Sandwich-structured bamboo powder/glass fibre-reinforced epoxy hybrid composites – mechanical performance in static and dynamic evaluations

A layer of woven E-glass fibre was embedded each at top and bottom layer of bamboo-filled epoxy, producing sandwich-structured hybrid composites. The incorporation of woven glass fibre was intended to slow down the crack propagation in composites. Different bamboo powder loading was applied to analyse its effect on the static and dynamic mechanical properties of composites. The composite with the lowest bamboo powder loading of 10% marked the highest tensile strength, where the strength decreased as the loading increased. Poor bamboo-epoxy adhesion, observed from the SEM, leads to more chances of pull out fibres when tensile load was applied. Opposite trend was observed in flexural strength, where the highest loading of 30% marked the highest value of flexural strength. The dynamic evaluation was carried out with respect to temperature, which ranged from 25°C to 150°C, and at a fixed frequency of 1 Hz. Effective stress transfer between the fibre and the matrix takes place in composites with 30% bamboo powder loading, shown by the lowest peak height of the Tanδ curves. The significant increase in the storage modulus values for the composites at low temperature compared to the rubbery plateau region at high temperature suggested the high utility of the composites at low temperature regardless of the effect of the percentage increment in bamboo powder loading. These results showed that the bamboo powder inclusion helps in bestowing stiffness to the composites with 30% as the optimum percentage in this dynamic mechanical evaluation. It can be suggested that the introduction of woven-typed fibre into short fibre composites in sandwich structure, as discussed in this study, can slow down the failure of composites, and thus notify users before the total failure

Dynamic behaviour of woven bio fiber composite

The effect of weaving pattern and natural filler addition on the dynamic properties of composite structure was investigated. The reinforcement effect of plain, basket, and twill weave were compared with randomly oriented natural fiber in short form. An experimental modal analysis was used to determine the fundamental natural frequency and modal damping factor of composite structure. The results for a woven reinforced composite were compared with those of a randomly oriented short fiber composite. Reinforcement with woven form enhanced the fundamental natural frequency, while randomly oriented short fiber enhanced the damping factor of composite material. In addition, mechanical properties, such as tensile and flexural behavior, were examined to understand the effect of reinforcement on the composite material. The sisal bio fiber with woven form enhanced the properties of the composite material

The effects of different length of pineapple leaf fibre (PALF) on tensile properties of random oriented composites

Pineapple, AnanasComosus is one of the most primary tropical plant in Malaysia and abundantly available waste materials produced every yea. Previously, there were many pineapples waste available. To date, the use of fibres that were extracted from the pineapple leaf is still limited due to lack of information, knowledge and facilities available to process the leaf into potential materials in various applications. This present study covered on the tensile properties of PALFs composites reinforced with vinyl ester resin in different length of fibre. The composites were fabricated by using hand lay-up technique with different fibre length of PALF. There were three different type of composites which are short (15 mm), mixed (15-30 mm) and long (30 mm) PALF. Based on the result, the highest tensile strength was achieved by the composites that was prepared using the long PALF which is 25.77 MPa while mixed PALF composites showed the highest in tensile modulus (2.848 GPa). In summary, the usage of PALFs in the fabrication of composites had great potential to reduce the non-renewable materials for real-life application

Tensile properties of hybrid biocomposite reinforced epoxy modified with carbon nanotube (CNT)

A tensile test was conducted to investigate the mechanical properties of hybrid bio-composites that have potential for application in helmet shells. Helmets can protect users from serious injuries, reducing traumas and deaths. Military helmets are made with 19 layers of Kevlar, and bicycle helmets are made of glass fibre reinforced plastic materials that are costly. Replacing or reducing these synthetic fibres with plant fibres would reduce costs and may allow for such materials to be recyclable, biodegradable, and more abundant, as the material has been ground or crunched. Flax woven fibre was used to fabricate one panel of composite (Flax only) and three panels of hybrid composite (FLXC, FLXG, and FLXK). In this project, the epoxy resin was modified by weight with 0 wt.%, 0.5 wt.%, 1 wt.%, 1.5%, and 2 wt.% multi-walled carbon nanotubes (MWCNTs). This study examined the effect of multi-walled carbon nanotube (MWCNT) concentration on the tensile properties of hybrid biocomposites. The experimental results suggested that the MWCNTs played an important role in improving the mechanical performance of hybrid biocomposites. It was found that optimum carbon nanotube (CNT) concentration improved the tensile performance of the materials by 2% to 5%. However, an excess CNT concentration led to the deformation of materials and reduced their mechanical performance

Effects of fibre treatment on mechanical properties of kenaf fibre reinforced composites: a review

There have been review on kenaf fibre (KF) production and mechanical properties but lacks review on the treatment and surface modification on kenaf fibre. Therefore, this study is to show the type of treatment that have been done by previous researcher. A lot of methods have been investigated to find the optimum method to obtain better condition and properties for kenaf fibre. The present review describes those applied to kenaf fibre. The most widely used chemical treatment is the alkaline treatment using a sodium hydroxide (NaOH) solution, followed by a silane treatment. Variety of chemical concentration for NaOH solution and silane solution are investigated and a few combined treatments such as alkaline-silane, alkaline-steam, alkaline-radiation and alkaline-bleaching are also discussed. Thus, this paper presents an overview of investigated treatment methods with application to kenaf fibre and what are the effects of chemical treatment to the surface of kenaf fibre and the mechanical properties of the composites developed based on treated kenaf fibre

Low velocity impact behaviour and post-impact characteristics of kenaf/glass hybrid composites with various weight ratios

The aim of this work was to analyze the effects of hybridizing kenaf and glass fibre to develop hybrid composites with varying weight ratios on the low velocity impact response and the post-impact properties of the obtained composites. Four main process had been carried out in this study, which were the fabrication of composites, the low velocity impact testing, the dye penetrant evaluation on the impacted composites and the compression testing on the impacted samples after the dye penetrant evaluation. This research was motivated by the increasing demand for lightweight, cost-effective and environmentally friendly materials to be applied at an industrial level. In this paper, natural kenaf fibre was hybridized with synthetic glass fibre in an attempt to create an attractive material for the composite industries. The materials were fabricated in seven samples with varying weight percentage ratios of the fibres, while the glass fibre was used as the outermost layer for each formulation. A sample made entirely from kenaf fibre and another one entirely from glass fibre were also included for comparison. The formulation that demonstrated the best tensile performance – that with the weight percentage ratio of 25% kenaf fibre and 75% glass fibre – was then subjected to low velocity impact tests. Four impact energy levels of 10 J, 20 J, 30 J and 40 J were applied to study the propagation of impact in the composite with the optimum formulation. The closed curve on the graph plotting force versus displacement indicated the success of the specimen in absorbing the dissipated energy up to 40 J. The dye penetrant test was performed to investigate the damage area progression, and it revealed that a higher energy level will produce greater damage. Compression after impact tests indicated that the compression damage decreased as the impact energy was increased. Considering that the hybrid composite with the weight ratio of 25% kenaf fibre and 75% glass fibre approached the performance of the material made entirely from glass fibre, it may be concluded that it can be employed for product development in environmentally friendly technologies

Low velocity impact and compression after impact properties of hybrid bio-composites modified with multi-walled carbon nanotubes

Aerospace structures are prone to impact which affected their residual strength. The aim of this paper to investigate the impact and after-impact behaviour of multi-walled carbon nanotube (MWCNTs) as nanofiller enhanced flax/carbon fibre composites (FLXC) and flax/glass fibre composites (FLXG) hybrid composites. Wet lay-up method was used to fabricate the hybrid composites. The hybrid composites were impacted with impact energies ranging from 5J to 20J, with different types of surface susceptible to the impactor to compare their response under loading. Compression after impact (CAI) testing were done to evaluate the after-impact properties of the hybrid composites. Obtained results found that FLXG composites impacted at glass surface (G-FLX) showed better impact properties compared to C-FLX composites. In another end, it was found that the compressive strength of FLXG composites is higher compared to FLXC composites due to severe damage occurred on FLXC composites surface compared to FLXG composites. Therefore, from the results, it can be concluded that FLXG hybrid composites shows good behaviour to be applied as the interior and functional surfaces inside an aircraft

Water absorption associated with gamma irradiation on kevlar/oil palm EFB hybrid composites

The objective of this work is to analyse the water absorption behaviour on the gamma irradiated Kevlar/Oil Palm EFB hybrid composites. The hybrid composites were fabricated through manual hand lay-up method. Different layering sequence of hybrid composites were fabricated which is Oil Palm EFB/Kevlar/ Oil Palm EFB (OP/K/OP) and Kevlar/Oil Palm EFB/Kevlar (K/OP/K). Various Gamma radiationdoses;25 kGy, 50kGy and 150 kGy were exposed to the composites. The results showed that for both layering pattern, the water absorption for non-irradiated hybrid composites absorbed more water than irradiated hybrid composites. Water uptake for non-irradiated K/OP/K is 51% and with radiation is 21% at 50 kGy. Hybrid OP/K/OP that is not irradiated absorbed less water which is 27% as compared to the same hybrid but with radiation only 17%of water being absorbed at 50 kGy. The results showed that irradiated hybrid composites absorb less water compared to non-irradiated hybrid composites. This suggest that crosslinking took place due to the radiation. This implies that with radiation of certain dose could improves the properties of water absorption forKevlar/ Oil Palm EFB hybrid composites

Effect of silver nanopowder on mechanical, thermal and antimicrobial properties of kenaf/HDPE composites

This study aims to investigate the effect of AgNPs on the mechanical, thermal and antimicrobial activity of kenaf/HDPE composites. AgNP material was prepared at different contents, from 0, 2, 4, 6, 8 to 10 wt%, by an internal mixer and hot compression at a temperature of 150 °C. Mechanical (tensile, modulus and elongation at break), thermal (TGA and DSC) and antimicrobial tests were performed to analyze behavior and inhibitory effects. The obtained results indicate that the effect of AgNP content displays improved tensile and modulus properties, as well as thermal and antimicrobial properties. The highest tensile stress is 5.07 MPa and was obtained at 10wt, TGA showed 10 wt% and had improved thermal stability and DSC showed improved stability with increased AgNP content. The findings of this study show the potential of incorporating AgNP concentrations as a secondary substitute to improve the performance in terms of mechanical, thermal and antimicrobial properties without treatment. The addition of AgNP content in polymer composite can be used as a secondary filler to improve the properties

A review on the orthotics and prosthetics and the potential of kenaf composites as alternative materials for ankle-foot orthosis

Since ancient Egypt, orthosis was generally made from wood and then later replaced with metal and leather which are either heavy, bulky, or thick decreasing comfort among the wearers. After the age of revolution, the manufacturing of products using plastics and carbon composites started to spread due to its low cost and form-fitting feature whereas carbon composite were due to its high strength/stiffness to weight ratio. Both plastic and carbon composite has been widely applied into medical devices such as the orthosis and prosthesis. However, carbon composite is also quite expensive, making it the less likely material to be used as an Ankle-Foot Orthosis (AFO) material whereas plastics has low strength. Kenaf composite has a high potential in replacing all the current materials due to its flexibility in controlling the strength to weight ratio properties, cost-effectiveness, abundance of raw materials, and biocompatibility. The aim of this review paper is to discuss on the possibility of using kenaf composite as an alternative material to fabricate orthotics and prosthetics. The discussion will be on the development of orthosis since ancient Egypt until current era, the existing AFO materials, the problems caused by these materials, and the possibility of using a Kenaf fiber composite as a replacement of the current materials. The results show that Kenaf composite has the potential to be used for fabricating an AFO due to its tensile strength which is almost similar to polypropylene's (PP) tensile strength, and the cheap raw material compared to other type of materials