◽  
Vol 417-418 ◽  
pp. 13-16
Author(s):  
Zahid R. Khokhar ◽  
Ian A. Ashcroft ◽  
Vadim V. Silberschmidt

Fibre reinforced polymer composites (FRPCs) are being increasingly used in structural applications where high specific strength and stiffness are required. The performance of FRPCs is affected by multi-mechanism damage evolution under loading which in turn is affected by microstructural stochasticity in the material. This means that the fracture of a FRPC is a stochastic process. However, to date most analyses of these materials have treated them in a deterministic way. In this paper the effect of stochasticity in FRPCs is investigated through the application of cohesive zone elements in which random properties are introduced. These may be termed ‘stochastic cohesive zone elements’ and are used in this paper to investigate the effect of microstructural randomness on the fracture behaviour of cross-ply laminate specimens loaded in tension. It is seen from this investigation that microstructure can significantly affect the macroscopic response of FRPC’s, emphasizing the need to account for microstructural randomness in order to make accurate prediction of the performance of laminated composite structures.


Author(s):  
Igor Souza Hoffman ◽  
Jorge Henrique Piva ◽  
Augusto Wanderlind ◽  
Elaine Guglielmi Pavei Antunes

abstract: The use of GFRP (Glass Fiber Reinforced Polymers) structural profiles in the construction sector is growing due to their attractive properties, such as high mechanical strength and durability in aggressive environments. With this, it is necessary to conduct studies that deepen the knowledge about the performance of these materials in structural applications. Therefore, this work aims to analyze the mechanical performance of reinforced concrete beams coated with GFRP profiles, in comparison to reinforced concrete beams, by analyzing groups with different spacing between transversal reinforcement. In all groups there was no change in the longitudinal reinforcement, and the D and Q groups were, respectively, made up of transverse reinforcement spaced twice and quadruple the one calculated for the reference beams, and presented the GFRP profiles in their constitution. All beams were tested at four-point bending, and strain gauges were installed in one of the beams of each group studied. The results obtained in the tests showed an increase in strength of 83.67% in the beams of group D, and 79.91% for group Q, in relation to the references. The analysis of longitudinal deformations made it possible to verify increases in stiffness and the moment of cracking in composite beams. Thus, based on this study, the composite structures studied may constitute future solutions for constructions exposed to aggressive environmental conditions, in order to increase their durability and also to contribute to the design of such structural elements with lower reinforcement rates.


Author(s):  
A. K. Gupta ◽  
S. P. Harsha

The two phase polymer composites have been extensively used in various structural applications; however, there is need to further enhance the strength and stiffness of these polymer composites. Carbon nanotubes (CNTs) can be effectively used as secondary reinforcement material in polymer based composites due to their superlative mechanical properties. In this paper, effects of multiwall nanotubes (MWNTs) reinforcement on epoxy–carbon polymer composites are investigated using experiments. MWNTs synthesized by chemical vapor deposition (CVD) technique and amino-functionalization are achieved through acid-thionyl chloride route. Diglycidyl ether of bisphenol-A (DGEBA) epoxy resin with diethyl toluene diamine (DETDA) hardener has been used as matrix. T-300 carbon fabric is used as the primary reinforcement. Three types of test specimen of epoxy–carbon composite are prepared with MWNT reinforcement as 0%, 1%, and 2% MWNT (by weight). The resultant three phase nanocomposites are subjected to tensile test. It has been found that both tensile strength and strain at failure are substantially enhanced with the small addition of MWNT. The analytical results obtained from rule of mixture theory (ROM) shows good agreement with the experimental results. The proposed three phase polymer nanocomposites can find applications in composite structures, ballistic missiles, unmanned arial vehicles, helicopters, and aircrafts.


2020 ◽  
pp. 152808372097442
Author(s):  
Parul Sahu ◽  
MK Gupta

Recently, researchers and scientists are trying to overcome the environmental burden by using biocomposites in engineering applications as far as possible. The main source of biocomposites is cellulosic fibres which is a class of natural fibres. Instead of many advantages of cellulosic fibres, they and their polymer composites suffer from some limitations as well. The environmental conditions are one of the most important issues to degradation behavior of the cellulosic fibres polymer composites (CFPCs). Among the environmental conditions, water absorption is an important ground to degradation in the mechanical performance of the CFPCs, which resists them to be used in outdoor applications. Several studies have been presented on water absorption characteristics of cellulosic fibres and its polymer-based biocomposites. Further, the consequence of water uptake on the mechanical performance of biocomposites was also reported in many studies. In most of the cases, a negative effect of water absorption was observed, whereas in a few cases a positive effect was also seen. In the present study, mechanics and kinetics of water absorption for CFPCs are discussed. Further, a detailed literature review on water absorption of cellulosic fibres and their different types of polymer-based biocomposites has also been carried out. Furthermore, studies reported on the effect of water absorption on the mechanical properties were also systematically presented. Moreover, all the possible remedies to lower the water absorption capacity were also discussed in the present review paper.


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