A Comparative Study of Double Layers Al2O3/Al2O3 and Al2O3/SiO2 Prepared by Microwave and Natural Drying

In this work, a comparative study of green multilayered ceramic bodies prepared by natural and microwave drying techniques was investigated. The multilayered ceramic with combination of Al2O3 /Al2O3 and Al2O3/SiO2 samples were prepared via compression method. Alumina powder, Al2O3 with the particle sizes of 90μ, <45μm and silica powder, SiO2 with particle sizes of  <45μm were used in this study. Measured linear shrinkage of multilayered ceramic bodies show that microwave drying contribute to lower shrinkage value compared to the natural drying method. The characterization of the microstructure of multilayered ceramic body also shown that microwave technique can create a good bonding structure especially at the critical interface layer. In fact, the implementation of microwave drying also significantly reduced the drying time and produced a good and homogenous final structur

Effect of Multi-walled Carbon Nanotube on Mechanical Properties of Kenaf/Polypropylene Composites / Zakaria Razak...[et al.]

Kenaf fibre has a high potential to be used for composite reinforcement in hybrid composites. It has been varying combinations of physical and mechanical properties, such as low cost, low density, high strength and stiffness. Carbon nanotubes (CNTs) are encouraging additives for polymer composites due to their excellent special mechanical, electrical, and thermal properties. The compounded samples were organized into test specimens by injection moulding machine. The composites contained 1, 2, 3 and 4 wt% multi-walled carbon nanotubes (MWCNT). The purpose of this study is to investigate the mechanical properties of kenaf core fibre with a weight fraction of 30 wt% and varying weight fraction of MWCNT. The injection moulding technique is used to prepare the composite specimens for tensile, flexural and impact tests in accordance to the ASTM D638, ASTM D790 and ASTM D256 respectively. The optimum properties have been observed at MWCNT 3 wt% with the impact strength of, 8.512Kj/m2, tensile strength, 23.447 MPa, Young’s modulus, 1865.950 MPa, flexural strength, 36.728MPa and a flexural modulus, 1826.121 MPa

Effects of Fiber Content and Processing Parameters on Tensile Properties of Unidirectional Long Kenaf Fiber Reinforced Polylactic-Acid Composite / Izdihar Tharazi...[et al.]

Recent developments within the field of natural fiber-reinforced polymer composite have led to a renewed interest in fully biodegradable composite or green composite. Interest in using green composites is due to environmental awareness concerns as well as stringent government regulations. The study is aimed to determine the optimum percentage of fiber content for unidirectional long kenaf fiber (LKF) reinforced polylactic-acid composites. In addition, the influence of processing parameters has also been investigated but only for the optimum fiber content. The percentage of kenaf used are 10 wt% to 50 wt% prepared by film stacking method with a hot-press machine. A series of tensile tests was performed to obtain the tensile strength, including the Young’s modulus of the composite. The 40 wt% fiber composites showed tensile strength, and the Young’s modulus increased linearly to 230% and 650%, respectively. Furthermore, for 50 wt% of fiber content, tensile strength and young modulus increased linearly to 244% and 625% compare to pure polymer, respectively. It was found that better tensile properties were achieved with 50%wt fiber composites produced at a temperature of 200oC, 5MPa compression pressure and 5 minutes holding time. Applications for fabricated compoistes are in non-structural to structural with medium loads, especially in the field of aerospace, automotive, and building construction industries

Mechanical Properties of Compression Molded Epoxy Polymer Composites Reinforced with Kenaf Fibers / Nur Farhani Ismail ...[et al.]

Kenaf composites have been widely used in the engineering and industrial applications such as air cleaner, dashboard, insulation mats, and fibreboard. Due to considerable attentions; kenaf fibres are reinforced in polymers for the fabrication of polymer composites. This work deals with the fabrication and characterizations of untreated and treated temafa kenaf fibres. The microstructure (SEM), flexural properties and tensile properties of the prepared kenaf polymer composites were discussed throughout this study. The kenaf fibres were treated with 6 wt% sodium hydroxide, NaOH solution for 24 hours soaking time. The epoxy thermoset reinforced with randomly oriented temafa kenaf was fabricated using compression molding technique. The composite samples of kenaf were prepared with different kenaf fibre loadings; 20 wt%, 30 wt%, 40 wt%, 50 wt% and 60 wt% . It was found that the properties of kenaf composites mainly depend on the compositions of kenaf fibres. It has also been investigated that the treatment influences the properties of kenaf itself. Overall, the results revealed that the treated kenaf composites have better mechanical properties such as flexural strength as compared to the untreated kenaf composites. However, it is observed that the flexural strength also increased with increasing percentage loading of kenaf fibres. These prepared kenaf composites will perform better mechanical properties than existing polymer may be used in automotive applications

Kenaf fiber composites: a review on synthetic and biodegradable polymer matrix

This review paper deals with the previous and current works published on the kenaf fiber composites. Kenaf is grown commercially in South East Asia country and widely used in the construction and infrastructure as well as in the automotive industry. Kenaf fiber is usually reinforced with synthetic based polymer resin such as polypropylene. However, recent studies tend to concern towards the environmental issues which kenaf fiber act as an alternative natural fiber competitor. Moreover, the combination of the natural fiber and the biodegradable polymer able to reduce the negative impact on human health. Hence, researcher-initiated the interest focusing on the biodegradable materials obtained from the renewable sources. A huge attention gave to the kenaf fiber reinforced bio-polymer materials such as polylactic acid. The processing technique and the fiber orientation within the composite materials are discussed extensively in order to obtain the maximum composite performance. Results indicated that the mechanical properties; tensile strength and tensile modulus, are improved as the kenaf fiber was aligned in uni-direction. Therefore, this paper overview on the kenaf retting types in the common form of kenaf fibers and discussing the thermoplastic polymer matrices types used in the fabrication processes. In addition, the challenging of using kenaf fibers composites and its application in the automotive industry also highlighted

The effects of maleic anhydride grafted PP (MAPP) on the mechanical properties of injection moulded kenaf/CNTs/PP composites

Composite materials have increasingly become crucial in manufacturing engineering products and producing commodity materials in the major industries including; automotive, aerospace, marine, construction, agriculture and health science. However, several improvements regarding the strength, dimensional stability and the cost of production are required. In this study, composite of Kenaf, multi-wall carbon nanotube (MWCNT) and polypropylene (PP) with maleic anhydride-grafted polypropylene (MAPP) are examined. The results highlight that increasing MAPP loading, in turn, increases the value of the mechanical properties. The composites are produced by blending kenaf/MWCNT/PP using a Sigma blade mixer and injection moulding. Injection moulding is a significant operation used to produce plastic products. In the study, Kenaf core fibre was mixed with MWCNT and polypropylene, in addition to MAPP. The MAPP is added by applying different percentage (1, 2, 3 and 4 wt. %) during the blending process. The main objective of the study was to analyse the effects of MAPP concentrations on the mechanical properties of the Kenaf/MWCNT/PP composite. The results of the study established that MAPP 3 wt. % concentration with MWCNT 3 wt. % loading and Kenaf 30 wt. % filler provide optimum results for the composites. There was approximately, a 21% enhance in tensile strength of Kenaf 30 wt. %/MWCNT, 3 wt. %/MAPP, 3 wt. %/PP observed compared to the (without) MAPP composite. The composites with coupling agent stimulate better filler dispersion between Kenaf, MWCNT and PP observed using a scanning electron microscope (SEM) and field-emission scanning electron microscope (FESEM)

Management of COVID-19 vaccines cold chain logistics:a scoping review

BACKGROUND: Successful mass vaccination programmes are public health achievements of the contemporary world. While pharmaceutical companies are actively developing new vaccines, and demonstrating results of effectiveness and safety profiles, concerns on COVID-19 vaccine management are under-reported. We aimed to synthesise the evidence for efficient cold chain management of COVID vaccines. METHODS: The scoping review’s conduct and reporting were based on the PRISMA–ScR 2018 checklist. We searched from April 2020 to January 2022 for publications in PubMed (LitCovid), Scopus and ScienceDirect. All review stages were pilot-tested to calibrate 2 reviewers. Articles on cold chain logistics and management were included, while publications solely describing COVID vaccines, their development and clinical aspects of the vaccine, were excluded. To capture relevant data, charting was conducted by one reviewer and verified by another. Results were analysed thematically and summarised descriptively in a table and in-text. RESULTS AND DISCUSSION: We assessed 6984 potentially relevant citations. We included 14 publications originating from USA (n = 6), India (n = 2), Finland, Spain, Bangladesh, Netherlands, Switzerland and Ethiopia. They were reported as reviews (4), policy or guidance documents (3), experimental studies (2), case reports (2), expert commentary (1), phenomenological study (1), and decision-making trial and evaluation laboratory trial (1). The findings were presented in three themes: (i) regulatory requirements for cold-chain logistics, (ii) packaging and storage, and (iii) transportation and distribution. A conceptual framework emerged linking regulatory requirements, optimal logistics operation and formulation stability as the key to efficient cold chain management. Recommendations were made for improving formulation stability, end-product storage conditions, and incorporating monitoring technologies. CONCLUSION: COVID-19 vaccines require special end-to-end supply cold chain requirements, from manufacture, and transportation to warehouses and healthcare facilities. To sustain production, minimise wastage, and for vaccines to reach target populations, an efficient and resilient vaccine supply chain which is assisted by temperature monitoring technologies is imperative. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s40545-022-00411-5